Recent advances in exploiting goat's milk: quality, safety and production aspects

1. Recent advances in exploiting goat's milk: quality, safety and production aspects Nissim Silanikove, Agricultural Research Organization (ARO), Institute of Animal Science, Israel. Gabriel Leitner, The Veterinary Institute, Israel Uzi Merin, ARO, Israel; Colin .G. Prosser, Dairy Goat Co-operative (N.Z.) Ltd., Hamilton, New Zealand . . .

2. Herding of goats is thought to have evolved about 10,000 years in Persia • Goat milk, and the cheese made from it, were venerated in ancient Egypt with some Pharaohs supposedly having these foods placed among the other treasures in their burial tombs (Smith, 2006). Goat milk continued to play an important role in human nutrition in areas acknowledged as the cradle of modern civilization (Hatziminaoglou and Boyazoglu, 2004).

3. IMAGES OF ANCIENT IRANArsacid (Parthian) Dynasty (248 BCE - 224 CE)METALWORK

4. Magnificent Bronze sculpture of goat: Syria 1200 BC 70 700 BC

5. Goat's milk is the most widely consumed milk in the world

6. Silk Road: goat herdGoat's milk is the most widely consumed milk in the world

8. Goat's milk is the most widely consumed milk in the world

9. Goats cheese are gourmet food Italian Cheeses

10. Gross composition

11. What makes goat milk an attractive option? • High quality source of protein, minerals and vitamins just like cow milk(soy provides protein only) • Differs from cow milk • Casein protein profile better for infant digestion • More medium chain fatty acids, which are easier to absorb • Naturally high in bioactives that are important for infant growth and development

12. Amino acid pattern compared to human milk Goat milk protein has similar amino acid profile to human milk protein Rutherfurd et al (2008) Int J Food Sci Nutr Jun18

13. Casein profile of goat milk • Goat casein profile closer to human milk: • Low levels of αs1-casein • Greater proportion of β-casein • Formation of a finer curd - Easier digestion • Lower allergenic burden

14. Fatty acids in goat milk • More medium chain fatty acids • Have anti-viral activity • Absorbed more rapidly than other saturated fatty acids • Do not form hard stools

15. Goats butter is softer

16. Bioactive Components • Goat milk is a natural source of bioactive components such as: • Nucleotides, • Polyamines, • Free amino acids • These bioactives are all part of the Non-Protein Nitrogen (NPN) fraction of milk • They are the subject of increased interest and research

17. Nucleotides • Nucleotides are building blocks of DNA & RNA • They play a role in gastrointestinal health, maturation and recovery • Considered to be ‘conditionally essential’ for proper development in infants as they cannot synthesize enough for growing tissue • Can be added to infant formula • Total nucleotide levels naturally higher in goat milk than cow milk (absent in soy)

18. Total Nucleotides Prosser et al (2008) Int J Food Sci Nutr 59:123-133

19. Polyamines • Essential for intestinal cell growth and development of digestive capacity • May help to prevent or reduce sensitisation to food allergens • Total polyamine concentration naturally present in goat milk is higher than cow milk

20. Polyamines (Prosser et al 2008, Int J Food Sci Nutr 59:123-133)

21. Free amino acids • Important for gut health and immunity • Taurine • Bile salt formation, • Immune function • Some infants may become deficient in taurine, so is often added to infant formula • Glutamic acid – source of energy for gut • Levels of these amino acids naturally higher in goat milk than cow milk

22. Free amino acids Prosser et al 2008, Int J Food Sci Nutr 59:123-133

23. Nutrient utilisation • Studies show that goat milk fat is utilised more efficiently than cow milk fat • in animals with short bowel syndrome (Alfrerez et al, 2001) • in infants with malabsorption syndrome (Hachelef et al, 1993) • May be due to higher amounts of medium chain fatty acids • These studies suggest that goat milk could be a useful dietary intervention for human malabsorption syndrome.

24. Nutrient utilisation • Similar studies suggest mineral uptake from goat milk greater than cow milk • Calcium uptake and calcium content of femur, sternum and Longissimus dorsi muscle in rats (Aliaga L, et al 2000; Campos et al, 2003). • Uptake and utilisation of iron (Park et al, 1986; Aliaga et al, 2000; Barrionuevo et al, 2002; Alferez et al, 2006), copper (Barrionuevo et al, 2002), zinc and selenium (Alferez et al, 2003) in rats. • Sustains high calcium and magnesium uptake in anemic animals (Nestares et al, 2008) • Bone mineral density in growing pigs (Murry et al, 1998) • Mechanism for this effect is not known

25. Digestibility • Studies show goat milk forms a finer curd than cow milk when acidified in the stomach (Jenness 1980, Haenlein 1992) • Low αs1-casein is considered a key reason for this (Clark & Sherbon, 2000) • NZ goat milk has low αs1-casein • Softer curd thought to facilitate digestion • Almass et al (2006) confirms that goat milk proteins digested faster than cow milk proteins

26. Gut health • Good gut health important for digestion and nutrient absorption • Infant gut is relatively immature and more ‘leaky’ than adult gut • Gut leakiness linked to several disorders, including allergy • Does goat milk enhance gut health?

