DN Fermented dairy Dairy Nutrition Forum A PUBLICATION FOR INDUSTRY AND HEALTH PROFESSIONALS
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exploring the health benefits
Volume 11 Issue 1 2019
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Summary points ......................................................... 1 Health benefits of fermented dairy ........................ 2 Dairy news ................................................................... 4 Contact us ................................................................... 4
EDITORIAL As part of the current trend towards fermented foods, there has been a surge in the popularity of various fermented milk products, such as kefir. Fermentation of dairy has been practised for thousands of years and is one of the oldest methods of extending the shelf life of milk. Beyond this, associated health benefits have also been recognised and research continues to deepen the understanding of how these foods impact a range of health parameters. In this edition of DN Forum, scientists from Food for Health Ireland (FHI) explore the role of fermented dairy in health, with an overview of the literature and a synopsis of some novel FHI research in this area. Research into fermented dairy forms one of the key pillars of the new FHI 3 project that was launched this year and is outlined on page 4. We hope you enjoy this edition of DN Forum and look forward to any feedback or comments you wish to share: nutrition@ndc.ie
Summary points •
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Fermented dairy products, such as cheese, yogurt and kefir, have long been recognised for their health benefits. They are produced by the microbial fermentation of milk and several hundred varieties exist depending on the initial substrate, the microorganisms present and the conditions employed. This • gives rise to a variety of textures, flavours, bioactive compounds and an enhanced nutritional composition. The molecules that impart the physiological effects of fermented dairy include vitamins, conjugated linoleic acid, oligo and exopolysaccharides, gammaaminobutyric acid, short-chain fatty acids and bioactive peptides. Consumption of some of these foods can still have a beneficial
impact on the gut microbiome, even when there are no live microbes remaining in the food itself. For example, fermentation of lactose results in the formation of prebiotic oligosaccharides, which can stimulate beneficial bacteria in the large intestine. Most of the health benefits related to fermented dairy are mediated by modulating immune • responses such as inflammation and pathogen defence, mainly through the gut microbiome. Consumption has been associated with reductions in immune dysfunction and pro-inflammatory states, which relate to cancer, type 2 diabetes, cardiovascular disease and obesity. In addition, live yogurt cultures can improve digestion of lactose in yogurt,
Dr Marianne Walsh Nutrition Manager, The National Dairy Council (NDC)
which helps those with lactose intolerance to enjoy the benefits of dairy. Novel research on kefir has improved current understanding of the molecules that are produced during fermentation and their resulting biological impact. Food for Health Ireland researchers are currently exploring how such bioactives may improve glycaemic control and could, therefore, play a role in managing related conditions. www.ndc.ie/health | www.fhi.ie
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Volume 11 Issue 1 | A publication for industry and health professionals
Health benefits of fermented dairy Dr Veronica L. Peterson, Post-Doctoral Researcher, Teagasc Food Biosciences, Moorepark, Co. Cork and Dr Paul D. Cotter, Senior Principal Research Officer and Head of Department, Teagasc Food Biosciences, Moorepark, Co. Cork
Introduction
Fermented dairy is a staple food for many cultures around the world. Indeed, the first record of fermented milk consumption in Ireland dates back to the Neolithic period1. The fermentation of milk began as a means of food preservation by converting carbohydrates, particularly lactose, to lactic acid, which prevents the growth of spoilage- and disease-associated microorganisms. The safe and frequently health-associated lactic acid bacteria (LAB), such as the bacterial genera Lactobacillus, Leuconostoc and Streptococcus, are responsible for this conversion and are typically the dominant microorganisms in dairy fermentations2. Common commercial fermented dairy products available in Europe include cheese, yogurt, kefir, buttermilk, sour cream and crème fraîche. Through this microbial fermentation of milk products, many health-promoting molecules are released, such as vitamins, bioactive peptides and fatty acids. The health benefits from consuming fermented dairy products have been recognised for some time; in the early 1900s, Élie Metchnikoff was one of the first scientists to suggest that yogurt may have health benefits, based on observations of increased longevity in certain Bulgarian populations that consumed high levels3. Research has focused on exploring this phenomenon with the aim of understanding the mechanisms and harnessing the bioactive molecules for their potential use as functional ingredients. Additionally, the growing research of the gut microbiome and its role in health has reinvigorated investigations of the potential biotherapeutic capability of ‘live’ fermented dairy products2,4. Research into the beneficial health effects of fermented dairy products has indicated that they can reduce inflammation and modulate immune response5,6; reduce the risk of cardiovascular disease (CVD) and cancer4,5,6; protect the body against diseasecausing microorganisms2,5; increase the nutritional value of milk and nutrient utilisation5,6; have a beneficial effect on hunger/ satiety signalling hormones and metabolism2,6; and can promote a healthy brain and digestive tract2,6, among other benefits (Figure 1). Bacterial strains associated with fermented dairy have been shown to confer seizure protection in animal models exploring the mechanisms that underly the neuroprotective effects of the ketogenic diet in refractory epilepsy7. Effectiveness of fermented dairy has also been demonstrated in models of weight loss and type 2 diabetes (T2D)2,8.
