listeria monocytogenes in food as public safety risk
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European Symposium on Food Safety 21-23 May 2012. Listeria monocytogenes in food as public safety risk. Grzegorz Madajczak, Ph.D . DVM [email protected]. The goal of this presentation :. Present, that Listeria monocytogenes it is not only the food quality / safety criterion, - PowerPoint PPT PresentationTRANSCRIPT
National Public Health Institute – National Institute of Hygiene
Listeria monocytogenes in food as public safety risk
Grzegorz Madajczak, Ph.D. [email protected]
EuropeanSymposium on
Food Safety21-23 May 2012
2014-09-30 2National Public Health Institute – National Institute of Hygiene
The goal of this presentation:Present, that Listeria monocytogenes it is not only
the food quality / safety criterion,but first of all public health risk.
2014-09-30 3National Public Health Institute – National Institute of Hygiene
Listeria monocytogenes• 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/
2014-09-30 4National Public Health Institute – National Institute of Hygiene
Listeria monocytogenes• 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
2014-09-30 5National Public Health Institute – National Institute of Hygiene
Listeriosis• 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).
2014-09-30 6National Public Health Institute – National Institute of Hygiene
Age and gender distributionof listeriosis
Data Source: ECDC TESSY
<1 1-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+0
200
400
600
800
1000
1200
FemaleMale
High number ofpregnancy associated cases
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Transmission of L. monocytogenes
Reservoir Source VehicleTransplacentar
infections
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L. monocytogenes in food procesing and retail
• 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.
“From farm to fork”
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Invasive listeriosis• Notificable disease.• Varied clinical forms are described:– Sepsis,– CNS infections,– Endocarditis,– Localised infections,
– Pregnancy associated infections
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Gastrointestinal listeriosis• Usually self-limiting febrile gastrointestinal disease
presenting with unspecific symptoms like:– Nausea,– Vomiting,– Diarrhea.
• Observed as sporadic cases and food-poisoning outbreaks.
2014-09-30 11National Public Health Institute – National Institute of Hygiene
Sporadic Listeria Gastroenteritis ?• Study conducted by Walter
F. Schlech III in 2002 in Canada.
• Material: stool spec. from 7775 diarrhea cases.
• Only 18 cases were caused by L. monocytogenes.
• L. monocytogenes could cause the sporadic gastroeteritis, but it is not importanant pathogen in such cases.
1813 2
1 4
137
140L. monocytogenesL. innocuaL. welshimeriL. grayiother ListeriaSalmonella sp.Campylobacter sp.
Schlech et al., CID 41 (2005), 778-784
2014-09-30 12National Public Health Institute – National Institute of Hygiene
Outbreaks of listeriosisFood-borne outbreak: „an incidence, observed under given circumstances, of two or more human cases of the same disease and/or infection, or a situation in which the observed number of human cases exceeds the expected number and where the cases are linked, or are probably linked, to the same food source”.(Directive 2003/99/EC)
Food vehicle: food (or foodstuff) that is contaminated by a causative agent.(EFSA, Manual for reporting of food-borne outbreaks […])
2014-09-30 13National Public Health Institute – National Institute of Hygiene
Outbreaks of listeriosis
Listeria monocytogenes is absolute foodborne pathogen, caused both: gastrointestinal and invasive listeriosis.
All listeriosis outbreaks should be classified as foodborne or at least waterborne.
2014-09-30 14National Public Health Institute – National Institute of Hygiene
Outbreaks of listeriosisCountry Year Food vehicle Affected
France 1999-2000 Pork tongue in jelly 26 casesUSA (multistate) 2008-2009 Mexican-style cheese made
from pasteurized milk 8 pregnant women
Czech Rep. 2006 Local cheese 75 casesCanada, Quebec 2008 Pasteurized milk cheese 14 pregnant women, 2 babies born to
asymptomatic carriersAustria, Germany, Czech Rep.
2009 Acid curd cheese “Quargel” 14 cases, 4 deaths
USA, Louisiana 2010 Hog head cheese 14 cases of invasive listeriosis
USA (multistate) 2011 Cantaloupe (Rockmelon) 84 people, 15 deads
• In 2012 year 37 alerts were notified in RASFF• In 2011 year 106 alerts were notified in RASFF
2014-09-30 15National Public Health Institute – National Institute of Hygiene
Pregnancy associated listeriosis• 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
Congenital listeriossis
Preterm birth
Stillbirth
Miscarriage
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Congentital listeriosis
Early-onset Late-onset
Associated with prematurity and acquired throw utero.
Caused by bacteria acquired from vaginal tract of asymptomatic mothers
Clinical symptoms occurs just after birth (mean-time is 1.5 day)
Occurs about 2 weeks post partum.
