Listeria monocytogenes in food as public safety risk

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Listeria monocytogenes in food as public safety risk

  1. 1. European Symposium on Food Safety 21-23 May 2012 Grzegorz Madajczak, Ph.D. DVM gmadajczak@pzh.gov.plNational Public Health Institute – National Institute of Hygiene
  2. 2. Present, that Listeria monocytogenes it is not only the food quality / safety criterion, but first of all public health risk.2012-05-27 National Public Health Institute – National Institute of Hygiene 2
  3. 3. • Gram(+) bacteria.• Regular, short rods with rounded ends.• Facultative anaerobes.• Can grow at refrigeration temeratures to significant numbers (in sufficient time).• Resistant for low pH. The image source: http://www.sciencephoto.com/2012-05-27 National Public Health Institute – National Institute of Hygiene 3
  4. 4. • The primary reservoir for L. monocytogenes is soil, water and forage, mud, and silage.• Additional reservoir is alimentary tract of domestic and wild animals.• Source of bacteria are infected animals.• Consumption of contaminated food is main route of infection for human.• Infectious dose was determined as 107 CFU. Other papers suggest even 100 CFU. The image source: http://emedicine.medscape.com/article/965841-overview 2012-05-27 National Public Health Institute – National Institute of Hygiene 4
  5. 5. • Infectious disease, caused by Listeria monocytogens. • Especially danger for some groups of people (high risk groups): – Neonates, – Pregnant women, – Immunocompromised people, – Elderly (60.2 % of cases in 2010 occurring in individuals over the age of 65).2012-05-27 National Public Health Institute – National Institute of Hygiene 5
  6. 6. 12001000 800 High number of Female 600 pregnancy associated cases Male 400 200 0 <1 1-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+ Data Source: ECDC TESSY2012-05-27 National Public Health Institute – National Institute of Hygiene 6
  7. 7. Reservoir Source Vehicle Transplacentar infections2012-05-27 National Public Health Institute – National Institute of Hygiene 7
  8. 8. • L. monocytogenes is frequently present in raw foods of both plant and animal origin.• Can be endemic in food processing environment.• Present in food retail environment and houshold.2012-05-27 National Public Health Institute – National Institute of Hygiene 8
  9. 9. • Notificable disease.• Varied clinical forms are described: – Sepsis, – CNS infections, – Endocarditis, – Localised infections, – Pregnancy associated infections2012-05-27 National Public Health Institute – National Institute of Hygiene 9
  10. 10. • Usually self-limiting febrile gastrointestinal disease presenting with unspecific symptoms like: – Nausea, – Vomiting, – Diarrhea.• Observed as sporadic cases and food-poisoning outbreaks. 2012-05-27 National Public Health Institute – National Institute of Hygiene 10
  11. 11. • Study conducted by Walter F. Schlech III in 2002 in Canada. 13 2 1• Material: stool spec. from 7775 18 4 diarrhea cases.• Only 18 cases were caused by 140 L. monocytogenes. L. monocytogenes L. innocua• L. monocytogenes could cause 137 L. welshimeri L. grayi the sporadic gastroeteritis, but other Listeria it is not importanant pathogen Salmonella sp. Campylobacter sp. in such cases. Schlech et al., CID 41 (2005), 778-784 2012-05-27 National Public Health Institute – National Institute of Hygiene 11
  12. 12. Food-borne outbreak: „an incidence, observed undergiven circumstances, of two or more human cases of thesame disease and/or infection, or a situation in which theobserved number of human cases exceeds the expectednumber and where the cases are linked, or are probablylinked, to the same food source”.(Directive 2003/99/EC)Food vehicle: food (or foodstuff) that is contaminated bya causative agent.(EFSA, Manual for reporting of food-borne outbreaks […]) 2012-05-27 National Public Health Institute – National Institute of Hygiene 12
  13. 13. Listeria monocytogenes is absolute foodborne pathogen, caused both: gastrointestinal and invasive listeriosis. All listeriosis outbreaks should be classified as foodborne or at least waterborne.2012-05-27 National Public Health Institute – National Institute of Hygiene 13
