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Food hygiene importance of zoonoses Salmonellosis

Food hygiene importance of zoonoses Salmonellosis. Ákos JÓŹWIAK Food Hygiene Lectures, 8 th semester. Basic summary. What is Salmonella?. What is Salmonella?. bacterial agent responsible for a zoonotic disease: salmonellosis affecting >100.000 people in EU each year

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Food hygiene importance of zoonoses Salmonellosis

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  1. Food hygiene importance of zoonosesSalmonellosis Ákos JÓŹWIAK Food Hygiene Lectures, 8th semester

  2. Basic summary What is Salmonella?

  3. What is Salmonella? • bacterial agent responsible for a zoonotic disease: salmonellosis • affecting >100.000 people in EU each year • usual symptoms: fever, diarrhea, abdominal cramps • commonly found in intestinal tract of animals • usual sources of infection: eggs, meat from chicken, pigs, turkeys • can be transferred from animals to humans via not properly handled and cooked food Source:

  4. What is Salmonella? • to combat Salmonella, it is necessary to reduce it in animals and derived products • EU Commission adopted an integrated approach: • from farm to fork • situation of Salmonella is monitored at EU level • joint actions already reduced the number of infected humans by 50% in the last 5 years • it is assumed that this is due to effective implementation of control programs in poultry populations Source:

  5. The details What is Salmonella?

  6. Salmonella • Enterobacteriaceae family • large number of different serotypes of the species Salmonella enterica • (to be precise, there are 2 species: S. enterica and S. bongori) • the serovar classification of Salmonella is based on the Kauffman-White classification scheme • serotypes are normally denoted as a non-italicised “species” name, e.g. Salmonella Enteritidis, S. Senftenberg, S. Typhimurium, S. Infantis • rod shaped, Gram negative, non spore forming • motile, flagella in all directions (peritrichous) • exceptions: S. Gallinarum, S. Pullorum, S. Typhi • facultative anaerobes

  7. 3 epidemiological groups • Human typhoid species • typus (S. Typhi) and paratyphus (S. Paratyphi A, B, C) • adapted to humans and does not occur in other animals • Animal typhoid species • causing typhus to different animal species • S. Typhisuis pigs), S. Gallinarum, S. Pullorum (poultry) • does not occur in humans • Enteritis Salmonella (non-typhois species) • facultative pathogens for humans and animals as well • zoonosis • causing paratyphus in animals and salmonellosis in humans

  8. Growth • temperature: • Minimum 7°C, growth greatly reduced at <15°C • Maximum 49.5°C. • Optimum 35-37°C • Some evidence for growth at 5.2°C exists, but this is serotype specific and the data are still not universally accepted. • pH=3,8-9,5 (optimum pH=7-7,5) • water activity: minimum 0.94, optimum 0.99 • atmosphere: can grow in the presence or absence of air • growth under nitrogen is only slightly less than that under air • grows at 8-11°C in the presence of 20-50% CO2 • growth at low temperatures is retarded in the presence of 80% CO2 compared to air.

  9. Survival • known to survive well in foods and on surfaces • Temperature: • survival for >10 weeks in butter held at –23 and 25°C has been noted • salmonellae can survive for 28 days on the surfaces of vegetables under refrigeration • Salmonella can survive for long periods under refrigeration • Water Activity: • survival in dry environments is a characteristic of these organisms • can survive in chocolate (aw 0.3-0.5) for months • exposure to low aw environments can greatly increase the subsequent heat resistance • pH: Salmonella are less acid resistant than E. coli

  10. Inactivation • Freezing: • death occurs during the freezing process, but those that survive remain viable during frozen storage • freezing does not ensure the inactivation of salmonellae in foods • Heat treatment (D-times): • 60°C usually 2-6 min • 70°C usually 1 min or less • Extremely high D times have been reported for experiments with milk chocolate. Values reported were up to 1050 min at 70°C, 222 min at 80°C and 78 min at 90°C. This also applies to other low water content foods • Some rare serotypes (e.g. S. Senftenberg) are significantly more heat resistant than the others, which are not particularly resistant to heat • Water activity: • at water activities less than that allowing growth the decline in numbers is reduced at lower aw values • Preservatives: • growth was inhibited in the presence of 0.1% acetic acid (pH 5.1)

  11. The illness What is Salmonellosis?

  12. Salmonellosis • Incubation: 6-48 hours (usually 12-36 hours) • Symptoms: Diarrhea, abdominal pain, vomiting, nausea and fever lasting 1-7 days • hospitalisationrate estimated at 22.1% • fatality rate 0.8% • Risk Groups: the young, old, and immunocompromised are particularly at risk. In addition people of less privileged socioeconomic groups and those living in higher population densities are more at risk • Long Term Effects: • septicaemiaand subsequent non-intestinal infections can occur • reactive arthritis may occur 3-4 weeks after gastrointestinal symptoms

  13. Salmonellosis • Infective dose: generallyrecognised doses to cause disease at high attack rates are in the range of 105-106cells. • Low attack rates have been observed sometimes (4-6 cells) • Foods with high fat content, like chocolate or peanut butter may protect cells from gastric juices so permitting a lower dose than usual to cause infection. • Treatment: the infection is usually self-limiting although fluid replacement may be required. • Antibiotic treatment seems to be either ineffective or results in relapse or prolonged faecal shedding • Certain groups, e.g. new born children, may benefit from antibiotic treatment.

