Fermented milk can be defined as the products which are prepared from milk by the action of specific microorganisms known as starter cultures, which results in a reduction of the pH and coagulation of milk. The cultures of microorganisms will be viable, active, and abundant in the fermented milk. Fermented dairy products are of great significance since they provide and preserve vast quantities of nutritious foods in a wide diversity of flavors, aromas, and textures, which enrich the human diet. Today more than 4000 traditional, fermented foods exist worldwide. Fermented dairy products are being prepared since time immemorial, and they have been with us since humans arrived on earth. Fermented milk was developed as a means of preserving nutrients. Dahi, yoghurt, cheese, shrikhand, lassi, Yakult, acidophilus milk, Bifidus milk, skyr, Laben, kefir, kumiss, buttermilk, etc. are some of the examples of fermented dairy products.

Fermented dairy products are foods consumed worldwide and showed a substantial consumption increase in recent years and market trends suggesting that this will even increase. The transformation of lactose into lactic acid is the most important fact, in addition to other bioactive components. There is growing consumer interest in fermented dairy products due to the nutritional and health benefits offered by these products because their effect on the bacterial microbiota of the intestine contributes to a healthy life and increases life expectancy. The trends in the food industry and greater demand for healthy foods have led to the development of products providing functional components, such as prebiotic substances or probiotic bacteria. Dairy products containing prebiotics and probiotics have sparked the interest of the dairy industry due to scientific evidence related to their positive health benefits. The trend in worldwide consumption of fermented dairy products showed a many-fold increase during the COVID-19 pandemic.

Fermentation enhances the nutritional interest of many foods and increases the bioavailability of nutrients. The fermentation by specific lactic acid bacteria (LAB) strains may lead to prevent lactose intolerance and accumulation of galactose. Casein is converted to amino acids and peptides which facilitate its easy digestion. Lactose is converted into oligosaccharides, some of which have prebiotic properties. The most common starter cultures used are Streptococcus thermophilus, Lactobacillus delbruekii, Lactococci, Lauconostock, Bifidobacteria, etc. depending on the product to be prepared. Fermented dairy products could be used on account of their nutraceutical effects:

Proteins: Fermented dairy products are composed of high-quality proteins, such as casein (α-s1, α-s2, β-casein, κ-casein) and whey proteins (β-lactoglobulin, α-lactoalbumin, lactoferrin, immunoglobulins, glucomacropeptide, enzymes and growth factors). Bioactive peptides have immunomodulatory, antifungal, antimicrobial, antioxidant, and anti-carcinogenic activities. Fermentation facilitates increased digestibility and biological value of the protein.

Lipids: Depending on the origin of the milk and the manufacturing process, the lipid content in the fermented products can vary in quantity, but the quality does not change significantly compared to the original milk. The health benefits appear to be attributed to its 25% MUFA and 3% PUFA and are vectors of fat-soluble vitamins A, D, E, and K.

Carbohydrates: Lactose is the main carbohydrate in dairy products which helps lactic acid after fermentation. Depending on the type of product and industrial additives, this disaccharide can reach up to 98% of the total carbohydrates in naturally fermented products. Its hydrolysis is affected by the enzyme β-galactosidase. Fermentation releases oligosaccharides, polysaccharides, and some types of exopolysaccharides (homo and heteropolysaccharides).

Vitamins and minerals: Fermented dairy products are rich in many vitamins and minerals highly bioavailable eg. A, B1, B2, B6, B12, niacin, pantothenic acid, and folic acid, as well as vitamin D, calcium, phosphorus, potassium, magnesium, zinc, and potassium iodide, which have higher bioavailability in the fermented milk products than in raw milk. The lactic acid plays an important role in the absorption of calcium, inhibition of the microbiota pathogenic, and in the stimulation of intestinal secretion.