  14. 14. Country Year Food vehicle AffectedFrance 1999-2000 Pork tongue in jelly 26 casesUSA Mexican-style cheese made 2008-2009 8 pregnant women(multistate) from pasteurized milkCzech Rep. 2006 Local cheese 75 casesCanada, 14 pregnant women, 2 babies born to 2008 Pasteurized milk cheeseQuebec asymptomatic carriersAustria,Germany, 2009 Acid curd cheese “Quargel” 14 cases, 4 deathsCzech Rep.USA, 2010 Hog head cheese 14 cases of invasive listeriosisLouisianaUSA 2011 Cantaloupe (Rockmelon) 84 people, 15 deads(multistate) • In 2012 year 37 alerts were notified in RASFF • In 2011 year 106 alerts were notified in RASFF 2012-05-27 National Public Health Institute – National Institute of Hygiene 14
  15. 15. • Case classification: illness occurred in a pregnant woman or an infant aged <28 days. • Woman has unspecific flu-like symptoms. • CNS infection are very rare in pregnant women. • Outcome depends on stage of pregnancy. I trimester II trimester III trimester Miscarriage Stillbirth Preterm birth Congenital listeriossis2012-05-27 National Public Health Institute – National Institute of Hygiene 15
  16. 16. • Depending on time of clinical symptoms manifestation, two types of infection are recognized Early-onset Late-onset Associated with prematurity and Caused by bacteria acquired acquired throw utero. from vaginal tract of asymptomatic mothers Clinical symptoms occurs just Occurs about 2 weeks post after birth (mean-time is 1.5 partum. day) Sepsis Meningitis 2012-05-27 National Public Health Institute – National Institute of Hygiene 16
  17. 17. • Characterization of listeriosis severity depends on category of disease (invasive / non-invasive).• Low occurrence contrasts with high case-fatality rate (ranging 20- 30%).• Up to 11% of neonates and 30% survivor of CNS infections suffer residual symptoms.• Psychiatric squeals have been also reported.• Losing pregnancy• Neonatal deaths2012-05-27 National Public Health Institute – National Institute of Hygiene 17
  18. 18. Number of RASFF alerts in 2010 year 2% 2% bivalve molluscs and products thereof 4% 3% crustaceans and products thereof 14% fish and fish products gastropods 16% meat and meat products (other than poultry) 58% milk and milk products1% poultry meat and poultry meat products prepared dishes and snacks2012-05-27 National Public Health Institute – National Institute of Hygiene 18
  19. 19. 1700 0.35 0.36 0.37 0.4 0.34 1650 0.3 0.35• The EU/EEA rate of 1600 1550 0.3 0.25 confirmed human 1500 1654 0.2 1450 1597 1637 0.15 cases of Listeria 1400 1581 0.1 infection has been 1350 1425 0.05 1300 0 relatively stable in 2006 2007 2008 2009 2010 the last four years. No of cases Notification rate• Listeriosis had the highest impact among the elderly (65+) with the highest confirmed case rates and high mortality. Data Source: ECDC TESSY 2012-05-27 National Public Health Institute – National Institute of Hygiene 19
  20. 20. Listeriosis cases in 2010 by country400 390350 312300250200 176150 129 95100 72 71 63 62 59 40 35 29 50 22 20 11 10 10 7 6 5 5 5 4 1 1 1 0 DE FR UK ES IT NL FI SE DK PL BE AT CZ NO HU SI GR IE LV RO EE LT SK BG CY IS MT Data Source: ECDC TESSY 2012-05-27 National Public Health Institute – National Institute of Hygiene 20
  21. 21. 80 Listeriosis cases 0.17 0.17 0.260 0.11 0.15 0.09 0.0940 0.058 0.058 0.1 62 6420 22 28 43 33 33 0.05 0 0 2005 2006 2007 2008 2009 2010 2011 Cases Morbidity per 100 00010 Neonatal listeriosis 1.94 2.5 8 1.44 1.45 2 1.29 6 1.5 0.84 4 8 1 0.27 5 6 6 2 3 1 0 0.5 0 0 2005 2006 2007 2008 2009 2010 2011 Neonatal cases Morbidity per 100 000 of births Data Source: Infectious diseases and poisonings in Poland http://www.pzh.gov.pl/oldpage/epimeld2012-05-27 National Public Health Institute – National Institute of Hygiene 21
  22. 22. • EU Regulation No 2073/2005 lays down food safety criteria for L. monocytogenes in RTE foods: – In RTE food for infants and special medical purposes L. monocytogenes must not be present in 25 g, – L. monocytogenes must not be present in levels above 100 cfu/g during the shelf life of other RTE products.2012-05-27 National Public Health Institute – National Institute of Hygiene 22
  23. 23. RTE foods that NOT SUPPORT the growth of the bacterium • L. monocytogenes must not be present in levels above 100 cfu/g during the shelf life.2012-05-27 National Public Health Institute – National Institute of Hygiene 23
  24. 24. RTE foods that SUPPORT the growth of the bacterium• L. monocytogenes must not be present in 25 g at the time of leaving the production plant;• however, if the producer can demonstrate, that the product will not exceed the limit of 100 cfu/g throughout shelf life this criterion does not apply.2012-05-27 National Public Health Institute – National Institute of Hygiene 24