  14. Sources • Human sources: faeces of infected people contain large numbers of the organism and shedding may continue for up to 3 months. • The median period for shedding is 5 weeks, <1% become chronic carriers • Animal sources: some serotypes are confined to particular animal reservoirs, but many are capable of crossing between species to cause disease in man, often via food. • most Salmonella infections in animals are symptomless • poultry and pigs are regarded as major reservoirs of the organism • animal feeds made from animal products may be contaminated by Salmonella • Salmonella can also be found in fish, terrapins, frogs and birds. • Food sources: • meat or other products derived from infected animals • other animal products, e.g. unpasteurised or re- contaminated pasteurised milk and dairy products, can also act as vehicles • Environmental sources: Salmonella shed in faeces can contaminate pasture, soil and water. • It can survive for months in the soil. • Contamination in the environment can serve to act as a source of infection of other animals.

  15. Salmonellosis Current situation

  16. Status • Out of the about 2500 serotypes, certain ones such as S. Enteritidis (SE) and S. Typhimurium (ST) are responsible for a high number of human disease cases. • Food contaminated by salmonellas are still the major source of human foodborne diseases in the EU • though, in the past 5 years a definite reduction tendency can be seen in the corresponding statistics Incidence of salmonellosis in EU 2004-2008 Source: EFSA Zoonosis report

  17. Number of salmonella species-induced diseases in Hungary (Source: OEK Epinfo, Zoonosis report)

  18. Reducing human salmonellosis • The two main pillars of the Community-endeavour in reducing the number of salmonella-induced human diseases are: • Obligatory salmonella reducing program in the primary production, affecting the stocks • Microbiological standards for the food industry • The aim is to supply the food industry, the catering industry and kitchens with salmonella-free raw material. • An important component of the reduction program is the availability of continuously updated epidemiological data base.

  19. Reducing human salmonellosis salmonella reduction programs in poultry flocks

  20. The beginnings • Monitoring/protection program (SE/ST) has been existing since 1997 in Hungary. • The rules of the early reduction program were issued in an offical guideline („White Book”) • entitled „Integrated quality assurance system against salmonelloses for the poultry sector in Hungary”. • The guideline included the demand for the establishment of a corresponding Hungarian Act in harmony with the related EU Regulation.

  21. Hen breeding flocks • Begining of the National reduction program: 2007 • Sampling bi-weekly • Goal (1003/2005/EC): • The percentage of infected flocks with five indicated serotypes – SE, ST, SI, SH, SV (S. Enteriditis, Typhimurium, Hadar, Infantis and Virchow ) – should have been reduced to 1% until 31 December 2009. • Aim (200/2010/EC): • From 01 January 2010 the aim is still to reduce the infection rate to maximum 1% in adult breeding flocks.

  22. Hen breeding flocks • Based on earlier data, the „initial”estimated infection rate was 6% (SE/ST). • this was reduced to 3% by the end of 2007 • and to 1.44% in 2008 • and 0.4% in 2009. • the infection rate for the 5 main serotypes was 1.6% in 2009 • and for all the serotypes it was 3.4% in 2009

  23. Hen breeding flocks

  24. Hen breeding flocks • The infection rate in Hungary for SE/ST was 0.24% and for the 5 serotypes it was 0.85% by the end of 2010. • The Community aim, therefore was satified. • The infection rate was 2.2% for all the serotypes.

  25. Table egg-producing flocks • A survey in 2006 showed 34% SE/STinfection rate in the Hungarian layer flocks • Begining of the National Reduction Programme: 2008 • Aim (1168/2006/EC): • Only SE/ST • Three times sampling in the production cycle • The limit was set based upon the 2006 baseline study: • The aim for layer flocks was to reach 13.16% SE/ST infection rate by 31 December. • A further goal was to reach 2% infection rate (according to Regulation 1168/2006/EC, section 1. point (1) b).

  26. Table egg-producing flocks • The SE/ST infection rate was 8.66% by the end of 2008. • 1068 stocks were included in the programme. • By the end of 2009, the SE/ST infection rate was 3.16%, • for all the serotypes, it was 7.35%. • Close to 10 million birds were vaccinated (about 100% vaccination rate). • By the end of 2010, the SE/ST infection rate became 1.4% (the related Community requirement was satisfied) • The infection rate for all the serotypes was 5.52%

  27. Table egg-producing flocks The aim for layer flocks was to reach 13.16% SE/ST infection rate by 31 December, 2010 but it was 3.16 % already in 2009. A further goal was to reach 2% infection.

