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New Spanish-language e-book about fermented foods now available for download

By Dr. Gabriel Vinderola, PhD,  Associate Professor of Microbiology at the Faculty of Chemical Engineering from the National University of Litoral and Principal Researcher from CONICET at Dairy Products Institute (CONICET-UNL), Santa Fe, Argentina

Fermented foods and beverages such as yogurt, wine, beer, kefir, kombucha, kimchi, and miso are created with the help of microbes. After more than 10,000 years of practice around the globe, fermentation has finally caught massive attention from a general public interested in knowing more about the fascinating, invisible world of microbes. In essence, the act of fermentation places food in a unique place between raw and cooked. The flavours, tastes, textures and potential health benefits of fermented foods, made possible through the presence of viable or non-viable microbes and their metabolites, are achieved through this set of ancestral food processing techniques. Today’s science allows us to see the functions of fermentation microbes that can make certain nutrients more bioavailable in foods. Fermentation can also reduce certain anti-nutrients and generate a large number of potentially beneficial microorganisms.

To help people learn about fermented foods, I was pleased to collaborate on an e-book with Ricardo Weill, an Argentinian dairy industry expert who first introduced Lactobacillus rhamnosus GG in Argentinian fermented milks in the 1990s, and Alejandro Ferrari, a biologist and scientific communications expert. The book is titled ‘Fermented Foods: microbiology, nutrition, health and culture’, and is currently available only in Spanish.

The book aimed to reach the general public, with scientific concepts but in easy-to-follow language for people with little or no previous knowledge of microbiology, nutrition or food technology. It tells the stories of many types of fermented foods around the world and adds a scientific perspective on their health benefits. The book brings together information from 38 authors from Argentina, Colombia, Japan, Spain and Finland, including ISAPP President Prof. Seppo Salminen, and Martin Russo, a professional chef in Argentina who specializes in fermentation. The book includes the following sections:

Fermentation: An anthropological view

Variety of fermented foods in Japan and other East Asian countries, and the microorganisms involved in their fermentation

Introduction to the intestinal microbiota: its role in health and the disease

Consumption of probiotic fermented milk and its impact on the immune system

Fermented milks, yogurts and probiotics

Kefir and artisanal fermented foods

Fermented meat sausages: Contribution of lactic bacteria in global quality

Lactic fermentation of cereals and Andean ancestral grains

Fermented vegetables and legumes

Fermentation of fruit drinks and drinks

Yeasts in beer and baked goods

Role of fermented foods in diet

Role of lactic acid in the beneficial effects of fermented foods

Microbiological safety of fermented foods

Fermented foods and chronic non-communicable diseases: A narrative review of the literature

Fermentation and gastronomy: A cook among scientists, a scientist among cooks

This e-book initiative started in October 2019, when a symposium about fermented food was organized by the Danone Institute of the Southern Cone (DISC).

The Danone Institute of the Southern Cone (DISC) was founded in 2008, and it is the local chapter for Argentina, Chile and Uruguay of the Danone Institute International network, which gathers 14 Danone Institutes (13 local Institutes and 1 International) in 15 countries. All Danone Institutes are non-profit organizations, dedicated to non-commercial activities and promotion of science.

Since its foundation, the DISC has collaborated with more than 200 experts taking part in different projects, and has served as a collaborative meeting place to reflect with their peers—all of them remarkable scientists coming from different and complementary specialties, focusing on key aspects of public health linked to food.

See the link to our book here:

Fermented Food: Microbiology, Nutrition, Health & Culture. (2020)

See the ISAPP press release about this book in English and en español.

Some previously-produced nutrition books that are freely available in Spanish on the DISC website are:

  • Impact of Growth and Early Development on the Population’s Health and Wellbeing. Perspectives and Reflections from the Southern Cone. (2009)
  • Healthy Growth. Between Malnutrition and Obesity in the Southern Cone. (2011)
  • The Role of Calcium and Vitamin D in Bone Health and Beyond. Perspective from the Southern Cone. (2013)
  • Methodologies Employed in Food Evaluation. An Ibero-American Vision. (2015)
  • Their Impact in Nutrition and Health. A Vision from the Southern Cone. (2018)

Bulgarian yogurt: An old tradition, alive and well

By Mariya Petrova, PhD, Microbiome insights and Probiotics Consultancy, Karlovo, Bulgaria

Family and family traditions are very important to me. Some of you may have seen my previous blog post on fermented food and my father’s tradition of making fermented cabbage and vegetables every autumn. Of course, this is not limited to my family – in Bulgaria, it is our culture and our country’s tradition. But despite the fact that I wrote about fermented vegetables first, Bulgarians are much more proud of another fermented product – yogurt.

I still remember waking up every morning when I was a kid and having a healthy homemade yogurt to start the day. I still do when I am back at home, because my father continues to make yogurt at home. Here, I’ll take you on a new adventure and tell you all about Bulgarian yogurt, an old tradition still alive in every home.

Élie Metchnikoff and his work are well familiar to anyone involved in probiotic research. In short, Metchnikoff observed in 1907 that Bulgarian peasants lived longer lives and he attributed this to their daily consumption of yogurt.

Thanks to Metchnikoff, research on Bulgaria and Bulgarian yogurt was put on the map because of our healthy way of living and eating fermented foods. You may know this part of the story. Still, few actually know that Metchnikoff was intrigued by the work of the Bulgarian researcher Stamen Grigorov a few years earlier. In fact, it was because of Stamen Grigorov’s work that we now know ‘who’ (i.e. which microbes) live in our yogurt and how essential those tiny bacteria are. In 1905 Stamen Grigorov actually discovered and isolated for the first time Lactobacillus bulgaricus (now known as Lactobacillus delbrueckii subsp. bulgaricus) from homemade yogurt. That’s why we are so proud of Bulgarian yogurt. Not only do we love to eat it, but the probiotic research was partially initiated in our country, and an entire Lactobacillus species is named after our country. There is even a small museum dedicated to Bulgarian yogurt and to the work of Stamen Grigorov, located in the house where he was born. In the museum, if you are visiting Bulgaria, you can learn how to make yogurt at home and a bit more about the history of Grigorov’s discoveries.

We are so proud of our yogurt that many Bulgarians will tell you that ancient Bulgarian tribes were the ones who discovered yogurt by accident. Since Bulgarian tribes were nomadic, they carried the milk in animal skins, which created an environment for bacteria to grow and produce yogurt. This is indeed the way people learned to make yogurt, but it most likely happened in many places independently. Of course, I know many countries make yogurt but I remain proud of all the discoveries that happened in my country (I am saying this because at times I have been judged when I tried to say how important we find the yogurt in Bulgaria and how proud we are).

Yogurt is a tradition in Bulgaria. I don’t know a Bulgarian who does not eat yogurt on a daily basis, up to a few pots per day. And I am not talking about those sweet yogurt products that are made by adding jam or vanilla. I am talking about real, natural yogurt, slightly sourer than most of the products that can be found in the Western world. We add yogurt to almost everything, it is just the perfect addition. It is even the basis of a traditional Bulgarian cold summer soup called “tarator,” made of yogurt, water, cucumber, garlic, and dill. We also make a salad with it called “snezhanka”, and it contains yogurt, cucumbers, garlic, and walnuts. (Recipes can be found below if you want to try something new during the lockdown.) In fact, I am so “addicted” to our yogurt that in every country I go to, the first thing I have do is to find a good yogurt. It took me years to find a good one in Belgium when I lived there (even though one product was labelled ‘Bulgarian yogurt’, it was not the same for sure). In Canada, it was somehow easier. After trying a few different products, it was even faster to find something that I like in the Netherlands, but they have many kinds of milk products. Yet none of them are truly comparable with what you can find in Bulgarian shops. Even the smallest shops have at least 3 to 4 different types because we have a lot of yogurt factories. Every product is different, it has a unique taste and can be made of different kinds of milk.