  25. 25. • Formed as result of increased number of listeriosis in 1980-90’s in USA after consumption of deli meats and other processed products.• Zero tolerance - no detectable level of L. monocytogenes in RTE food products permitted.• One of long-term initiatives was to conduct a risk assessment for L. monocytogenes together with FDA.2012-05-27 National Public Health Institute – National Institute of Hygiene 25
  26. 26. • The goal was to predict the relative public health impact of foodborne Listeria monocytogenes from selected 23 food categories.• RTE foods to asses were chosen, if had a history of either Listeria monocytogenes contamination or were implicated epidemiologically.• This risk assessment have been used as base for FAO WHO reccomendations.2012-05-27 National Public Health Institute – National Institute of Hygiene 26
  27. 27. Decreased Risk per Annum Pâté and Meat Spreads Deli Meats Unpasteurized Fluid Milk No food categories Frankfurters (not reheated) Smoked Seafood High Fat and Other Dairy Products Pasteurized Fluid Milk Cooked RTE Crustaceans No food categoriesDecreased Risk per Serving Soft Unripened Cheese Deli-type Salads Dry/Semi-dry Fermented Sausages Frankfurters (reheated) Preserved Fish No food categories Fresh Soft Cheese Fruits Semi-soft Raw Seafood Cheese Soft Ripened Cheese Vegetables Cultured Milk Products Hard Cheese No food categories No food categories Ice Cream and Other Frozen Dairy Products Processed Cheese Very high risk High risk Moderate risk Low risk Very low risk
  28. 28. • Includes two food categories: – Deli Meats, – Frankfurters, Not Reheated.• They have high predicted relative risk rankings on both a per serving and per annum basis, because: – Have relatively high rates of contamination. – Support the relative rapid growth of Listeria monocytogenes under refrigerated storage. – Are stored for extended periods. – Are consumed extensively. – These products have also been directly linked to outbreaks of listeriosis.• This risk designation is one that is consistent with the need for immediate attention in relation to the national goal for reducing the incidence of foodborne listeriosis. Likely activities include the development of new control strategies and/or consumer education programs suitable for these products. 2012-05-27 National Public Health Institute – National Institute of Hygiene 28
  29. 29. • Includes four food categories: – Cultured Milk Products, – Hard Cheese, – Ice Cream and Other Frozen Dairy Products, – Processed Cheese.• These products all have in common the characteristics of being subjected to a bactericidal treatment, having very low contamination rates, and possessing an inherent characteristic that either inactivates Listeria monocytogenes (e.g., Cultured Milk Products, Hard Cheese) or prevents its growth (e.g., Ice Cream and Other Frozen Dairy Products, Processed Cheese).• This results in a very low predicted per serving relative risks. The predicted per annum relative risks are also low despite the fact that these products are among the more commonly consumed RTE products considered by the risk assessment.• The results of the risk assessment predict that unless there was a gross error in their manufacture, these products are highly unlikely to be a significant source of foodborne listeriosis.2012-05-27 National Public Health Institute – National Institute of Hygiene 29
  30. 30. • European Comission launched the survey on Listeria monocytogenes in selected categories of ready-to-eat food at retail in the EU.• RTE food categories under investigation: – Smoked and gravad fish, – Soft and semi-soft cheeses, – Heat-treated meat products.• Analyses methods: – L. monocytogenes detection and enumeration, – pH and aw measurement,2012-05-27 National Public Health Institute – National Institute of Hygiene 30
  31. 31. 2012-05-27 National Public Health Institute – National Institute of Hygiene 31
  32. 32. • Listeriosis is serious infectious foodborne disease.• Many factors affect on risk of listeriosis.• Food producers have not influence on many of them.• Initial quality of food - no Listeria at detectable level is the best method to increase the food safety.2012-05-27 National Public Health Institute – National Institute of Hygiene 32

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