Numerous health benefits are attributed to the consumption of fermented dairy products, Viz. immunomodulation, anti-allergenic, cholesterol metabolism/angiotensin converting enzyme (ACE) inhibition, wound healing, anti-carcinogenic, antimicrobial, and gastrointestinal health, beneficial in the building of muscle, control on blood pressure and low-density lipoprotein cholesterol, and prevention of tooth decay, diabetes, cancer, and obesity.

Q.2 Where do you see India on a global level in terms of the fermented milk processing industry compared to other countries across the world?

In India, about 10% of the total annual milk production is converted into fermented milk products like dahi in the organized sector while more than 14% of milk is used for these products in the unorganized sector. Fermented milk products such as dahi (curd), Lassi (sweetened yoghurt drink)/chhach (buttermilk), and shrikhand (drained curd added with sugar and flavoring) figure prominently in our regular diet. Dahi is an age-old indigenous fermented milk product of India and has managed its popularity in the Indian diet despite changing lifestyles and food habits. According to the FICCI report (2008), the estimated market size for Dahi in both organized and unorganized sectors is about 200 billion. Methods for the commercial production of dahi have been standardized by several dairy plants in India. The industry continuously looks for improvement and strives for the latest technologies. A huge potential exists, and the Indian probiotic market presents a thriving scene in the near future. Increasing awareness and rural penetration of products can prove to be a winning proposal. Excellent growth opportunities exist for domestic and foreign companies to take advantage of the prevailing situation in the dahi, health, and wellness markets in India.

Q.3 What are your thoughts on the value addition of the fermented milk products viable at the micro-enterprise level?

Traditionally, Indian fermented dairy products like Dahi are prepared by using the previous day’s dahi/buttermilk as the starter culture. But nowadays, the trend of value-addition is swiftly emerging. The use of probiotic starter cultures along with their pure lactic counterparts is inoculated in the prebiotic-fortified milk to convert into symbiotic fermented dairy products.

Prebiotics: It is a component with selective fermentation that produces specific changes in the composition of the gastrointestinal microbiota, as well as in its activity with beneficial effects on the health of the host. The gastrointestinal microbiota produces a selective fermentation of prebiotics which modulates intestinal health through the production of bioactive metabolites, especially short-chain fatty acids (acetate, propionate, butyrate, lactate) which are generated by fermentation of complex carbohydrates. Metabolites of bacterial origin account for about 10% of circulating metabolites, and they have emerged as key regulatory metabolites. These components are non-digestible and selectively stimulate the growth of specific microorganisms.

Probiotics: These are live microorganisms that confer a benefit to the health of the host when administered in adequate amounts. The effectiveness of probiotics is specific to the strain and the specific dose, dispelling the myth that any yogurt can be considered a probiotic. Those who do not have health claims (generally they are considered safe, do not require proof of effectiveness). As a dietary supplement with a specific health claim (define the strain used, evidence-based effectiveness of clinical trials or meta-analysis and use to strengthen the immune system). It was found that probiotics are especially indicated in the prevention of diarrhoea associated with antibiotics, treatment of Helicobacter pylori infection, treatment of pediatric acute diarrhoea, prevention of allergies, treatment of chronic disease irritable bowel syndrome.

Synbiotics: It is a combination of probiotics and prebiotics in the same dairy product. The function of the prebiotic is to improve the survival, growth, and performance of probiotics or other beneficial bacteria in the colon inducing health benefits. Both lactose and exopolysaccharides are known sources of prebiotics.

India’s rapidly advancing probiotic market sees reviews up by 468% in the six months from January to July 2020. This strong engagement moves India to rank 6th globally, ahead of France and Japan as far as e-marketing of probiotic dairy products is concerned. The health claims attributed to these products are the specific driving force in these growth projections.

Q.4 Could you please tell us about some interesting trends that you have observed over time in the fermented milk processing industry and share some insights about the future of this industry?

