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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:

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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