Immune System B Vitamins5,6 Bacteriocins2,4 Exopolysaccharides2,21-23 Short-Chain Fatty Acids (SCFAs)6,12,13 Bioactive Peptides & Peptides2,4-7,15
Metabolism & Glycaemic Response B Vitamins4,5 Oligosaccharides5,12,13 Octanic Acid15 Bioactive Peptides from Milk2,5,6 Conjugated Linoleic Acid (CLA)2,5,6 Short-Chain Fatty Acids (SCFAs)6,12,13
Brain Health B Vitamins5,6 Iodine Gamma-aminobutyric Acid (GABA)4,5 Short-Chain Fatty Acids (SCFAs)6,12,13 Anti-Inflammatory Bioactives2,5,6 Heart & Cardiovascular Health B Vitamins5,6 Gamma-aminobutyric Acid (GABA)4,5 Short-Chain Fatty Acids (SCFAs)6,12,13 Bioactive Peptides2,5,6
Digestion & Gastrointestinal Health Antioxidants2,5,6 B Vitamins4,5 Oligo & Exopolysaccharides2,5,12,13,21-23 Bioactive Acids & Peptides2,4-7,15 Conjugated Linoleic Acid (CLA)2,5,6 Short-Chain Fatty Acids (SCFAs)6,12,13
Figure 1: Components of fermented dairy and their associated health benefits.
2 www.ndc.ie/health | www.fhi.ie
Dr Veronica L. Peterson
Dr Paul D. Cotter
This article gives an overview of fermented dairy, examining both the existing and emerging research around its impact on health.
Fermented dairy
The nature of fermented dairy products varies depending on the starting product used, which can include cream, whole or reducedfat milk, or result from by-products of other dairy productions, as is the case for buttermilk. There are a wide range of fermented dairy products available globally, but for the purpose of this review, those that are most commonly consumed in Ireland, such as yogurt and kefir, are discussed here (cheese has been addressed in previous editions: Vol 6[2] and Vol 7[3]). Indeed, much of the fundamental knowledge about the health-promoting effects of fermented dairy comes from research on yogurt preparation and consumption9. Commercial yogurt is usually a simple culture of a few LAB, mainly Lactobacillus spp and Streptococcus thermophilus. However, there are a wide range of yogurt preparations available, each with variations in nutritional content and biotherapeutic potential. Buttermilk is a frequently fermented, side-product from butter production and is regarded as a low fat and high nutrient alternative to conventional milk. In Ireland, buttermilk is predominantly used in baked goods due to its high content of lactic acid that reacts with sodium bicarbonate, to create carbon dioxide in products such as soda bread. Kefir is gaining popularity in artisanal and conventional Irish markets. Similar to Metchnikoff’s observations of Bulgarian yogurt, consumption of kefir is traditionally associated with improved health and long life10. Kefir is a unique, fermented dairy product, in part due to its complex microbial composition, containing LAB and yeasts, as opposed to strictly bacterial dairy fermentations. Depending on the initial substrate, the microorganisms present, other ingredients and the conditions employed, different fermented dairy products produce a variety of textures, flavours and nutritional ingredients to suit a variety of tastes and dietary preferences.