Worldwide, fermented dairy products are widely consumed and they have shown a substantial increase in consumption in recent years. The market trends suggest that it will increase further. The current pandemic situation and a bit of innovation on the part of dairy processors have combined to build consumer demand in several cultured dairy segments during the past year or so. An emerging trend within cultured dairy is the addition of new health and wellness benefits that are not traditionally found in cultured dairy products. The pandemic has made consumers more focused on the foods they eat, their immune systems, and how food can help with their overall lifestyle. There is growing consumers interest in fermented dairy products due to the nutritional and health benefits offered by these products because their effect on the bacterial microbiota of the intestine contributes to a healthy life and increases life expectancy. The fermented milk market size was valued at $264.77 billion in 2018 and is projected to reach $396.87 billion by 2026, growing at a CAGR of 5.1% from 2019 to 2026.

Probiotic fermented dairy products to combat malnutrition in tribal children: A double-blind, placebo-controlled study was conducted by MAFSU-CDT, Pusad under a UGC’s Career Award Scheme. It involved 120 tribal children of 2-5 years. They were randomly grouped into three, each comprising 40 children. The control group received 200 ml buffalo milk daily, the blank control group received 200 ml dahi and the test group of volunteers received 200 ml probiotic fermented milk for 120 days. The health status, body weight, microflora in the faecal matter were the parameters monitored at an interval of 15 days during the feeding trials and after the termination of the feeding trials. It was observed that there were manifold increases in the healthy microflora in faecal matter, significant weight gain and improved health were evident in all the volunteers under the test group. The study concluded with a recommendation to supplement the regular diet with probiotic products to combat the menace of malnutrition in tribal children.

It is now well confirmed that in addition to lactic acid bacteria, fermented dairy products have bioactive compounds as well as bacteria-derived metabolites produced during fermentation. Fermented dairy products, due to their special characteristics, are an excellent matrix for the incorporation of ingredients and/or nutrients that give the final product properties beyond purely nutritional, making them truly functional foods. Numerous studies and clinical trials with fermented dairy products suggest that they feature health-promoting functions. According to scientific evidence, fermented dairy products are one of the best natural ingredients to be used as an effective treatment that in turn has fewer adverse side effects.

Q.5 What are safety & hygiene standards and regulations that need to be followed in the processing of fermented milk?

Following are the standards and regulations for Fermented Milk including, Heat Treated Fermented Milk, Concentrated Fermented Milk (CAC-CXS 243-2003) adopted in 2003 (Revised in 2008, 2010, 2018):-

Fermented Milk: It is a milk product obtained by fermentation of milk, which milk may have been manufactured from products obtained from milk with or without compositional modification as limited by the provision in Section 3.3, by the action of suitable microorganisms and resulting in the reduction of pH with or without coagulation (iso-electric precipitation). These starter microorganisms shall be viable, active, and abundant in the product to the date of minimum durability. If the product is heat-treated after fermentation the requirement for viable microorganisms does not apply.

Raw materials

• Milk and/or products obtained from milk.
• Potable water for use in reconstitution or recombination

Permitted ingredients

• Starter cultures of harmless microorganisms
• Other suitable and harmless microorganisms
• Sodium chloride
• Non-dairy ingredients (Flavoured Fermented Milks)
• Potable water
• Milk and milk products

Food Additives: Under Section 4.1 of the Preamble to General Standard for Food Additives (CXS 192-1995), additional additives may be present in the flavoured fermented milk and drinks based on fermented milk as a result of carry-over from non-dairy ingredients.

Contaminants: The products covered by this standard shall comply with the Maximum Levels for contaminants that are specified for the product in General Standard for Contaminants and Toxins in Foods and Feeds (CXS 193-1995). The milk used in the manufacture of the products covered by this standard shall comply with the Maximum Levels for contaminants and toxins specified for milk by General Standard for Contaminants and Toxins in Foods and Feeds (CXS193-1995) and with the maximum residue limits for veterinary drug residues and pesticides established for milk by the CAC.