But honestly, nothing is the same as the homemade yogurt. Many people still make yogurt at home, including my father. I don’t quite remember a time when there was no homemade yogurt on the table at home. It was initially my grandmother making the yogurt and the white Bulgarian cheese (it is nothing to do with Feta but that’s the closest way to explain what it is). So it was somehow logical that my father started making yogurt as well. He knows the technique from his grandmother and grew up with fresh homemade yogurt. My grandparents had a lot of cows, sheep, and goats, so we always had plenty of milk to ferment. Making yogurt at home is so very simple that more and more young people dare to do it. In fact, making yogurt is so easy, I wonder why I am not doing it myself during the lockdown.

How to make it, you may ask?

So you need fresh milk, which my family in Bulgaria currently gets from a local farm. The milk is carefully boiled, and while it is still warm, transferred to a preferable container where you want to make the yogurt. We use old yogurt jars that were very popular before. For some time, my father also used Tupperware, so you can choose anything that you find handy. Before transferring the milk, my father also separates the cream from the milk in a separate jar and uses it to make homemade butter by constantly shaking the jar for around 10 minutes (it is an intensive workout, I tried it a few times!). The biggest problem these days is having a good starter culture so you can begin the milk fermentation. As a starter culture, most of the people, including my father, use a spoon or two of the previous batch of yogurt. So my father never finishes all the yogurt; he always makes sure that there are some leftovers so he can start a new fermentation. He usually adds one tablespoon of the old yogurt to 500 ml warm milk (around 45 C). Of course if the milk is too hot, the bacteria present in the starter culture will die, and nothing will happen. There is also the case that the milk is too cold, and then it will most likely still ferment, but it will have a strange consistency, something between milk and yogurt. If my father is out of old yogurt to start a new fermentation, he usually buys his favorite yogurt from the shop and uses this as starter. Once the jars are filled, he packs blankets all around them to keep the environment warm so the fermentation will begin. From here, you need around 4h to 5h to have a nice homemade yogurt. Simple and straightforward. The next morning you can have a great family breakfast, remembering the old traditions, talking about old memories, passing on the torch to the new generation, and enjoying a healthy start to the day.

The next time you have yogurt, I hope you enjoy it and remember the Bulgarian traditions!

 

Tarator soup recipe:

What you need: 1 cucumber, 250 -300 g yogurt, 1-2 cloves crushed garlic, salt, oil, water, fresh chopped dill. (Most of the ingredients depend on your taste so feel free to add more or less of certain ingredients. Some people also add parsley and walnuts, but it is up to your taste.)

How to make it: Peel and cut the cucumbers into cubes and put them in a preferred bowl; add the crushed garlic, and the minced dill. Beat the yogurt until it turns to liquid and mix it with the rest of the ingredients. Add salt and oil to taste. Add water to make the soup as liquid as you like. Put into the refrigerator to cool it. You can also make it with cold yogurt and cold water. It is perfect for the hot summer days.

Snezhanka (which means “Snow White” in Bulgarian) salad recipe:

What you need: 1 cucumber, 500 g yogurt, 1-2 cloves crushed garlic, 2-3 spoons ground walnuts, salt, oil, fresh chopped dill. (Again, it depends on your taste, if you like more cucumber or yogurt just add more.)

How to make it: First strain the yogurt for a couple of hours, so that all unnecessary water is drained away. Peel and cut the cucumbers into cubes and put them in the bowl. Add the strained yogurt. Add the fresh dill, salt and oil to taste. Sprinkle the walnuts on top of the salad. Perfect for all seasons. If you don’t have a fresh cucumber, you can also use pickles — the final result is also very delicious.

ISAPP’s popular educational videos now feature subtitles in multiple languages

ISAPP’s series of six English-language videos are a useful resource for helping consumers answer important questions about probiotics, prebiotics, and fermented foods. In order to make these popular educational videos accessible to a wider global audience, ISAPP has now updated them with subtitles in multiple languages: Dutch, French, German, Indonesian, Italian, Japanese, Russian, and Spanish.

Dr. Roberta Grimaldi, a principal clinical research scientist who served as ISAPP’s Industry Advisory Committee representative from 2017-2019, led the video subtitling efforts.

“The videos are a good way to communicate information about these products, which are still not fully understood by consumers,” says Grimaldi. She says that while consumers see “a lot of miscommunication and misleading information” online, the easy-to-understand ISAPP videos help bring the scientific perspective to a broad audience.

Multi-lingual members of the ISAPP community stepped up to help with the translations, with Grimaldi managing the task and co-ordinating with the video production agency. She says, “It was definitely an amazing team effort, which I think gave us really great results.”

Science Translation Committee head Dr. Chris Cifelli underlines how worthwhile the video subtitles project has been for ISAPP. “Since ISAPP is an international organization, we have been working hard to make our educational materials accessible to as many people as possible. The subtitles allow the information in these videos to be shared much more widely, ultimately helping consumers make more informed decisions about probiotics, prebiotics, and fermented foods.”

Many of ISAPP’s infographics are also available in multiple languages.

 

How to change the language subtitles on an ISAPP video:

Step 1 – On the ISAPP videos page, click on the video.

Step 2 – Press pause and click the gear-like ‘Settings’ icon, to the right of the ‘CC’ icon.

Step 3 – Click on ‘Subtitles’ and select the language subtitle you prefer.

Step 4 – Resume the video by pressing play.

ISAPP welcomes three new board members

By Mary Ellen Sanders, PhD, ISAPP Executive Science Officer

ISAPP is pleased to announce that Profs. Kelly Swanson PhD, Daniel Tancredi PhD, and Gabriel Vinderola PhD have joined the ISAPP board of directors. The expertise of these three globally recognized academic experts complements that of the current board members, together comprising a leading global group of distinguished scientific and clinical experts in the fields of probiotics, prebiotics, synbiotics, fermented foods, and postbiotics.

Read more about ISAPP’s newest board members:

Kelly Swanson is the Kraft Heinz Company Endowed Professor in Human Nutrition, a professor in the Department of Animal Sciences and Division of Nutritional Sciences and an adjunct professor in the Department of Veterinary Clinical Medicine at the University of Illinois at Urbana-Champaign. He is an expert in the field of fiber and prebiotics, and brings to ISAPP knowledge of application of these substances to companion and agricultural animals. Kelly, who trained with previous ISAPP Board member, George Fahey, is considered one of the top authorities in animal gut health, microbiome, and nutrition. His research has focused on testing the effects of nutritional intervention on health outcomes, identifying mechanisms by which nutrients impact gastrointestinal microbiota, host gene expression, and host physiology. Kelly served on the prebiotic consensus panel (here), led the ISAPP synbiotics consensus panel, and is lead author on the synbiotics outcome paper, currently in press with Nature Reviews Gastroenterology and Hepatology.

Dan Tancredi is a biostatistician with an appointment as an Associate Professor (full professor starting July 1, 2020) in Residence at UC Davis Department of Pediatrics, and is also with the Center for Healthcare Policy and Research. Dan works extensively on NIH-sponsored research and as an NIH scientific reviewer. He has an extensive record of collaboration with ISAPP; he has served as an invited expert and/or speaker at all but one ISAPP meeting since 2009, providing his perspectives on how to improve the quality and scientific impact of probiotic trials and how to conduct systematic reviews that rigorously and transparently synthesize the evidence from these trials. He has been a co-author on 6 ISAPP papers (here, here, here, here, here, here and here), including a 2020 paper “Probiotics as a Tx Resource in Primary Care” published in the Journal of Family Practice (see New publication gives a rundown on probiotics for primary care physicians). Dan was invited to author the Nature commentary on the landmark probiotics trial by Panigrahi, et al. for reducing newborn sepsis in the developing world—showing his reputation as a trusted voice for assessing the quality of probiotic research.