Molecules produced by fermented dairy
Microbes involved in fermentations can be rudimentarily viewed as ‘bags of enzymes’, providing a means of controlled microbial growth, which produce compounds that preserve the food, change its taste and enhance the health benefits. Vitamins, conjugated linoleic acid (CLA), oligo and exopolysaccharides, gammaaminobutyric acid (GABA), short-chain fatty acids (SCFAs), and bioactive peptides are all examples of molecules resulting from microbial fermentation of diary11. A summary of health benefits related to these molecules is outlined in Table 1. CLA is created by LAB from unsaturated fats present in milk and confers health benefits, such as anti-inflammatory, antioxidant, and anti-atherosclerotic2,5 properties. Additionally, CLA has been shown to have antihypertensive effects due to angiotensinconverting enzyme (ACE) inhibition2,4. A number of other dairy bioactives, such as GABA, have also been shown to have protective effects, including antihypertensive properties4,5. SCFAs include propionate (conjugate propionic acid), butyrate (conjugate butyric acid), and acetate (conjugate acetic acid). SCFAs have been linked to reduced inflammation12 and reduced risk of human disease, such as colon cancer13. Essential B vitamins present in fermented dairy which are important for overall health include, B12, folate and other conjugates of folic acid, biotin and riboflavin5,6. The molecules produced in fermented dairy products reflect the microorganisms present2. LAB produce lactic acid while Acetobacter are predominantly involved in the production of acetic acid. Lactobacillus, as a frequently dominant LAB, is involved in lactic-acid production, as well as the production of carboxylic acids, esters and ketones. Lactic and acetic acids are the major acids present in dairy ferments and are also major contributors to ferment preservation, as these acids prevent growth of pathogenic bacteria11. Propionibacterium spp. produces propionate, CO2 and
Volume 11 Issue 1 | A publication for industry and health professionals
acetate. The yeast saccharomyces is predominantly attributed to the production of esters that contribute to flavour. In addition to the health-associated compounds referred to above, some flavour molecules produced by the fermentation process are also beneficial to health. Curiously, several molecules associated with an unpleasant flavour are known to have health benefits. Octanoic, decanoic, and nonanoic acids are all associated with a ‘goaty’ or ‘cheesy’ smell14. Octanoic acid (also known as caprylic acid) is linked to satiety/hunger regulation, gastric emptying, weight loss, and is also used as an antimicrobial15. Decanoic (also known as capric or decylic acid) and nonanoic acid have been shown to exert the antiseizure effects associated with the clinical ketogenic diet, which is used for some patients with epilepsy7. Pleasant flavours are also produced from dairy fermentations. These include fruity flavours, such as pineapple (ethyl hexanoate and ethyl butanoate) and banana (3-methyl-butanol and 2-heptanone). Interestingly, 3-methyl-butanol is also one of the flavour components in the highly valued black truffle fungi. Molecule Class
Bioactive Acids
Molecule Name
Associated Health Benefits
Reference
Lactic Acid
Antimicrobial, anti-inflammatory, antioxidant
[2, 5]
Octanic Acid
Hunger/satiety regulation, antimicrobial
[15]
Decanoic & Nonanoic Acid
Antiseizure
[7]
Gamma-aminobutyric Acid (GABA)
Antihypertensive, Anxiolytic
[4, 5]
Conjugated Linoleic Acid (CLA)
Anti-inflammatory, antioxidant, anti-cancer, cardiovascular health, immune regulation
[2, 5, 6]
Bacteriocins
Targeted defense from pathogens
[2, 4]
Bioactive peptides from milk proteins
Antioxidant, immune modulatory, glycaemic & body mass regulation, nutrient absorption, cardiovascular health
[2, 5, 6]
Vitamins
Folic Acid and Folate, B12 (cobalamin), Biotin, Riboflavin
Nutrient utilisation, improved metabolism, glycaemic & body mass regulation, brain and cardiovascular health, essential nutrients for overall health
[5, 6]
Short-Chain Fatty Acids (SCFAs)
Butyrate, Acetate, Propionate
Anti-cancer, anti-inflammatory, gastrointestinal and brain health, reduced risk of cardiovascular disease (CVD)
[6, 12, 13]
Oligo & Exopolysaccharides
Exopolysaccharides
Immune regulation
[2, 21-23]
Oligosaccharides
Promote healthy gut microbiome
[5, 12, 13]
Bioactive Peptides
Table 1: Molecules present in fermented dairy products and their associated health benefits
Overview of health benefits of fermented dairy Pre-digestion
The enzymatic process of microbial fermentation releases molecules that are easily digested, including vitamins, peptides, and organic fatty acids. These enzymatic processes, carried out by bacteria before human consumption, allow easier digestion of nutrients in the gut, and also create bioactive peptides that bind to essential vitamins and trace elements to promote their absorption. Fermented dairy products are also well tolerated by those with lactose intolerance; thus, these products can provide the health benefits associated with dairy to those unable to consume the unfermented product. Furthermore, the European Food Safety Authority (EFSA) has approved the following health claim relating to yogurt with live cultures: ‘Live yogurt cultures can improve digestion of yogurt lactose in individuals with lactose maldigestion’16.