Hygiene: It is recommended that the products covered by the provisions of this standard be prepared and handled following the appropriate sections of the General Principles of Food Hygiene (CXC 1-1969), the Code of Hygienic Practice for Milk and Milk Products (CXC 57-2004) and other relevant Codex texts such as Codes of Hygienic Practice and Codes of Practice. The products should comply with any microbiological criteria established under the Principles and Guidelines for the Establishment and Application of Microbiological Criteria Related to Foods (CXG 21-1997).

The general principles of food hygiene need to be followed by the fermented milk processing units is as prescribed under schedule IV, part III of Food Safety and Standards Regulation 2011.

Q.6 How wastage and economic losses could be prevented in the sector?

Losses of valuable nutrients and waste is a major concern in the Indian dairy industry and globally with dairying activities representing one of the top categories of food lost and wasted. Microbial contamination may occur at various points throughout the production and processing continuum and includes organisms such as gram-negative bacteria and a wide range of fungal organisms. Some of these organisms grow at refrigerated storage temperatures, often rapidly, and create various putrefactive enzymes that result in off-odors, flavours, and body defects (e.g., coagulation), rendering them inedible. Reducing premature dairy food spoilage will reduce waste throughout the dairy continuum.

Strategies to reduce these premature spoilages in the fermented dairy industry include awareness training at grass root level i.e. the milk producers and handlers for reducing raw material contamination on-farm, physically removing microbial contaminants, employing biocontrol agents to reduce outgrowth of microbial contaminants, tracking and eliminating microbial contaminants using advanced molecular microbiological techniques, and others. The fermented milk industry has to follow utmost precautionary measures to check contamination because the starter culture organisms are very susceptible to the attack of spoilage/putrefactive types of organisms. Contamination of raw milk with these organisms leads to failure of the entire batch leading to heavy economic and nutrient losses.

Q.7 According to you, how PMFME Scheme would be able to support micro food processing enterprises engaged in fermented milk processing?

The food processing enterprises engaged in Fermented Milk Processing will be appropriately benefitted through the PMFME scheme under the Aatmanirbhar Bharat Abhiyan. As training for providing capacity building, training support to increase the capabilities of the enterprises, and the upgradation of skills of workers are crucial components under the scheme. The SHGs can be promoted under the scheme towards value-added fermented dairy product production, marketing to profit augment, and sustainable livelihood security.

About the guest

Dr. C. D. Khedkar is an Associate Professor (Dairy Micro) at the College of Dairy Technology in Maharashtra Animal & Fishery Sciences University, Nagpur, Maharashtra. During his PG research, he developed probiotic isolates of L. helveticus strain MTCC 5462 and L. helveticus strain MTCC 5463 capable of surviving and proliferating in the GIT of human beings, the first Indian-origin probiotics registered at CCMB, Chandigarh.

He launched a first-ever project aimed at curbing the menace of mortality and morbidity due to malnutrition in tribal children under the Career Award Scheme for Young Scientists (UGC). His work was recognized by the prestigious Vasantrao Naik Best Research Award for Tribal Development. He has developed a replicable model of Sustainable Dairying for Rural Livelihood Security that has been established in a project village Nandapur.

Dr. Khedkar's 32-year career is ornamented with several national and state-level recognitions including Young Scientist Award (ISCA, 1994), the MAFSU recognized his TRE contribution with the Best Teacher Award (2008), Best Research Worker Award (2009), and Best Extension Worker Award (2010). He is the recipient of the Prof. JP Trivedi Award for his research contribution to the field of probiotics (2013).

Dr. Khedkar has been serving on various learned bodies/associations viz. Academic Council, Board of Studies (in three universities). He is the Founder of Life Member of the Swedish South Asian Network on Fermented Foods (SASNETFF) and Probiotic Association of India (PAi). He is also a Life Member of IDA, ISCA, DTSI, the Association of Indian Microbiologists (AIM), etc.