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Microbial food culture - Probiotics & starter cultures
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Friday, 16 July, 2021, 13 : 00 PM [IST]
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Sanjay Indani & Khushbu Shah
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Microbial food cultures include bacterial food cultures, fungi, and yeast. Bacterial food cultures, which can be subdivided into "starter cultures" and "probiotics." Starter cultures are those traditionally used by the fermented food industry.
The presence of living organisms in traditional fermented foods is well known and has been the subject of scientific inquiry for over a century. The organisms in many cases determine the characteristics of the fermented food - acidity, flavour, and texture, as well as health benefits that go beyond simple nutrition.
These characterising organisms may be present as natural micro-flora of the food, or as a result of the intentional addition of the organisms as starter cultures in an industrial food fermentation process.
Probiotics are usually defined as microbial food supplements with beneficial effects on the consumers. Most probiotics fall into the group of organisms known as lactic acid producing bacteria and are normally consumed in the form of yogurt, fermented milks or other fermented foods. Some of the beneficial effect of lactic acid bacteria consumption include: (i) improving intestinal tract health; (ii) enhancing the immune system, synthesising and enhancing the bioavailability of nutrients; (iii) reducing symptoms of lactose intolerance, decreasing the prevalence of allergy in susceptible individuals; and (iv) reducing risk of certain cancers.
The mechanisms by which probiotics exert their effects are largely unknown, but may involve modifying gut pH, antagonising pathogens through production of antimicrobial compounds, competing for pathogen binding and receptor sites as well as for available nutrients and growth factors, stimulating immune-modulatory cells, and producing lactase.
Food Cultures (FC) are safe live bacteria, yeasts or moulds used in food production which are in themselves a characteristic food ingredient. FC preparations are formulations, consisting of concentrates (> 108 CFU/g or ml) of one or more live and active microbial species and/or strains, including unavoidable metabolites and media components carried over from the fermentation and components (e.g. carbohydrates, organic acids, minerals, vitamins) which are necessary for their survival, storage and to facilitate their application in the food.
FC includes, but is not limited to the terms: starter cultures, dairy starter, yogurt starters, ripening cultures, meat cultures, sausage starter, protective cultures, wine cultures, malolactic cultures, sourdough starter, probiotics, lactic acid bacteria.
Food with added probiotic ingredients is defined as food with live micro-organisms beneficial to human health, which when ingested in adequate numbers as a single strain or as a combination of cultures, confers one or more specified or demonstrated health benefits in human beings.
Role of Probiotics Probiotic helps with preservation of the milk by the generation of lactic acid and possibly antimicrobial compound. The production of flavour compounds (e.g. acetaldehyde in yoghurt and cheese) and other metabolites (extracellular polysaccharides) that will provide a product with the organoleptic properties desired by the consumer. To improve the nutritional value of food, as in, for example, the release of free amino acids or the synthesis of vitamins. It also helps with special therapeutic or prophylactic properties as cancer and control of serum cholesterol levels.
How it Works The digestive process begins as soon as food enters the mouth and to stomach, the microbes present in the GI tract have the potential to act in a favourable, a deleterious or a neutral manner. Microbes in small intestine and in the large intestine complete the digestion process.
Certain intestinal microbes are known to produce vitamins and they are nonpathogenic, their metabolism is non-putrefactive, and their presence is correlated with a healthy intestinal flora. The metabolic end products of their growth are organic acids (lactic and acetic acids) that tend to lower the pH of the intestinal contents, creating conditions less desirable for harmful bacteria. Probiotics may also influence other protective functions of the intestinal mucosa including synthesis and secretion of antibacterial peptides, mucins. The GI tract also serves as a large mucosal surface that bridges the gap between ‘inside the body’ and ‘outside the body’. This interaction serves to prime or stimulate the immune system for optimal functioning.
Composition of Probiotic The most commonly used organisms in probiotic preparations are the lactic acid bacteria these are found in large numbers in the gut of healthy animals and are in the words of the America FDA, Generally Regarded as Safe. Organisms other than lactic acid bacteria, which are currently being used in probiotic preparations, include Bacillus sp., yeasts and filamentous fungi. Probiotic products are now available in different formulations with L. acidophilus, Bifidobacterium longum, Bifidobacterium infantis, Enterococcus faecium and others with or without probiotic and fructooligosaccharides.
These probiotic preparations may be presented in the form of powders, tablets, capsules, pastes or sprays depending on the animal or human receiving the supplement and the condition to be treated.
The selection criteria for lactic acid bacteria to be used as ‘pro-biotic’ include the abilities such as exerting a beneficial effect on the host, withstand into a foodstuff at high cell counts, and remain viable throughout the shelf-life of the product; Withstand transit through the GI tract; adhere to the intestinal epithelium cell lining and colonise the lumen of the tract; produce antimicrobial substances towards pathogens; stabilise the intestinal micro-flora and be associated with health benefits.