Beneficial fermented products
A considerable amount of research relating to fermented dairy products has shown that consumption of these products can reduce the risk of cardiovascular disease, associated with reduced cholesterol2,4,6. It has also been indicated that fermented dairy may modulate immunological responses2,4,5. This includes not only reducing inflammation, but also contributing to the development of an appropriate immune response against pathogens. Furthermore, consumption of fermented dairy products has been associated with reductions in immune dysfunction and pro-inflammatory states related to cancer, type-2 diabetes, cardiovascular disease, obesity and other diseases2,5,6. Microbes involved in the fermentation of dairy produce antimicrobial and antioxidant compounds that, in addition to protecting the food product from pathogens and toxins2, can also protect the host. Antioxidants are molecules that neutralise
reactive oxygen species (ROS), such as peroxides, to a more stable, less biologically harmful compound. Antimicrobial compounds are major contributors to food preservation and include bacteriocins2. Indeed, selective culturing and evolution of LAB have resulted in the production of safer and healthier food products.
Benefit of live biotherapeutic products in dairy ferments
Although the reported benefits associated with the use of some live biotherapeutics in fermented products is increasing, strict regulation is in place to ensure that these claims are thoroughly validated. Many commercial fermented dairy products undergo a process, such as pasteurisation, which kills the bacterial cultures responsible for fermentation, though live biotherapeutic (probiotic) strains may be added after this process. The EFSA has stated that “live biotherapeutics must survive the gastrointestinal (GI) tract and be resistant to gastric juices, bile, as well as being beneficial to the host, which includes being non-pathogenic, protecting against pathogens, and free of antibiotic resistance genes”. The consumption of fermented dairy can still have a beneficial impact on the gut microbiome, even if there are no live microbes present in the food product. For example, recent research has indicated that the beneficial effects of a ketogenic diet, when used as a clinical intervention to reduce the risk of neurodegeneration, may be mediated through the microbiome17. Molecules produced by dairy fermentation that are not immediately digested can go on to promote the growth of beneficial bacteria in the gut, such as bifidobacterium and akkermansia, which in turn influence host biological processes2,18,19. Akkermansia muciniphila inhabits the mucosal layer close to the intestinal tissue and its presence has been shown to have beneficial impacts on host health7,17,20. LAB fermentation of lactose results in the formation of prebiotic oligosaccharides, such as galacto-oligosaccharide. Such prebiotics in the GI tract are fermented by beneficial bacteria and lead to the production of the aforementioned SCFAs. Some of the antiinflammatory and immune-regulatory effects from fermented dairy are linked to beneficial bacteria in the gut microbiome. Regulatory T cells modulate the immune system and are capable of producing an anti-inflammatory response. Research suggests that gut bacteria influence these immune regulatory cells in the intestine by a mechanism of action through polysaccharide A and SCFAs12,21,22,23.
Novel Irish research Investigations of kefir
Novel Irish research led by Dr Paul Cotter has focused on the microbiology, metabolism and health benefits of milk products, including kefir as a representative fermented dairy product. Recently published work has shown that the flavour created by secondary molecules present in kefir is dependent on the microbes present in the original kefir grain and the stage of fermentation14. Lactobacillus kefiranofaciens is dominant at the early stages of fermentation and is associated with esters and ketones, which give cheesy and fruity flavours. Leuconostoc mesenteroides is more abundant in the later stages and is associated with acetic acid and 2,3-butanedione, which give vinegary and buttery flavours respectively1. Furthermore, it was demonstrated that certain kefir products are capable of reducing weight gain and associated biological measures in rodents fed a high fat diet8. Serum cholesterol was also improved in the rodent model8. This aligns with other research that kefir and kefir-derived peptides are capable of remediating fatty liver disease due to impairments in intestinal permeability related to obesity2,4,6.
