1. Valerio Giacconce School of Veterinary Medicine – University of Padua (Italy) Natural casings and food safety: an up-to-date

2. Who I am My name is Valerio Giaccone Full professor of “Meat Hygiene and Food Inspection”

3. Who I am My Collegues say I am … … the “Food detective”

4. Who I am I would like to be called … … the “Food Doctor”

5. As Doctor … … I should make everything to keep the food “safe” … … and keep away every possible “hazard”

6. Arguments What we know on casings What we should better understand What we should discover

7. What we know on natural casings?

8. We know that … … natural casings are worldwide used as “skin” … … for various kind of sausages and other foods

9. We know that … … the commercial trade of natural casings on the world … … plays a considerable economic role

10. Houben (2005) “In 2002 the total EU foreign trade in natural casings … … was about 1.4 billion dollars”

11. Koolmees (2004) He reports that the trade of natural casings … … is estimated in 2.5 billion dollars per year

12. We know that … … the 60% of natural casings used for sausages … … comes from the small intestine of sheep

13. Natural casings … … are drawn from the submucosa of animal gut … … by desliming and stripping off their mucous and muscular layers

14. Natural casings … … are usually prepared by salting, curing and drying … … various part of animal gut

15. Hazards for human health

16. First HAZARD and RISK … … ARE NOT THE SAME THING

17. An hazard … … is a physical, chemical or biological agent … … which can be dangerous for human health

18. An hazard … … is always an hazard … … aside from the food

19. For example Ice cream contains a lot of air (and of Oxygen) Clostridium botulinum grows only in strict anaerobiosis

20. For example Clostridium botulinum is an hazard for ice cream ? YES, because it can cause botulism in humans

21. Nevertheless … … the probability that C. botulinum grows in ice cream … … is very low, because the presence of too much oxygen

22. The risk A risk is the mathematical probability … … that an hazard can occurr

23. Kind of hazard Chemical residues Microbial pathogens

24. Microbialhazards Viruses Bacteria Toxigenicmoulds

25. Chemicalhazards Xenobioticcontaminants Naturalcontaminants

26. Microbial pathogen Salmonella enterica Campylobacter Listeria monocytogenes Escherichia coli VTEC

27. Chemical residues Heavy metals Antibiotics & chemoterapics Pesticides Mycotoxins (ochratoxin)

28. Microbial pathogen In 2009 in European Union occurred more than … … 190.000 cases of human foodborne campylobacteriosis

29. Microbial pathogen In 2009 in European Union occurred more than … … 108.000 cases of human foodborne salmonellosis

30. Microbial pathogen In 2009 in European Union occurred … … 1.645 cases of foodborne human listeriosis

31. Foodborne diseases 2009 The EU Summary Report “Trends and Sources of Zoonoses and Zoonotic Agents and Food-borne Outbreaks in 2009”

32. What we know Natural casings are not a substantial source … … of foodborne pathogens for sausages

33. As consequence Natural casings are microbiologically fully acceptable … … if they are adequately dry-salted

34. What we know Very rarely natural casings harbor Salmonella, … … Listeria monocytogenes or other microbial pathogens

35. Why ? Because their production process and … … because the antimicrobial action of salting and curing

36. The pathogens They are normally harbored in gut of animals, so they … … could pass to natural casing in the first production steps

37. But … … … by salting, curing and drying the gut for at least 30 days … … it is very rare that Salmonellae and other pathogens can survive

38. Clostridia Sulphite-reducing Clostridium are sometimes detected in natural casings They produce high resistant “spores” which survive in salt

39. Bacillus The same risk can occorr with spores of Bacillus cereus … … another cause of foodborne intoxication

40. Nevertheless … … the risk for sausages … … comes from the alive clostridia, NOT from spores

41. We know that … … the alive Clostridia CAN NOT grow in natural casings … … because their salt content

42. An experience of challenge test

43. Aim of the study Inspired by Bailocom, we have performed a challenge test … … to study the behaviour of Clostridia in natural casing

44. The numbers We have analysed 120 samples of natural casings … … looking for the charge of sulphite-reducing Clostridium

45. The numbers The 30 casing in which we found the most high charges of Clostridium … … were then used to produce raw seasoned sausages

46. The tests 21 sausages at the begin of seasoning and other … … 21 sausages at the end of seasoning were analysed

47. The results In all samples tested we have found charges of Clostridium … … always below 10 cfu/g of meat

48. What does it means? Natural casing can contain low charges of Clostridium spores … … but the spores have no real significance for the sausage

49. What we should better understand

50. Viruses Certain viruses, pathogenic for breeding animals, may persist … … in adequately salted casings

51. Viruses Cattle and sheep’s gut can harbor infectious viruses … … of Foot and Mouth disease

52. Viruses Pig gut can harbor infectious viruses of … … Classical Swine Pest Virus (Hog cholera virus)

53. It is possible … … to treat natural casings with anti-viral compounds These treatments can inactivate the pathogenic viruses

54. Treatments They are based on lactic acid or citric acid … … and also on orthophosphates

55. Effectiveness At today it seems that these treatments are effective … … to inactivate pathogenic viruses, but …

56. … but … … we must take high care to the rinsing of casings … … after the treatment

57. The rinsing It is probable that a rinsing of only 3 hours … … it is not sufficient to wash away all residues of additives

58. Instead … … a rinsing of 16 hours seems to be sufficient … … to wash away all residues of acid or basic additives

59. TSE risk In bovine and sheep gut could be present prions of … … transmissible spongiforme encephalopathies (BSE/scrapie)

60. TSE risk In the EU no casings are made from native-born cattle … … because cattle intestine is a specified risk material (SRM)

61. TSE risk Natural casings derived from sheep and goats can harbor.… … the causative agent of scrapie

62. We know that … … most TSE infectivity resides in the mucosa … … particularly in the lymphoid nodules (s.c. Peyer’s patches)

63. Lymphoid nodule (Peyer’s patch)

64. Natural casings Because the severe process of desliming and stripping … … they ARE NOT particularly at risk to harbor TSE prions

65. What we should discover on natural casings?

66. Chemical residues They are a real “black hole” There is a quite complete lack of scientifica data

67. Chemical residues Pharmacological treatments are regularly performed … … in reared animals (antibiotics, chemotherapics …)

68. Chemical residues Other chemical residues can be present in gut content … … because they come from feed and environment (heavy metals)

69. In theory … … residues of all these contaminants could be present … … also in natural casings

70. In literature We have only a report about the persistance of residues … … in natural casings

71. At today … … we DO NOT have scientific data about the real amount … … of antibiotics, heavy metals and/or pesticides in casings

72. Personally … … in this last month I began to perform some analysis … … looking for heavy metals and ochratoxins in natural casings

73. I hope … … You will substain my effort … … to obtains sufficient scientific data in this research

74. In conclusion Remember that … … an hazard is always an hazard What is important is the RISK, i.e. the probability of an hazard

75. In conclusion It is quite probable that natural casing are products … … with a very low risk for human health, but …

76. … but … … it needs to demonstrate this low risk … … from a scientific point of view

77. … for Your attention!