27. Healthy gut Normal IntestineNormal permeability “Leaky Intestine”Increased permeability Blood Blood

28. Normal diet 7 days +goat milk 7 days Trial Details Treatment Measurements

29. Treatment = heat stress heat = more leaky heat + Goat milk = less leaky Prosser et al, 2004, J Appl Physiol96:650-654

30. Control - healthy Indomethacin + goat milk Indomethacin Intestinal Villi protected by goat milk

31. Auckland infant growth study A randomised, double-blind comparison of goat and cow infant formula Cameron Grant, Barbara Rotherham, Sue Sharpe, Robert Scragg, John Thompson, John Andrews, Clare Wall, Judith Murphy. Dianne Lowry University of Auckland Starship Children’s Hospital, Auckland Sponsored by Dairy Goat Co-operative (N.Z.) Ltd, Hamilton Published in J Pediatrics Child Health, 41, 564-568

32. Results – infant growth

33. Key conclusions • Growth of infants fed goat infant formula is the same as infants fed cow formula • Growth of infants fed goat infant formula is similar to breast fed infants • Tolerability of goat infant formula is similar to cow infant formula • Goat infant formula is a safe and effective source of nutrition for infants

36. Relationships between the conditions of goat's milk production and the contents of some components of nutritional interest in Rocamadour cheese. A. Lucas et al SRR, 2008 - France

37. P.Morand-Fehr, V. Fedele, M. Decandia, Y. Le Frileux: SRR, 2007

38. Milk fatty acid composition of goats grazing on alpine pasture: Žan et al., SRR, 2006 - Slovenia

39. Conclusions • Given free choice, consumption of browse material would be higher in goats than in sheep and cattle, re-emphasizing our null hypothesize that the main advantage of goats over other ruminant species in producing milk rich in valuable nutritional sources relates to its unique feeding habit and high digestion capabilities. • Goats milk on pasture is naturally enriched in fat soluble vitamins, unsaturated fatty acids and CLA, in addition to being naturally rich in medium-chain fatty acids. • Furthermore, goats milk on pasture have an improved profile of medium-chain fatty acids, in comparison to goats fed conventional concentrate-forage diets • High-alpine pasture was shown to be more effective than low-land alpine pasture in this regard. • Thus, milk from goats feeding on pasture may present an overlooked "treasure trove" with respects to its health promoting lipid profile. • However, a deeper understanding of the interactions between lipids and non-lipid components of pasture and milk composition is needed.

40. Goat in a Tree!

41. Goats on scrubland and woodland • Goats are able to consume as much as 10 g/day of hydrolysable tannins and 100-150 g/day of condensed tannins without evidence of toxicity (Silanikove et al., 1996, SRR). • This ability to ingest tannins exceeds the capacity of sheep and cattle, which indeed are not able to survive without considerable supplementation on such grazing land (Silanikove, 2000, SRR; Silanikove et al., 2001, AFST). • Detoxification of tannins by goats is based on enzymatic hydrolysis and depolymerization of the ingested tannins (Silanikove, et al., 2001, SRR). • Thus, theoretically, large amount of hydrolysable and condensed tannins-derived phenols as well as of other types of phenolic compounds are absorbed from the GIT by browsing goats

42. Metabolism of phytochemicals

44. Goats on scrubland and woodland • Plants produce an enormous array of secondary metabolites; many of them has biological effects when comsumed by humans. • In particular, monoterpens were identified as compounds that greatly influence the aroma of milk. • High content of phenols in milk has shown to improve the quality of milk, such as its oxidative stability and the processing efficiency and quality of dairy products. • The results of a few recent studies demonstrate the accumulation of various phenolic compounds in the milk of grazing goats). • Whereas this proposition is still speculative, in our view, goat milk rich in phenolic compounds derived from the diet represents a ‘treasure trove’ of potential opportunities for developing functional foods

45. Issue 2: Food Safety

46. Food Safety • When considering food safety, the major aspects usually thought of are: • i) Milk as a source of infection by zoonoses (defined as pathogens which may be transferred from an infected animal to humans and thereby causes a disease in the infected humans); • ii) Milk as a source of pathogens that produce toxins, thereby, affecting all organisms, including humans; • iii) Milk as a source of undesirable substances from the animal’s diet or inappropriate use of antibiotic, disinfecting and cleansing substances, etc.

47. Food Safety • In Europe and the USA, the main regulatory mean to prevent the occurrence of zoonoses and other pathogenic bacteria and their toxins in marketed goat milk is through bacterial count of the raw milk (Pirisi et al., 2007, SRR). • Based on the potential pathogenic issues (written review) there is a reason to implement more stringent food-safety control system in the dairy goat industry. • Adding the counts of psychrotrophs may be a valuable criterion not only for the evaluation of milk storage conditions, but for the likelihood of its contamination with pathogens. • Another feasible means to improve milk hygiene is to include somatic cell count in milk grading in the form of a payment scheme

48. Milk is a compound liquid that is composed of five physical phases

50. Somatic cells in milk