Gabriel Vinderola is a professor at National University of Litoral, Santa Fe, Argentina and Principal Researcher at CONICET, at the Dairy Products Institute (UNLCONICET). He is an expert in lactic acid bacteria, fermented foods, and probiotics. Gabriel has forged academic collaborations with academic and industrial scientists in numerous countries in Europe and with industrial colleagues in Argentina. He has been active in several countries in South America working with regulators to assure that their actions on probiotic guidelines are science-based, including his recent efforts consulting on guidelines for probiotics for the Codex Alimentarius. He has written blogs for ISAPP, translated ISAPP videos and infographics into Spanish, and was an expert on the ISAPP consensus panel on postbiotics. His research has focused on technological aspects of probiotics (biomass production, dehydration, storage, food matrices) and fermented foods. He is an active public science communicator in Argentina on the topics of probiotics, prebiotics, fermented foods, and the microbiome. See Growing interest in beneficial microbes and fermented foods in Argentina for some examples. Gabriel represents the first ISAPP board member from South America and we anticipate his involvement will help ISAPP expand its presence and connections in Latin America.

 

ISAPP partners with British Nutrition Foundation for fermented foods webinar

Did you miss the live webinar? Access the archived version here. Read the speaker Q&A here.

From sourdough starter tips to kombucha flavor combinations – if you’ve checked a social media feed lately, you’ll know how many people are sharing an interest in fermented foods as they self-isolate during the pandemic. And with this rise in popularity comes a host of questions about the practice and the science of fermented foods.

To meet the need for science-based information about fermented foods, ISAPP has partnered with the British Nutrition Foundation (BNF) on a free webinar titled ‘Fermented Food – Separating Hype from Facts.’ The BNF is a UK-based registered charity that brings evidence-based information on food and nutrition to all sectors, from academia to medicine.

The webinar, designed for practicing dietitians and nutrition-savvy members of the public, featured three leading scientific experts who explained the microbiology of fermented foods, the evidence for their health effects, and who might benefit from making these foods a regular part of the diet. Viewers will come away with a clear understanding of what fermented foods are and what evidence exists for their health benefits.

The webinar was held live on Wednesday, July 1, 2020 from 1pm-2pm (BST).

Webinar speakers & topics

 Understanding fermented foods: Dr. Robert Hutkins, University of Nebraska, USA

Exploring the evidence for effects of fermented foods on gastrointestinal health – how strong is it? Dr. Eirini Dimidi, Kings College London

What role can fermented foods have in our diet? A public health perspective, Anne de la Hunty, British Nutrition Foundation

For a quick primer on fermented foods, see the short ISAPP video here or the ISAPP infographic here.

Growing interest in beneficial microbes and fermented foods in Argentina

By Prof. Gabriel Vinderola PhD, Associate Professor of Microbiology at the Faculty of Chemical Engineering from the National University of Litoral and Principal Researcher from CONICET at Dairy Products Institute (CONICET-UNL), Santa Fe, Argentina

Awareness of gut microbes, fermented foods and probiotics has been on the rise in Argentina. Nutritionists and influencers, who in recent years have begun promoting a healthier lifestyle, are leveraging their social networks to post how-to instructions for making fermented foods, advice to promote a ‘healthier’ microbiota, and information on the potential role of probiotics and prebiotics in human health. But are these news items and recommendations based on science? Not always! I’ve been fortunate to have had the opportunity to make sure the science is correctly communicated to a broad audience on the microbiome, fermented foods, probiotics and prebiotics.

In Argentina, for the last 50 years, there has been on the air a TV show with a particular format: the hostess, Miss Mirtha Legrand, invites 4-6 people to have lunch every Sunday, talking about politics, economy, popular culture, arts and even science for 3 hours. According to her, this is the longest continuously running TV program in the world. Every Sunday several thousands of people from Argentina, Uruguay and Paraguay tune in. In October 2019, I was invited to join the table and to comment about the invisible world inside and around us. We discussed how we can profit from bacteria through fermented foods and probiotics, and how to feed our gut microbes with prebiotics. In fact, in 2019, I gave more than 40 talks on this topic to scientific audiences at conferences, as courses for Ph.D. students, as seminars and as workshops. These efforts are targeted not only to local scientists and students, but also to children in schools, local sport clubs in small towns, gyms and hospitals. The interest in friendly bugs is wide-ranging and varied, and fueled by information from radio and TV programs.

“Having lunch with Mirtha Legrand”, a talk show on television for more than 50 years in Argentina, where the discussion on beneficial microbes was brought to the table by Prof. Gabriel Vinderola (far right). Mirtha Legrand, now 93 years old, is in the center (October 3rd, 2019).

The enthusiasm of the audience was immediately evident. Lots of messages came by email, WhatsApp, Facebook or Instagram. People were anxious to know more, inquiring about trustworthy sources to read scientific-based but “easy-to-understand” material, posing specific questions about their gut feelings, where to get these probiotics and prebiotics or how to make fermented foods in a safe manner. Fortunately, the ISAPP infographics on probiotics and prebiotics were already available in Spanish, translated by Miguel Gueimonde (Spain) and me, and these were a welcome resource. Yet people still wanted more information, and asked more and more specific questions.

Spurred by such widespread interest, I contacted a local lawyer-turned-chef, Ana Milena Giacomini, who left behind her professional law career to open a small restaurant with a menu heavily based on fermented foods. She features such delights as home-made yoghurt, chucrut, kimchi, sugary kefir, fermented hummus, sourdough bread, pancakes made out of fermented rice flour, kombucha, kvass and a gasified drink from fermented ginger. With her, we organized 4-hour workshops, which are currently on hold due to COVID-19. These workshops feature Ana preparing some of these fermented foods live, followed by tasting, while I explain the science and microbiology behind them. I share factors related to the identity, safety, stability, and potential health effects of these products. I emphasize the differences between fermented foods and probiotics, while discussing the potential value of incorporating fermented foods, probiotics and prebiotics to the daily diet as a way to promote gut health. I provide more specific information on health effects for which robust meta-analyses are available to support the microbes’ use, such as prevention of antibiotic-associated diarrhea in children, treatment of infant colic, prevention of allergies, and downregulation of intestinal inflammation. Other workshops with different chefs from different locations in Argentina are in line for when the coronavirus pandemic ends.

Part of the four-course dinner containing fermented foods prepared by chef Martin Russo. The starter consisted of fermented carrots and hummus, served on sourdough bread (pictured).

These workshops are expected to be attended by 30-35 people each time. Nutritionists are interested in giving sound responses to their clients, who hear about these topics in the media or in social networks. But also, people come who want to learn how to make fermented foods, where to find probiotics and prebiotics, or to gain clear guidance on how to incorporate live bacteria to their diets. Other health professionals (gastroenterologists, pediatricians), educators and even people from the industry also attend.

 

The dessert was ice cream balls covered by the mother of vinegar (transparent circle on the top), rinsed and sweetened.

Most people interested in attending these workshops have narrow experience with fermented foods, only being familiar with such things as yoghurt, cheese, wine or beer. Some of them do not know that these foods are indeed fermented, or do not have a clear idea what fermentation is about. Most of them also have a very limited awareness, or even misinformation, about probiotics and prebiotics. These workshops offer the possibility for the curious to learn and to taste new foods, to get insights on the science behind fermented foods, probiotics and prebiotics, and to learn the differences between them in a science-based manner in an “easy-to-follow language”. These encounters are a great way to expand the interest by the general public on the invisible world inside and around us.

ISAPP discussion group leads to new review paper providing a global perspective on the science of fermented foods and beverages

By Kristina Campbell, MSc, Science & Medical Writer

Despite the huge variety of fermented foods that have originated in countries all over the world, there are relatively few published studies describing the microbiological similarities and differences between these very diverse foods and beverages. But in recent years, thanks to the availability of high throughput sequencing and other molecular technologies combined with new computational tools, analyses of the microbes that transform fresh substrates into fermented foods are becoming more frequent.