Sepsis Meningitis
• Depending on time of clinical symptoms manifestation, two types of infection are recognized
2014-09-30 17National Public Health Institute – National Institute of Hygiene
Severity of listeriosis• 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 deaths
Also psychological aspects
2014-09-30 18National Public Health Institute – National Institute of Hygiene
Listeriosis in Europe2%
4%
58%
1%
16%
14%
2%
4%
Number of RASFF alerts in 2010 year
bivalve molluscs and products thereof
crustaceans and products thereof
fish and fish products
gastropods
meat and meat products (other than poultry)
milk and milk products
poultry meat and poultry meat products
prepared dishes and snacks
2014-09-30 19National Public Health Institute – National Institute of Hygiene
Listeriosis in Europe
• The EU/EEA rate of confirmed human cases of Listeria infection has been relatively stable in the last four years.
Data Source: ECDC TESSY
2006 2007 2008 2009 2010130013501400145015001550160016501700
00.050.10.150.20.250.30.350.4
1654
1425
1581 1597 1637
0.350.3
0.34 0.36 0.37
No of cases Notification rate
• Listeriosis had the highest impact among the elderly (65+) with the highest confirmed case rates and high mortality.
2014-09-30 20National Public Health Institute – National Institute of Hygiene
Listeriosis in Europe
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 MT0
50
100
150
200
250
300
350
400390
312
176
12995
72 71 63 62 5940 35 29 22 20 11 10 10 7 6 5 5 5 4 1 1 1
Listeriosis cases in 2010 by country
Data Source: ECDC TESSY
2014-09-30 21National Public Health Institute – National Institute of Hygiene
Listeriosis in Poland
2005 2006 2007 2008 2009 2010 20110
20
40
60
0
0.05
0.1
0.15
0.2
22 2843 33 33
62 640.058 0.058
0.110.09 0.09
0.17 0.17
Cases Morbidity per 100 000
2005 2006 2007 2008 2009 2010 20110
2
4
6
8
10
0
0.5
1
1.5
2
2.5
31
5
0
6 680.84
0.27
1.29 1.44 1.45
1.94
Neonatal cases Morbidity per 100 000 of births
Listeriosis cases
Neonatal listeriosis
Data Source: Infectious diseases and poisonings in Polandhttp://www.pzh.gov.pl/oldpage/epimeld
2014-09-30 22National Public Health Institute – National Institute of Hygiene
Listeria monocytogenes – food safety criterions
• 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.
2014-09-30 23National Public Health Institute – National Institute of Hygiene
• L. monocytogenes must not be present in levels above 100 cfu/g during the shelf life.
RTE foods that NOT SUPPORT the growth of the bacterium
Listeria monocytogenes – food safety criterions
2014-09-30 24National Public Health Institute – National Institute of Hygiene
Listeria monocytogenes – food safety criterions
• 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.
RTE foods that SUPPORT the growth of the bacterium
2014-09-30 25National Public Health Institute – National Institute of Hygiene
USA FSIS L. monocytogenes“zero tolerance” politic in RTE
• 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.
2014-09-30 26National Public Health Institute – National Institute of Hygiene
Risk assessment to public health from foodborne L. monocytogenes
• 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.
Cultured Milk ProductsHard Cheese
Ice Cream and Other Frozen Dairy Products
Processed Cheese
Preserved FishRaw Seafood
No food categories
High Fat and Other Dairy ProductsPasteurized Fluid MilkSoft Unripened Cheese
Pâté and Meat SpreadsUnpasteurized Fluid MilkSmoked Seafood
No food categories
Deli-type SaladsDry/Semi-dry Fermented Sausages
Frankfurters (reheated)Fresh Soft Cheese Fruits Semi-soft
Cheese Soft Ripened Cheese Vegetables
No food categories
Cooked RTE Crustaceans No food categories
No food categoriesDeli MeatsFrankfurters (not reheated)
Dec
reas
ed R
isk
per S
ervi
ng
Decreased Risk per Annum
Moderate riskHigh risk Low riskVery high risk Very low risk
Risk assessment - results
2014-09-30 28National Public Health Institute – National Institute of Hygiene
Foods of very high risk• 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.
2014-09-30 29National Public Health Institute – National Institute of Hygiene
Very low risk food products• 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.
2014-09-30 30National Public Health Institute – National Institute of Hygiene
EU initiative for L. monocytogenes reduction in RTE foods
• 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,
2014-09-30 31National Public Health Institute – National Institute of Hygiene
Reduction of risk to public health from foodborne L. monocytogenes
2014-09-30 32National Public Health Institute – National Institute of Hygiene
Summary• 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.
2014-09-30 33National Public Health Institute – National Institute of Hygiene
•References: •www.slideshare.com