Probiotic must have a good shelf-life in food or preparations, containing a large number of viable cells at the time of consumption, and be nonpathogenic and nontoxic in their preparation.
Some of the FSSAI listed probiotic organism includes Lactobacillus acidophilus, Lactobacillus plantarum, Bacillus coagulans, Bifidobacterium bifidum, Bifidobacterium lactis, Streptococcus thermophilus, Saccharomyces boulardii, Saccharomyces cerevisiae.
Food Safety and Standards (Health Supplements, Nutraceuticals, Food for Special Dietary Use, Food for Special Medical Purpose, Functional Food and Novel Food) Regulations, 2016 states that No FBO shall use probiotic ingredients in food except the pro-biotic culture of the microorganisms specified in Schedule VII or those pro-biotic microorganisms approved by the Food Authority from time to time. Pro-biotic preparations may contain added pre-biotic permitted under these regulations. Also stating the labeling requirements regarding misleading claims w.r.t health benefits, label should have ‘Probiotic Food’ written.
EFFCA and the IDF Inventory EFFCA proposed the definition of FC. With the EU Novel Food Regulation from 1997, microorganisms and fungi not yet currently used for human consumption are novel and must be regulated as such.
The inventory was expanded from 113 species in 2002 to 264 species in 2012. A more detailed description of the safety assessment, building of the list, and expected continued updates was published in The IDF Bulletin.
US Regulatory Framework USA has no specific regulation, some species are regarded as “safe & suitable” or human consumption while others have a status as Generally Recognised As Safe (GRAS) and are notified to the Food and Drug Administration (FDA) and published.
The “GRAS self-determinations” are not public, and consequently, no overview is possible. Safe or safety means that there is a reasonable certainty in the minds of competent scientists that the substance is not harmful under the intended conditions of use. There are several differences between GRAS and QPS: • GRAS is for all ingredients • QPS is for micro-organisms only • A GRAS FC is at Strain level & for a particular product • The QPS status applies to the taxonomic unit of a species of microorganisms and not to the product containing the microorganisms.
Microbial food cultures naturally present in fermented foods are not ingredients for the purposes of food labeling. When microbial food cultures are intentionally added to foodstuffs to produce fermented foods, they are considered to be ingredients for the purposes of labeling and may be declared on the product label as “cultured” followed by the name of the substrate. As this is the only instance in U.S. regulations where the common and usual name for microbial food cultures is addressed. It is also common practice in the food industry to list particular organism names (genus and species) on the food label when probiotic bacteria are added to food. A “Partial List of Microorganisms and Microbial-Derived Ingredients That Are Used in Foods” is available on the FDA Web site. FDA states, however, that the list is not comprehensive and does not represent all those microorganisms that may qualify as “harmless lactic acid–producing” bacteria.
Efficacy and safety of probiotics In spite of inherent difficulties establishing good measures of probiotic efficacy on lactose intolerance, diarrhoea and colon cancer show that a daily dose of lactic acid bacteria is needed for any measurable effect Unfortunately, the concentration of probiotics in food products varies tremendously and there are currently no national standards of identity for levels of bacteria required in yogurt or other fermented products. Epidemiological data on the safety of dairy products and a thorough review of the safety data on probiotics suggests no evidence of probiotics being involved with human infections.
However, there always remains the possibility that probiotic consumption can cause infection and that individuals will respond in different ways to a specific strain. The food industry will need to carefully assess the safety and efficacy of all new species and strains of probiotics before incorporating them into food products.
Despite the problems with dosage and viability of probiotic strains, lack of industry standardisation and potential safety issues, there is obviously considerable potential for the benefits of probiotics over a wide range of clinical condition. Ongoing basic research will continue to identify and characterise existing strains of probiotics, identifying strain-specific outcomes, determine optimal doses needed for certain results and assess their stability through processing and digestion.
Over time, new food products containing probiotics will emerge such as energy bars, cereals, juices, infant formula and cheese, as well as disease-specific medical foods. The establishment of standards of identity for probiotic-containing food products will serve to accelerate the development and availability of these food products.
The oral administration of probiotic therapies may be beneficial in a multitude of disorders both inside and outside the GI tract. The direct effects of probiotics in the GI tract are well documented and include up regulation of immune-globulins such as IgA, down regulation of inflammatory cytokines, and enhancement of gut barrier function. The health professional is in an ideal position to guide the consumer towards appropriate prophylactic and therapeutic uses of probiotics that deliver the desired beneficial health effects.
Starter cultures can be defined as preparations with a large number of cells that include a single type or a mixture of two or more microorganisms that are added to foods in order to take advantage of the compounds or products derived from their metabolism or enzymatic activity. Production of fermented foods is, in most cases, based on traditional recipes, indicating that natural and uncontrolled food environment conditions may affect the final characteristics of food.
(Indani is head food safety-regulatory advisor-trainer at SafeFoodz Solutions. Shah is food safety advisor-trainer. They can be reached at safefoodz@gmail.com)
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