A group of researchers from North America, Europe, and Asia gathered at the International Scientific Association for Probiotics and Prebiotics (ISAPP) 2018 conference in Singapore to discuss the science of fermented foods. Their goal was to provide a global perspective on fermented foods to account for the many  cultural, technological, and microbiological differences between east and west. This expert panel discussion culminated in a new review paper, published in Comprehensive Reviews in Food Science and Food Safety, entitled Fermented foods in a global age: East meets West.

Prof. Robert Hutkins, the paper’s lead author, says the diversity of panelists in the discussion group was an important aspect of this work. “Although we were all connected by our shared interests in fermented foods, each panelist brought a particular expertise along with different cultural backgrounds to our discussions,” he says. “Thus, one of the important outcomes, as noted in the published review paper, was how greatly historical and cultural factors, apart from microbiology, influence the types of fermented foods and beverages consumed around the world.”

The review captures the current state of knowledge on the variety of microbes that create fermented foods: whether these are starter cultures or microbes already present in the surrounding environment (i.e. the ‘authochthonous’ or ‘indigenous’ microbiota). The paper identifies general region-specific differences in the preparation of fermented foods, and the contrast between traditional and modern production of fermented foods—including the trade-offs between local and larger-scale manufacturing.

The authors of the article also took on the painstaking work of cataloging dozens of fermented foods from all over the world, including fermented milk products, fermented cereal foods, fermented vegetable products, fermented legume foods, fermented root crop foods, fermented meat foods, fermented fish products, and alcoholic beverages.

The expert panel discussions held every year at the ISAPP annual meeting provide a much-anticipated opportunity for globally leading scientists to come together to discuss issues relevant to scientific innovation and the direction of the field. This paper is an example of a concrete outcome of one of these discussion groups.

For more on fermented foods, see this ISAPP infographic or this educational video.

Maintaining a family tradition: Bulgarian whole fermented cabbage

By Mariya Petrova, PhD, Microbiome insights and Probiotics Consultancy, Karlovo, Bulgaria

Dr. Mariya Petrova with her father

November and December mark a wonderful time of the year when the cold weather makes you want to stay at home and enjoy homemade foods and drinks. However, the heavy food during the holidays makes all of us think about healthier alternatives and how to keep our gut microbiomes in check. That’s why it can be great idea to supplement your festive menu with fermented foods.

Cabbage ready to be fermented

Partly to have healthier food options at home and partly to engage in longstanding traditions, at this time of the year, millions of people in Eastern Europe roll up their sleeves, get out their knives, salt and large containers, and make fermented vegetables at home. While Western cultures are seeing fermented foods as a trendy health food option, Eastern Europeans have never forgotten how to preserve food by using natural fermentation. In my country of Bulgaria, fermented foods are simply a part of our life. Our most popular fermented foods include whole sour cabbage, pickles and pickled vegetables, yogurt, boza (a special fermented beverage), and fermented apple cider vinegar. We do not take shortcuts by pickling our vegetables with vinegar. Ours is a traditional fermentation process – add salt and then let the natural lactic acid bacteria perform their magic.

Although all of these products are interesting and delicious, the winter season brings to my mind my father’s whole cabbage fermentation. My father is busy with it every year from the beginning of November until mid-December. Whole sour cabbage is a fermented food popular not only in Bulgaria but in many of our neighboring countries such as Serbia, Macedonia, and Romania. Although similar to sauerkraut, Bulgarian whole fermented cabbage ferments the entire cabbage head, not separate cut or shredded leaves. Using whole cabbage requires both an extended period of fermentation time (around 30 to 40 days) and extra care in handling.

Preparing for fermentation

I have pictures etched in my mind of a busy local Saturday vegetable market where people would buy between 30-50 kilograms (sometimes even more) of cabbages for fermentation – depending on the size of their families. These come to life every time I hear “fermented foods” at a conference!

Cabbage and brine

But how do you ferment such a spectacular amount of cabbage? Well, first you need some rather large barrels, of course. Then you remove the outer leaves from the cabbage, core the cabbage heads, and stick them in the barrel. This is not unlike putting together a jigsaw puzzle. The cabbage heads have to be very dense without leaving to much space between them or the fermentation will not work well. The cabbage is then covered with a brine of around 2-4% salt. Finally, something heavy is placed on top of the cabbage. Many people place a heavy rock (clean of course), to keep the cabbage heads under the salty water and to allow them to ferment properly. Packing the cabbage densely and pressing it down is done to reduce oxygen to a minimum, creating an anaerobic environment for the fermentation. For better taste some people optionally add apple, quince, horseradish, and/or beetroot (which also makes the salty water more pink).

Finished fermented cabbage

Every day the salty water has to be inverted which is achieved by flushing it from the bottom of the barrel by using connected vessels and then adding it onto the top. Day-to-day shuffling of the salty water ensures a uniform distribution of microorganisms in the barrel so that all cabbage heads ferment. The best quality fermented cabbage is produced at 12-18°C temperature for around 30 days. This is why the fermentation

is done only in November – to maintain these low temperatures. Temperature from 7.5 to 18°C favors the growth and metabolism of Leuconostoc mesenteroides, while temperatures higher than 20°C favor the growth of Lactobacillus species. At higher temperatures the fermentation process takes shorter time (around 10 days), but the quality of the fermented cabbage is lower. Leuconostoc mesenteroides is essential to start the first fermentation that produces lactic acid, acetic acid, ethyl alcohol, carbon dioxide, and mannitol. All these acids, in combination with aromatic ester alcohol, contribute to the characteristic taste of high-quality sour cabbage.

Following Leuconostoc mesenteroides fermentation, Lactobacillus plantarum takes over lactic acid production, which gives a sour taste to the fermented cabbage. At the end of this Lactobacillus fermentation the cabbage is ready to enjoy as part of traditional Bulgarian cuisine. Like a special gift left by St. Nick, many people use the salted water in which the cabbage was fermenting as a drink, rich in lactic acid bacteria, and said to help digestive health.

Acknowledgment: I thank my father for showing me how to make the fermented cabbage and taking some pictures of the process this year!

Fermented foods on the holiday dinner table

Highlighting the importance of lactic acid bacteria: An interview with Prof. Seppo Salminen

By Kristina Campbell, M.Sc., science & medical writer

 

In a 2009 book called What on Earth Evolved?, British author Christopher Lloyd takes on the task of ranking the top 100 species that have influenced the planet throughout its evolutionary history.

What comes in at number 5, just slightly more influential than Homo sapiens? Lactobacilli, a diverse group of lactic-acid-producing bacteria.

The influential status of these bacteria on a global scale comes as no surprise to Prof. Seppo Salminen, ISAPP president and Professor at University of Turku (Finland), who has spent most of his career studying these microbes. He is the co-editor of the best-selling textbook Lactic Acid Bacteria: Microbiological and Functional Aspects, the fifth edition of which was released earlier this year. Salminen says the scientific community has come a long way in its understanding of lactic acid bacteria (LAB)—and in particular, lactobacilli.

Seppo Salminen at ISAPP annual meeting 2019

“If you think about the history of humankind, earlier on, more than 60% of the food supply was fermented,” explains Salminen. “On a daily basis, humans would have consumed many, many lactic acid bacteria.”

Yet 30 years ago when Salminen and his colleagues published the first edition of the textbook on lactic acid bacteria, they were working against perceptions that bacteria were universally harmful. The science on using live microorganisms to achieve health benefits was still emerging.

“Most people in food technology, they had learned how to kill bacteria but not how to keep them alive,” he explains. “They didn’t yet know how to add them to different formulations in foods and what sort of carrier they need. At that time, the safety and efficacy of probiotics was not well understood.”

Around ten years later, scientists came together to develop a definition of probiotics on behalf of the Food and Agriculture Organization of the United Nations and the WHO (FAO/WHO)—in a report that formed the basis of ISAPP Consensus meeting and today’s international consensus definition: “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”.