Metabolism and glycaemic response
Investigation of how gut microbes alter nutrient availability and host metabolism is one of the key aspects of understanding the role of fermented dairy in glycaemic control. Research into the metabolic effects of the gut microbiome has been explored in diabetes24,25, body weight24,25,26 and exercise27,28. Indeed, certain gut microbes are capable of influencing various metabolic pathways, including neutralisation of ROS7, glycolysis and gluconeogenesis19,24. A new research programme by Food for Health Ireland has spearheaded investigations into the bioactive properties of fermented dairy and how these bioactives may be utilised to improve glycaemic control. This research aims to inform the dairy industry, so that functional products can be designed that could potentially play a role in the reduction of type-2 diabetes and obesity. www.ndc.ie/health | www.fhi.ie
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Volume 11 Issue 1 | A publication for industry and health professionals
Conclusion Fermented dairy has been an integral part of the human diet for thousands of years and evidence continues to support its place as a part of a balanced, healthy diet. Dairy fermentation results in the alteration of biomolecular characteristics of food through microbial-mediated enzymatic processes. LAB fermentation of milk results in enhanced nutritional value and production of bioactive compounds that confer health benefits. Novel research is underway to harness these health-promoting molecules and provide further understanding of the health effects.
References: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Stanley M, Swan R, O’Sullivan A (editors) (2017) Stories of Ireland’s Past: Knowledge gained from NRA roads archaeology (TII Heritage) Dublin: Transport Infrastructure Ireland (TII). Marco ML, Heeney D, Binda S et al. Health benefits of fermented foods: microbiota and beyond. Curr Opin Biotechnol 2017; 44: 94-102. Metchnikoff E. The prolongation of life; optimistic studies. 1908; 234-301. New York & London: GP Putnam’s Sons. Bourrie BC, Willing BP, Cotter PD. The microbiota and health promoting characteristics of the fermented beverage kefir. Front Microbiol 2016; 7: 647. Fernandez M, Hudson JA, Korpela R et al. Impact on human health of microorganisms present in fermented dairy products: an overview. Biomed Res Int 2015, 412714. Ebringer L, Ferenčík M, Krajčovič J. Beneficial health effects of milk and fermented dairy products. Folia Microbiologica 2008; 53: 378-394. Olson CA, Vuong HE, Yano JM et al. The gut microbiota mediates the antiseizure effects of the ketogenic diet. Cell 2018; 173: 1728-1741 e1713. Bourrie BCT, Cotter PD, Willing BP. Traditional kefir reduces weight gain and improves plasma and liver lipid profiles more successfully than a commercial equivalent in a mouse model of obesity. J Funct Foods 2018; 46: 29-37. Parvez S, Malik KA, Ah Kang S et al. Probiotics and their fermented food products are beneficial for health. J Appl Microbiol 2006; 100: 1171-1185. Shavit E. Renewed interest in kefir, the ancient elixir of longevity. Fungi 2008; 1; 14-18. Shah NP. Effects of milk-derived bioactives: an overview. Br J Nutr 2000; 84: S3-10. Smith PM, Howitt MR, Panikov N et al. The microbial metabolites, short-chain fatty acids, regulate colonic Treg cell homeostasis. Science 2013; 341: 569-573. Morrison DJ, Mackay WG, Edwards CA et al. Butyrate production from oligofructose fermentation by the human faecal flora: what is the contribution
14. 15. 16.
17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28.