  28. Broiler flocks (Gallus gallus broiler) • Begining of the National Reduction Programme: 2009 • Aim (646/2007/EC): • Only SE/ST • Sampling within 3 weeks before slaughter • The number of SE/ST positive flocks should be reduced below <1% by 31 December 2011. • From the second half of year 2011, food safety limit value will be introduced for fresh broiler and turkey meat

  29. Broiler flocks (Gallus gallus broiler) • About 4000 flocks were included • The SE/ST infection rate was 0.45% by the end of 2009 • and it was 32.9% for all the serotypes. • By the end of 2010, the SE/ST infection rate was 0.08%, thereby the Community aim was satisfied. • The infection rate for all the serotypes was 16.9%

  30. Salmonella prevalence in broiler flocks The aim planned for broyler flocks until 31 December 2011, was fulfilled already in 2009 (0.45 %)

  31. Prevalence of Salmonella in fresh broiler meat (25g sample from the product)

  32. Prevalence data on Salmonella in poultry meat (neck skin samples) 25 gramm pooled-samples from 3 birds’ neck skin

  33. Turkey flocks • Begining of the National Reductionprogram: 2010 • Aim (584/2008/EC): • Breeder turkey • The quantity of SE /ST infected breed-turkey flocks must be reduced below 1% by 31 December 2012 • Sampling: three-weekly • Meat turkey • The ratio of meat turkey infected with SE /ST must be reduced below 1% until 31 December 2012 • Sampling within 3 weeks before slaughter

  34. Data on Salmonella testing in turkey flocks

  35. Prevalence data of Salmonella in fresh turkey meat

  36. The big competition Salmonella vs. Campylobacter

  37. Salmonella spp. and Campylobacter prevalence study of the European Union in broiler poultry at the slaughterhouses • A harmonized Community reduction program must be based on reliable and comparable data • According to Decision 516/2007 EC, the examinations had to be carried out in all Member States applying standardized sampling and examination methods financied by the Community • 26 Member States + Norway and Switzerland • 561 salughterhouses • 10.132 slaughtered items • Execution: 2008 • Evaluation: 2010

  38. Sampling • The sampling pattern was based on the previous year slaughter data • Determination of the prevalence of Salmonella and Campylobacter spp. in slaughtered animal body • neck-skin of the slaughtered bird, this is the best indicator for the potential contamination • presence/absence+ quantitative examination • The survey of the occurrence of Campylobacter spp. in slaughtered flocks • ten pooled appendices samples/slaughter-item • only presence/absence examination

  39. Hungarian results Salmonella vs. Campylobacter

  40. Prevalence of Salmonella spp. in samples, distribution according to serotypes In half of cases, SE occurs altogether with S. infantis

  41. The measure of contamination with Salmonella spp.

  42. Distribution of Salmonella-positive samples according to the type of chilling

  43. Sesonal prevalence of Salmonella and Campylobacter (neck-skin)

  44. EU results Salmonella vs. Campylobacter

  45. Summarised data • More than 5.3 billions of broiler chikens were slaughtered in the Member States in 2008 • UK 816 millions, FR 706 millions, ESP 594 millions • Average Salmonella prevalence: 15.6% (0-85%) • SE+ST: 3.6% (0-9.3%) • The most frequent 4 types SI, SE, S. Kentucky, ST • The Salmonella prevalence (15.6 %) is much lower than the Campylobacter prevalence (75.8%), except in HU • No interrelationship between the prevalance of the 2 causatives was found in the Member States

  46. Salmonella spp. prevalence data in the EU

  47. Comparison of Salmonella prevalence-data obtained at the slaughterhouses and at survey of the flocks

  48. EU survey- conclusions • The Campylobacter contamination both of broiler flocks and of poultry meat is outstandingly high • There is no relationship between salmonella positivity and contamination with campylobacter • Our epidemiological knowledge is still poor, we do not know precisely the points of potential intervention for reducing the prevalence of Campylobacter in the flocks or at the slaughterhouse • At the moment, we do not plan harmonized preventive/reduction program for Campylobacter • The results of examinations clearly indicate that the measure of Campylobacter contamination is varying among slaughterhouses

  49. EU survey- conclusionsII • There is debate on the possible introduction of a quantitative technological criterium (m= 1.000 cfu/g, M= 10.000 cfu/gramm) -this is postponed until the preparation of EFSA opinion (March 2011) • The responsibility of consumers and public caterings in reducing the incidence of both salmonella and campylobacteriosis (careful heat-treatment, prevention of cross-contamination) • The epidemilological status of Member States is very heterogenous • The individual (Member State) regulatory route is open but the Community aim is not modified at the moment (in breeding flocks 5 important serotypes, in the other flock types SE/ST.

  50. Food safety aspects

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