With probiotics having been more precisely defined, the following years were a time of rapid scientific progress in the field. Lactobacilli became the stars of the show, as research emerged on the benefits of various strains and combinations of strains in food science and medicine.

Fast forward to today, when rapidly expanding gut microbiome research adds another dimension to what we know about these bacteria. While lactic acid bacteria are still primarily of interest for the health benefits they impart, scientists can now also study their interactions with other microorganisms in the intestinal microbiome. In some cases, this kind of research may help uncover new mechanisms of action.

After everything Salminen and his textbook co-editors (Vinderola, Ouwehand, and von Wright) have learned about lactic acid bacteria over the past few decades, Salminen says there are two main reasons for the perennial importance of the bugs. “One is their importance in food fermentation, extending the shelf life of foods, making a kind of food processing or ‘agricultural processing’ possible. To make sauerkraut shelf-stable for weeks, or to make yogurt or cheese.”

The second reason, he says, relates to their benefits for the host. “Lactic acid bacteria, especially lactobacilli, reinforce intestinal integrity. So they protect us against pathogens; and sometimes against toxins and heavy metals by binding them away.”

He continues, “The more we know, the more we understand that LAB are needed. There are very specific strains that are helpful in different conditions for animal feeds or for clinical nutrition for infants, for example.” He says the knowledge is expanding at such a rapid pace that it may only be a few more years before the textbook he co-edited will need another edition.

Salminen is currently one of the world’s most cited probiotic researchers, and has diverse ongoing research projects related to digestive health, eczema, early life, and nutrition economics—but lactic acid bacteria are the thread that weaves everything together.

“I’m proud to be working on the fifth most important factor in human evolution,” he says.

new_website

ISAPP launches new website, furthering its mission of educating stakeholders on probiotic and prebiotic science

The ISAPP Board of Directors is pleased to announce the launch of the organization’s new website, which has now gone live at ISAPPscience.org. The website has been redesigned for easier navigation by different stakeholder groups—scientists, consumers, clinicians, and students—enabling ISAPP to continue with its mission of providing accurate, science-based information to its readers about probiotics, prebiotics and fermented foods.

ISAPP Executive Science Officer Dr. Mary Ellen Sanders says, “The scientists comprising the ISAPP Board of Directors realize that consumers and clinicians often struggle to find science-based information on probiotics and prebiotics. ISAPP is working to fill this gap, and we have streamlined our website to help individuals from each of these groups easily find the information they’re looking for.”

At the ISAPP annual meeting held earlier this year, advancing probiotic and prebiotic evidence to a variety of audiences was the topic of a special ‘springboard discussion’ session.

“Probiotic and prebiotic science has made significant progress in the past few decades,” says Sanders, “but this progress has not always been communicated effectively or correctly to those outside the scientific community.” Sanders continues, “Some studies describe an expanding array of health benefits but other studies show the limits of these interventions. Our goal is to counter the abundance of misinformation and be the go-to source of accurate materials about probiotics and prebiotics.”

ISAPP is building its capacity to produce more science-focused educational materials tailored to different audiences. Infographics, some of which are translated into 10 different languages, short videos and targeted blogs are featured on the new website. In coming weeks, ISAPP will make additional resources available on the website, including frequently asked questions about probiotics and prebiotics, and a downloadable white paper for clinicians. Signing up for the ISAPP newsletter is the best way to stay up to date on educational materials being added to the website.

New ISAPP video gives an overview of fermented foods and their health benefits

Fermented foods are not the same as probiotic-containing foods. So what’s the difference? Do both of them confer the same health benefits?

These topics are addressed in ISAPP’s latest video, which takes viewers through the scientific basics of fermented foods (see here). Yogurt, kimchi, and cheese fall into this category of foods, which are transformed by growth and metabolic activity of microbes.

Some fermented foods contain live microbes that travel through the digestive tract, interact with cells, and support the intestinal microbiota. Their potential health benefits are of interest, too: not only do fermented foods improve digestibility, but initial studies show they also improve the immune system and prevent acute illnesses.

The upshot? Naturally fermented foods are worth incorporating in your daily diet.

This educational video was commissioned by the ISAPP board of directors with input from several additional scientific experts.

Role of citizen science in research on fermented foods

By Prof. Sarah Lebeer, Universiteit Antwerpen

Spontaneous vegetable fermentations, with their rich flavors and potential health benefits, are regaining popularity among chefs and the general public. Famous Michelin star chefs, such as Belgium’s Kobe Desramaults, have implemented fermented vegetables in their recipes and offer fermented vegetable juices as non-alcoholic alternatives to wine. Serendipity was surely at play when I made contact with Kobe and his team, and had the opportunity to explore the microbial life of many of his fermented food and beverages.

Thanks to this spontaneous collaboration, I became intrigued by fermented vegetables as a promising alternative to dairy probiotic matrices. They have several benefits:

  • they are lactose-free
  • they contain no milk allergens
  • they are naturally vitamin-, antioxidant- and fiber-rich
  • they are vegan, satisfying the growing dietary trend

 

Together with prof. L. De Vuyst – a fermented food specialist from the VUB University in Brussels – we attracted a talented PhD student Sander Wuyts to study Lactobacillus’ role in the spontaneous fermentation process of carrot juices. I admit that fermented carrot juice is not the tastiest beverage I ever drank, but the fermentation process turned out to be scientifically intriguing: it appeared to be a robust, man-made microbial ecosystem dominated by lactic acid bacteria. We now often use this fermentation process in my lab as a model to study various aspects of niche-adaptation and niche-flexibility of lactic acid bacteria (LAB). And if you mix carrot juice with another fresh vegetable juice, such as cucumber, you’ll be surprised by its interesting light acidic flavor!

But perhaps the most rewarding part about our fermented-vegetables project was that we managed to carry out a Citizen Science project with the Flemish name, Ferme Pekes. You could translate it as ‘Fantastic Carrots’ 😊. Forty citizens volunteered to set up their own carrot juice fermentations at home and delivered with great enthusiasm samples of different time points. The carrots originated from their own garden, the supermarket or organic stores. Our analysis indicated that origin or organic compared to conventional product did not impact the microbial community composition. But we also could show that the LABs – first Leuconostoc then Lactobacillus – out-competed the undesirable Enterobacteriaceae after 3 to 13 days of fermentation. Longer times were needed for carrots derived from winter storage.

Our analyses (phylogenetic placement and comparative genomics, which was recently published in Applied and Environmental Microbiology) also indicated that a high LAB diversity was achieved in the different spontaneous fermentations. This is of interest if you believe it is important to let our immune system come into contact with a large and naturally diverse dose of beneficial bacteria. This idea has been promoted through the years as the hygiene hypothesis or microbial deprivation theory and aligns perfectly with the surge of interest in the health benefits of naturally fermented foods. See the recent ISAPP blog from Prof. Colin Hill, who advocates for the idea of a recommended daily allowance of consumption of live microbes.  (See also a related ISAPP blog here.) Such guidelines should be taken with precaution: the fermentations must be done properly with regard to food safety (see ISAPP blog on Making Safe Fermented Foods at Home).

Citizen Science refers to projects where citizens are actively involved in scientific studies, although it has various definitions and descriptions. In our case, it allowed us to obtain a much larger and more diverse set of samples than we could have created in the lab. Furthermore, the opportunity to directly (on e.g. workshops for adults and kids or at delivery of their samples) or indirectly (as a response to articles in the popular press) communicate with citizens helped us greatly in identifying which other research questions might be of importance for the general public. This approach is increasingly implemented in the fermented food and microbiome field. There are examples of fantastic projects such as on sourdough from Rob Dunn, Benjamin Wolfe and colleagues, the Global FoodOmics initiative and the Flemish Gut Flora project, which will also be presented by Dr. Gwen Falony at our next ISAPP meeting in Antwerp. I am not aware of a Citizen Science project in the probiotic or prebiotic area, but it might be a good idea for a joint ISAPP initiative, for science communication, the creation of richer datasets, validation/confirmation of probiotic efficacy, inspiration for future research questions, for example.