of extracellular acetate and lactate? Br J Nutr 2006; 96: 570-577. Walsh AM, Crispie F, Kilcawley K et al. Microbial succession and flavor production in the fermented dairy beverage Kefir. mSystems 2016; 1: e0005216. Ghoos YF, Maes BD, Geypens BJ et al. Measurement of gastric emptying rate of solids by means of a carbon-labeled octanoic acid breath test. Gastroenterol 1993; 104: 1640-1647. EFSA Panel on Dietetic Products Nutrition and Allergies (2010) Scientific Opinion on the substantiation of health claims related to live yoghurt cultures and improved lactose digestion (ID 1143, 2976) pursuant to Article 13 (1) of Regulation (EC) No 1924/2006. EFSA Journal 8, 1763. Ma D, Wang AC, Parikh I et al. Ketogenic diet enhances neurovascular function with altered gut microbiome in young healthy mice. Sci Rep 2018; 8: 6670. Cani PD, Neyrinck AM, Fava F et al. Selective increases of bifidobacteria in gut microflora improve high-fat-diet-induced diabetes in mice through a mechanism associated with endotoxaemia. Diabetologia 2007; 50: 2374-2383. Everard A, Belzer C, Geurts L et al. Cross-talk between Akkermansia muciniphila and intestinal epithelium controls diet-induced obesity. Proc Natl Acad Sci USA 2013; 110: 9066-9071. Li J, Lin S, Vanhoutte PM et al. Akkermansia muciniphila protects against atherosclerosis by preventing metabolic endotoxemia-induced inflammation in Apoe-/- mice. Circulation 2016; 133: 2434-2446. Atarashi K, Tanoue T, Oshima K et al. Treg induction by a rationally selected mixture of Clostridia strains from the human microbiota. Nature 2013; 500: 232-236. Round JL, Mazmanian SK. Inducible Foxp3+ regulatory T-cell development by a commensal bacterium of the intestinal microbiota. Proc Natl Acad Sci USA 2010; 107: 12204-12209. Honda K, Littman DR. The microbiota in adaptive immune homeostasis and disease. Nature 2016; 535: 75-84. Ryan PM, Patterson E, Kent RM et al. Recombinant incretin-iecreting microbe improves metabolic dysfunction in high-fat diet fed rodents. Sci Rep 2017; 7: 13523. Plovier H, Everard A, Druart C et al. A purified membrane protein from Akkermansia muciniphila or the pasteurized bacterium improves metabolism in obese and diabetic mice. Nat Med 2017; 23: 107-113. Joyce SA, MacSharry J, Casey PG et al. Regulation of host weight gain and lipid metabolism by bacterial bile acid modification in the gut. Proc Natl Acad Sci USA 2014; 111: 7421-7426. Barton W, Penney NC, Cronin O et al. The microbiome of professional athletes differs from that of more sedentary subjects in composition and particularly at the functional metabolic level. Gut 2017; 67: 625-633. Cronin O, Barton W, Skuse P et al. A prospective metagenomic and metabolomic analysis of the impact of exercise and/or whey protein supplementation on the gut microbiome of sedentary adults. mSystems 2018; 3: e00044-00018.
Launch of FHI 3
New Resource
Food for Health Ireland has just launched the third phase of its research development, FHI-3. Involving a multi-location, multipartnered, multi-disciplinary research centre, the aim of the work is to improve health through innovation in food, primarily dairy. The research focuses on key areas of health such as cardiovascular health, gut health, maternal health and healthy ageing. These are investigated under the categories of dairy fermentates, grass-fed dairy and cheeses.
The National Dairy Council has produced a new consumer booklet on ‘Common Dairy Myths’. The booklet covers a range of topics, addressing misconceptions around nutrition, animal welfare, dairy processing and sustainability. It can be downloaded from www.ndc.ie or a limited number of copies may be ordered by contacting hello@ndc.ie
For more information visit www.fhi.ie
Contact us... The National Dairy Council (NDC)
Food for Health Ireland (FHI)
The National Dairy Council The Studio, Maple Avenue, Stillorgan, Co. Dublin, Ireland +353 (0)1 290 2451 info@ndc.ie | www.ndc.ie
Food for Health Ireland Science Centre South, University College Dublin Tel: + 353 (0)1 716 2391 fhi@ucd.ie | www.fhi.ie
NDCIreland @NDC_ie Mission: To deliver real and unique value to Irish dairy farmers by protecting and promoting the image, quality, taste and nutritional credentials of Irish dairy produce to a wide variety of audiences in a clearly defined, focused and effective manner.
Food for Health Ireland
@fhi_phase3
Mission: To leverage the world-class capabilities of the Irish academic partners, with the market expertise of the industry partners, into a pipeline of innovative, nutritional functional ingredients/products for the global food industry.
While the NDC and FHI have made all reasonable efforts to ensure the accuracy of the information presented in this document, no responsibility is taken by the NDC or FHI for any errors or omissions. The individual views expressed in this publication do not necessarily constitute the views or policies of the NDC or FHI.
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