2018 Annual Meeting Report Now Available

The meeting report for the Annual Meeting June 5-7th 2018 ISAPP in Singapore is now available, featuring overviews of the speakers and discussion group conclusions.

Two days of plenary talks focused on the latest science featuring prebiotic and probiotic use in: pediatrics, oral health, allergy immunotherapy, the gut microbiome throughout life, synbiotics, liver disease, honey bee health, chronic gut disorders, and more. The meeting also featured an interesting talk about the changes coming in the nomenclature of the genus Lactobacillus.

The plenary, open sessions were followed by a Discussion Forum on June 7th for invited experts and Industry Advisory Committee Members. The discussion groups focused on:

  • Harmonizing Global Probiotic and Prebiotic Food/Supplement Regulation
  • Fermented Foods for Health: East Meets West
  • Potential Value of Probiotics and Prebiotics to Treat or Prevent Serious Medical Issues in Developing Countries
  • Prebiotics as Ingredients: How Foods, Fibres and Delivery Methods Influence Functionality

Finally, there were over 70 posters presented at the meeting featuring the latest prebiotic and probiotic research from around the world.

Slides and abstracts for the meeting can be found on the ISAPP website under the “Annual Meetings” tab, available to meeting participants only.

2018_Singpaore

ISAPP’s First Meeting in Asia is a Huge Success

June 5-7th 2018 ISAPP held it’s first Asian meeting in Singapore. This open registration meeting was a huge success with over 240 attendees from 34 countries.

Two days of plenary talks focused on the latest science featuring prebiotic and probiotic use in: pediatrics, oral health, allergy immunotherapy, the gut microbiome throughout life, synbiotics, liver disease, honey bee health, chronic gut disorders, and more. The meeting also featured an interesting talk about the changes coming in the nomenclature of the genus Lactobaccilus.

The plenary, open sessions were followed by a Discussion Forum on June 7th for invited experts and Industry Members. The discussion groups focused on:

  • Harmonizing Global Probiotic and Prebiotic Food/Supplement Regulation
  • Fermented Foods for Health: East Meets West
  • Potential Value of Probiotics and Prebiotics to Treat or Prevent Serious Medical Issues in Developing Countries
  • Prebiotics as Ingredients: How Foods, Fibres and Delivery Methods Influence Functionality

Finally, there were over 70 posters presented at the meeting featuring the latest prebiotic and probiotic research from around the world.

Next year, ISAPP will be hosting an invite-only meeting in Antwerp, Belgium – May 14-16, 2019. To attend this meeting, join ISAPP as an Industry Member.

      

ISAPP to host live webinar: Microbial metabolism associated with health

Update April 16, 2018:  Recording and slides from the webinar available here.

The International Scientific Association for Probiotics and Prebiotics (ISAPP), in partnership with the International Life Sciences Institute (ILSI) Europe’s Prebiotics and Functional Foods Task Forces, has jointly organized a free webinar, titled Microbial Metabolism Associated with Health. The webinar runs April 12th, 2018 at 15:00 CET, and will highlight recent activities of both ISAPP and ILSI on the beneficial aspects of gut microbial fermentation. The specific focus will be on gut microbiota functions, the effects of the intestinal microbiota on selected nutrients and non-nutrients, and the health benefits of fermented foods. Scientists from both academia and industry may find the webinar of interest. Sign up here.

Webinar participants will learn the status of the science making the links between live microorganisms in the diet and host health. The host gut microbiota is a key factor in determining gut function, nutritional status, biochemical transformations of food and the overall impact on health. This diverse microbial community inhabiting the human gut assists in food metabolism and contributes to the bio-availability of nutrients and non-nutrients; it also has an extensive metabolic repertoire that complements mammalian enzymes in the liver and gut mucosa. Microbial metabolism is an important factor to consider when discussing the management of host health and conditions such as obesity and metabolic syndrome.

The enhanced nutritional and functional properties of fermented foods are being increasingly recognized; not only do microbes transform the substrates and form bioactive or bioavailable end-products, but also, fermented foods contain live microorganisms genetically similar to the strains found in probiotics. The webinar will cover the possible interactions of fermented foods and beverages with the gut microbiota, and potential links to health.

The 90-minute live webinar will be hosted on StreamGo, and will include a question and answer period at the end. There is no cost; however, participants are required to register online beforehand.

Speakers:

  • Effects of the Intestinal Microbiota on Selected Dietary Components
    a) Introduction and Background to the Activity (Dr. Colette Shortt, Johnson & Johnson, UK)
    b) Impact of Intestinal Metabolism and Findings (Prof. Ian Rowland, University of Reading, UK)
  • Health Benefits of Fermented Foods: Microbiota and Beyond (Prof. Robert Hutkins, University of Nebraska, USA)

 

Publications from ISAPP and ILSI-Europe related to the webinar topics:

blog foodomics image

Global FoodOmics: A Crowd-Sourced Window Into Microbes In Our Foods

January 25, 2018. By Mary Ellen Sanders, PhD , Dairy & Food Culture Technologies

Among the factors under our control, diet may be the most important determinant of our gut microbiota. Observations from the American Gut Project suggest that foods containing live microbes increase fecal bacterial diversity, which is generally associated with a healthy gut.

An initiative, Global FoodOmics, was launched earlier this year at the University of California San Diego under the auspices of the American Gut Project to learn more about bacteria in foods and the small molecules they produce. Dr. Julia Gauglitz is the project manager. Food samples (over 2000 have been collected to date) have been analyzed for their small molecule composition and will be tested by 16S rDNA sequencing to determine the bacterial species present. Although currently in its early stages, the aim for this project is to inventory the vast different foods consumed by people around the world.

Although many fermented foods (beer, bread, wine, kefir, many cheeses and others) rely on yeast or molds as fermentation or ripening agents, this project will aim to detect bacterial DNA, but these DNA approaches cannot distinguish between life and dead bacteria.  Labels and other descriptors accompanying submitted food samples may help determine if the species detected are likely to be alive. Fermented foods that retain live bacteria are more likely to influence our colonizing microbiota.

The small molecules being assayed are not limited to the ones produced by microbes. They may be due to microbial growth in the food (by food fermentation microbes or perhaps by spoilage or food poisoning microbes), may be innate to the food, or may be intentional or incidental (e.g., pesticides) additives to foods.

The intent is to turn Global FoodOmics into a crowd-sourced project. It will join the American Gut Project as an avenue for citizens to directly participate in science and enable the project to make all of the data publically available to other researchers and clinicians.

It is notable that this project is not the first attempt to understand the microbial components of food. Food microbiologists for decades have been assaying foods for microbes used to produce food, responsible for food spoilage and linked to food poisonings.  Recently, Prof. Bob Hutkins, University of Nebraska, on behalf of the International Scientific Association for Probiotics and Prebiotics (ISAPP) and with support from the National Dairy Council, embarked on a project to learn the state of knowledge about levels of live microbes in fermented foods. They dug into the published literature and emerged with “A survey of live microorganisms in fermented foods”, In Press at Food Microbiology. This paper gives us a summary of what is known about populations of live microbes in fermented foods, information that is very useful for people wanting to add live microbes to their diet.

Another effort to understand microbes in foods is the Consortium for Sequencing the Food Supply Chain, a partnership between IBM Research and Mars Inc. This project, focused on food safety, aims to develop a baseline of normal microbial communities in foods.

Both Global FoodOmics and the Consortium for Sequencing the Food Supply Chain will leverage modern DNA sequencing technologies to allow us better understand the microbes associated with foods. Global FoodOmics is the first project to understand the microbes and molecules in foods, by pairing small molecule metabolomics measurements with rDNA sequencing.

fermented foods

Fermented foods, health and ISAPP

November 30, 2017. By Mary Ellen Sanders PhD, Executive Science Officer, ISAPP

It seems that fermented foods have arrived. Just within the community of ISAPP board members, fermented foods and their importance to health have been a topic of great interest.  The idea that adding foods containing live microbes may be sound dietary advice has been reflected in many venues and formats, as seen here:

  • Bob Hutkins:
    • Presented “Health benefits of fermented dairy foods: microbiota and beyond” at 5th YINI Summit (Danone Institute) Fermented Foods and Health: The Intersection of Gut Microbiota and Fermentation Microbes on October 18, 2017.
    • Will convene a discussion group at ISAPP 2018 in Singapore “Taking advantage of fermented foods for health.”
    • Submitted a paper on counts of live microbes in fermented foods “A survey of live microorganisms in fermented foods”
    • Along with lead author Maria Marco and others summarized a discussion group on fermented foods convened at the 2016 meeting of ISAPP in Turku, reflected in this popular Current Opijnions in Biotechnology article, Health Benefits of fermented foods: microbiota and beyond.
  • Gregor Reid:
  • Mary Ellen Sanders
  • Seppo Salminen:
  • ISAPP board of directors
    • In 2015, published several comments to the US Dietary Guidelines Advisory Committee, presenting the scientific rational for fermented foods to be part of the US dietary guidelines. See here and here (and for a comment on prebiotic inclusion in dietary guidelines, see here)
    • Oversaw the ISAPP Science Translation committee, which published a consumer-friendly infographic and related materials on Fermented Foods.

ISAPP will continue to work to get this topic recognized by nutrition professionals globally.

salminen and hutkins at YINI

Fermented Foods in Nutrition & Health

November 2017. Discussed at International Union of Nutritional Sciences (IUNS) Congress session. By Prof. Seppo Salminen, Director of the Functional Foods Forum, University of Turku.

Recently, the Yogurt in Nutrition Initiative (YINI) convened a scientific session as part of the International Union of Nutritional Sciences (IUNS) Congress, held in Buenos Aires from October 22-27, 2017. The session focused on how yogurt and other fermented foods affect the composition and activity of the gut microbiota and health. Lectures covered microbiota development in humans, metabolic effects of yogurt and fermented foods, the role of fermented dairy foods on health, and the role of yogurt and fermented foods in nutritional guidelines

Professor Robert Hutkins and I presented at the YINI session. Dr. Hutkins spoke about “Health benefits of fermented dairy foods: microbiota and beyond” and started by defining the role of microorganisms during food fermentations. He then reviewed current research findings on the impact of fermented foods on the human intestinal microbiota. He also distinguished between the microbes that perform the fermentation and those added specifically as probiotics. Although they are often closely related, they are not the same. Both culture-based and molecular methods have shown that although microbes consumed in fermented foods often survive transit, they rarely persist after consumption has ended. Still, they may be able to modulate functional activity in the gut and, in the case of yogurt bacteria, improve tolerance to lactose.

My presentation was titled “Improving your diet with fermented foods: harmonizing dietary guidelines including fermented milks” and I reviewed the role of yogurt in dietary guidelines and recommendations in different countries along with the regulatory status of yogurt and health claims. The talk focused on existing guidelines in Europe; specifically, the live bacteria in yogurt and lactose intolerance claim approved by the European Food Safety Authority. This claim states that yogurt cultures improve lactose digestion (and tolerance) in individuals with lactose maldigestion. Additionally, I suggested that fermented dairy products should be included in dietary guidelines in a more consistent manner, as recommendations currently vary from country to country. A special focus was also given to an Argentinian social program which provides at present over 200,000 school children with locally produced yogurt with a probiotic to improve their health and well-being.

The role of fermented foods and especially yogurt has gained substantial attention among researchers, clinicians, public health workers, and consumers. In addition to the live organisms present in fermented foods, peptides and other metabolites produced by these organisms may also mediate important health benefits. Thus, cultured dairy foods and other fermented products may have important effects on public health and their consumption should be encouraged.

kombucha

Kombucha: Trend or New Staple?

September 2017. By Prof. Bob Hutkins, Khem Shahani Professor of Food Science, University of Nebraska, Department of Food Science and Technology, Lincoln.

This blog post is adapted from a piece published by the Lincoln Journal Star. The article, first published May 4, 2016 and written by Prof. Bob Hutkins, appeared as a response to a reader’s question: “I keep hearing about kombucha… What is this stuff?”

Kombucha (pronounced kom-BOO-chuh) is made by fermenting sweetened tea using a combination of yeasts and bacteria. This mixture of live cultures that starts the fermentation is called SCOBY, short for “symbiotic colony of bacteria and yeast.” The SCOBY takes the form of a gooey mat that can be re-used for each batch or shared with friends.

Kombucha is one of many trendy fermented foods, like kimchi and kefir, that are now found everywhere. No longer just the fare of hipster cafes and posh restaurants, you can find kombucha at your local grocery store—or even at Walmart.

Kombucha’s origins go back at least 2,000 years, to China; the drink gradually spread throughout Asia and Europe. In the U.S., kits for home-brewing kombucha became available to consumers in the early 1990s, and bottled versions soon appeared on grocery store shelves.

Several factors may explain the popularity of kombucha. First, many people like the flavor: uniquely sweet and sour, with a vinegary overtone. Some ethanol (alcohol) may also be present, although commercial products must contain less than the legal limit of 0.5 percent. The fermentation reaction yields carbon dioxide, which gives kombucha a pleasant fizziness. Flavor combinations are endless, from ginger, mango, and blood orange to lavender and cinnamon.

It’s probably the suggested health properties that are most responsible for the kombucha craze. The live cultures in some blends have antimicrobial activity, which may have been valuable in past eras when antibiotics were not available. However, these properties depend on the particular mix of microbes, which varies from batch to batch or brand to brand. Other suggested health benefits range from improved gut health and digestion to treatment of cancer and other diseases. Unfortunately, there is no scientific evidence to support these health claims.

It may be that kombucha is not for everyone—the acidic nature of the drink may not sit well for some people. Microbiologists have also expressed concern that home-brewed kombucha could possibly contain toxin-producing fungi. (See related post on making safe fermented foods at home.)

Nonetheless, there’s no doubt that many consumers are drinking kombucha. Annual sales in the U.S. are over $500 million, with double-digit growth. Around half of the coveted 25-to-34 age group (i.e. millennials) are kombucha drinkers. Yes, it’s popular now, but it also seems that kombucha is likely to be around for a while.

 

Bob Hutkins is the Food Doc. He is a professor at the University of Nebraska-Lincoln, where he teaches and conducts research in food science and food microbiology. Questions on any topic related to food, food safety, food ingredients and food processing can be sent to the Food Doc at features@nulljournalstar.com.

bowl of yogurt with strawberries

Advice from a Nutritionist:  Eat More Fermented Foods.

September 2017. By Christopher Cifelli, PhD, VP of Nutrition Research, National Dairy Council.

Whenever I tell someone that I have a degree in nutrition science, I usually get asked, “Are carbs bad?” or “Should I avoid added sugars?” Rarely do I get asked “What should I be eating more of?” While vegetables, fruits, dairy and whole grains would all be perfectly suitable answers to that question, my go-to response is fermented foods.

Fermented foods have been around for thousands of years. Fermentation is the process of using specific microbes – for example, bacteria, yeast, and molds – to transform one food into another. For example, the fermentation process transforms milk into yogurt. Fermented foods are unique because they can contain live microbes, which can confer health benefits beyond simple nutrition. For instance, did you know that the microbes in fermented foods can help inhibit pathogen growth in the gut? Or, that eating certain fermented foods, such as yogurt, is associated with reduced chronic disease risk?

Government organizations across the globe provide dietary recommendations to help guide people choose the type of foods or diets that promote health. Commonalities include eating more fruits, vegetables, whole grains, beans, legumes and dairy. Another commonality – albeit a disconcerting one – is the lack of a recommendation for consuming fermented foods even though fermented foods, including red wine, kimchi, soya, and yogurt are key parts of healthy diet patterns.

Several recent publications have discussed the need to encourage the consumption of foods that can directly and beneficially impact our gut microbiota to improve overall health (e.g., Bell et al. or Gordon et al.). Identifying and consuming foods that can selectively impact the microbiota to benefit the host health should be a priority.

The time is now. Health professionals should review available evidence to determine how fermented foods fit into dietary recommendations to promote a healthy microbiota. They should encourage the public to increase their consumption of fermented foods to support the health of their microbiota and body. That way, the next time any of us are asked “What should I be eating” we can point to dietary recommendations and say — Fermented Foods!

Read more on fermented foods here and here.

Bacteria illustration

Suggestions for Making Safe Fermented Foods at Home

September 2017 – By Drs. Bruno Pot and Frédéric Leroy, Vrije Universiteit Brussels, Brussels, Belgium.

The impact of lifestyle on the composition and diversity of the human gut microbiota over the last five decades has been tremendous. This is thought to be mainly the result of a cumulative effect ascribed to the increased use of antibiotics and other drugs as well as dietary changes, including consuming less fermented foods that contain live microorganisms.

Fermented foods are important for a healthy diet, as they have the potential to improve the microbiota quality and diversity, are related with reduced disease risk, and can provide essential nutrients.  Consumers are constantly being informed about these benefits, leading to pleas for a return to home-made fermented foods. However, there is rarely mention of the risks that home-made natural fermentations can entail. While making fermented foods at home can be a good idea and help you consume more beneficial microbes, we should realize that the empirical knowhow, skills and equipment to make safe food fermentations may have disappeared over time. This blog is a gentle warning about the possible risks of non-controlled fermentations.

  • Use a starter culture: The use of specific starter cultures at sufficiently high concentration is recommended to properly initiate the fermentation of specific foods and to obtain sufficient control over the process. Relying on spontaneous fermentation (i.e., hoping that environmental bacteria or yeasts initiate the fermentation) increases the risk that uncontrolled fermentations by unsuitable bacteria, yeasts and molds will result in bad or variable quality. In the worst case, dangerous end-products will be obtained.
  • Twice is nice: Starters should not be used repeatedly. Because bacteria multiply several times per hour, their genetic material is changing continuously and the quality of the starter will change over time. It is therefore not a good idea to re-use your ‘old’ product to restart a ‘new’ fermentation all too often, although some fermented food ecosystems such as sourdough or water kefir may usually be ‘backslopped’ frequently. The risks are that off-flavours will be formed or that acidification, which protects your food against the growth of spoilage or pathogenic bacteria, will be too slow.
  • Choose wisely: Not all starters are necessarily safe, although commercially available ones should in principle have been checked for safety (See Helpful Information links below for guidance on findings the right starter). Some yeasts and lactic acid bacteria (LAB) can form compounds (for example, biogenic amines from amino acids) that can result in many health troubles like headache, blood pressure drops, diarrhoea, and even heart problems. You can avoid the production of biogenic amines by using selected starters that do not have the metabolic machinery to make them.
  • To breathe or not to breathe: Some fermentations, like the production of water kefir (usually using dried figs), should be performed in the absence of air and thus require a rubber sealing. For other fermentations, a complete submerging in brine or a covering with oil is necessary. Kombucha, on the contrary, needs a wide opening covered by a cloth that allows oxygen into the vessel. Uncontrolled anaerobic conditions can increase the risk for the growth of clostridia. In cheese making they can be the cause of cheese blowing up, in other conditions they may produce the deadly botulin toxin.
  • Avoid Moulds. Moulds are another problem linked to (too much) oxygen. Moulds can make mycotoxins which can make one very sick and any visible contamination should ring bells! It is not wise to scrape them off, as often they have produced toxins already, left spores or will remain present through their ‘roots’ which most of the time are not visible.
  • Hold the alcohol: During fermentation, sugars are converted to lactic and acetic acids, but also to ethanol. Therefore, the concentration of sugar added may impact the final alcohol levels of the end-product.
  • Pass the gas: In the case of water kefir, the use of a water lock can be necessary, as the CO2 gas which is formed during the fermentation may increase the pressure in the vessel, leading to potential breaking or surprises during opening. Therefore, blown fermented foods products should never be consumed.
  • Party crashers and acid balance: Not all bacteria are your friends. Some undesirables can be present on fresh vegetable products and can in themselves lead to spontaneous fermentation. Therefore, it is important to not let your fermentation be hijacked by these bacteria. The good bacteria should grow and produce acid quickly for a safe fermentation. Pathogens generally cannot grow in high acid environments (below pH 4 is a safe target). This acidity should be reached as quickly as possible during fermentation to avoid the growth of bacteria which can produce toxins or off flavours.
  • Nothing lasts forever: While high acid is essential, it does not protect the food indefinitely. Some yeasts and fungi can grow in high acid. As they grow, some can reduce acidity locally so that (mainly at the surface) other (potentially pathogenic) bacteria can develop
  • Use good quality raw materials. Use only good quality and fresh ingredients when deciding to ferment. While fermentation helps to preserve your fresh foods longer, it will not rescue (almost) spoiled products!
  • Summer and winter milk. If you use milk in your fermentation, it is also possible that the quality of the end product will be different along with the season, as summer milk, harvested from cows in the field, has a different composition from milk harvested from cows fed winterfeed.
  • Temperature. Temperature control is important. While for sauerkraut room temperature 18-22 (65-72°F) is fine, yoghurt fermentation is much better at 37°C (100°F). You, therefore, can expect differences in summer and winter if you do not control the temperature. Find the right spot in the house for both summer and winter.
  • Water activity. In addition to acidification, microbial control is often achieved by reduction of the water activity, generally by sufficient salting and/or drying. This is of major importance to produce fermented sausages. It is important to point out that raw meat is a particularly hazardous matrix, requiring even more care and attention when performed at home.
  • Salt and acetic acid (vinegar) concentration. Both ingredients help keep the pathogens at bay. Stick to recipes that have proven to be reliable.
  • Fermentation time. This is an important factor which can vary a lot and, in turn, impact the quality of your end product. Its critical nature is well known from wine making, in which the duration of the primary and secondary fermentation is well known to be crucial to the quality of the result. While in wine the primary fermentation usually takes between 3 to 7 days, the secondary fermentation can take much longer and will depend on the vial, the alcohol concentration and the yeast used. The fermentation of sauerkraut goes in three stages. ALL three are essential for a safe and tasteful product; a minimum of three to four weeks is necessary. Industrially produced yoghurt can be made in 8 hours, but at home it may take a few hours more. How much more again depends on the milk quality, the starter and the temperature.
  • Do’s and don’t’s: Do invest in a kitchen weighing scale and a thermometer that goes from 0 – 100 °C. Don’t even think about home-made sausage.  Don’t even think about raw-milk cheese.  Do start with simple foods like yogurt or kefir.  There are fool-proof kits for making beer (although they require some hardware).  Sauerkraut and kimchi are relatively easy to make.

Being aware of these simple concepts can help ensure the production of a healthy, tasty fermented food. Consumers should expect that the quality of the resulting fermented food will vary from lot to lot and they should be able to judge when a product is still safe for consumption and when it is not. Consumers should also be aware of the risk factors above and know how to select and handle equipment and execute procedures that will yield safe and nutritious end products.

For additional information:

Fermented Foods on the www.ISAPPscience.org website.

Preparing Fermented Foods and Pickled Vegetables

The University of Georgia Cooperative Extension, the National Center for Home Food Preservation

Safe Preserving: Fermented Foods From the University of Wisconsin Extension