Interagency Retail Listeria monocytogenes Risk Assessment .ppt

1、,Interagency Retail Listeria monocytogenes Risk Assessment Data Sources, Data Review, and Data Gaps,- Rgis POUILLOT CFSAN/FDA/HHS June 23, 2009,2,Outline,What are the Data Needs? Request for data and information: Federal Register noticesWhy? Cross-Contamination Data needs, Data sources, Data review,

2、 Data GapBacterial Growth Data needs, Data sources, Data review, Data Gap Cleaning and Sanitizing Data needs, Data sources, Data review, Data Gap,3,Federal Register Notices,4,Request for data (1/4),Characteristics of RTE food markets in the United States, including: Volumes of cheeses, deli-type sal

3、ads and deli meats sliced/prepared by manufacturers and the volumes sliced/prepared in retail facilitiesCharacteristics of deli departments in groceries, including the proportion of separated seafood/meat/dairy deli departments in groceries.,5,Request for data (2/4),Listeria monocytogenes (Lm) level

4、s and/or frequencies in products arriving at retail facilities and sold by retail facilities.Factors that influence the growth of Listeria monocytogenes in cheeses, deli meats, and deli-type salads, including: Growth rates of Listeria monocytogenes, Chemical characteristics of cheeses, deli meats, a

5、nd deli-type salads, Proportions of deli meats treated with growth inhibitors, the inhibitors used, the level of growth inhibitors, and their efficiency; Data on the temperatures to which cheeses, deli meats, and deli-type salads are exposed at retail.,6,Request for data (3/4),Environmental contamin

6、ation data, including: Data and information on the prevalence and levels of Lm in the retail environment; Data on the growth of Lm on non-food surfaces including environmental biofilm growth.Factors that influence the environmental contamination and the cross-contamination of food by Listeria monocy

7、togenes in retail facilities, including: Data and information on the potential transfer of Lm to food from the retail environment, e.g., experimental studies on the transfer to food from drains, slicers, food contact surfaces, and non-food contact surfaces; and Data and information on food handlers

8、activities, e.g., observations of food handlers practices and monitoring of specific food safety actions in retail facilities.,7,Request for data (4/4),Identity and effectiveness of control measures or interventions intended to reduce levels and frequency of Lm in the retail environment, including:

9、Environmental sanitation procedures including the sanitizers and protocols used, frequency of application, and efficiency; and Worker sanitation procedures including frequencies, protocols, and efficiency.Any other data related to the occurrence, growth, and control of Listeria monocytogenes in reta

10、il facilitiesVery wide areas,8,Major Data needs,Factors that Impacts the Final ContaminationInitial Contamination in ProductsCross-ContaminationBacterial Growth Cleaning and Sanitizing,9,Cross-Contamination (transfer of Listeria monocytogenes),10,Needed Data? One Cross-Contamination.,Initial contami

11、nation of A Transfer coefficient from A to B Proportion of bacteria that shifts from A to B Published literature,A,B,A,B,A,B,11,Transfer Coefficient Studies,0.36 100%,0.001 12%,0.003 100%,0.001 45%,0.021 72%,Example: Chen et al., 2001108 Enterobacter aerogenes skinless chicken breast meat A particip

12、ant cut the meat handle a faucet wash hands cut a lettuce Bacterial count on the hands, the faucet, the lettuce,12,Literature Review,Currently 900 transfer coefficients from 20 references Issue: huge variability Source, Recipient, Contact, Bacteria, e.g. transfer coefficients from meat stainless ste

13、el surface,Transfer coefficient,13,A Special Case: the Slicer,Transfer of L. monocytogenes from an inoculated slicer blade (108 CFU/blade) to uninoculated turkey, salami and bologna. (Vorst et al., 2006),Log10 CFU/slice,14,Multiple Cross-Contaminations,15,Additional Data Needed,Frequency / Probabili

14、ty of Contact between Objects,Slice Chub,Contact Hand - NFCS,Replace Chub,How frequent is a contact Hand - Non Food Contact Surface (NFCS)?,?,After a contact Hand - NFCS, what is the probability that the food worker changes his gloves? Before changing his gloves: What is the probability that he also

15、 washes his hands? ,16,Pilot Observational Study,In 9 retail facilities: observation of food worker behaviorsFirst results: very standard practices | food worker Once scaled on a realistic value, the sensitivity of the output to this parameter may be tested Objectives for a more complete study,“Coll

16、aboration and/or supported by JIFSAN, UM, FDA, FMI”,17,Cross-Contamination: Remaining Data Gap,Probability and level of transfer from / to the NicheData: AFDO study, Cornells data, but Questions remain, e.g.: Drains origin or indicators of contamination? Cart wheels origin or indicators of contamina

17、tion? Quantification?,18,Growth,time,log x,19,Listeria monocytogenes Growth,The result of bacterial growth may be an increase of a few bacteria to 10,000,000 bacteria per gram of product in few daysBacterial growth is a function of: Time Environment Temperature, pH, water activity, Bacteria Characte

18、ristics StrainCharacteristics of Listeria monocytogenes Growth Growth may occur at Low temperature: even between 29F - 40F (but at a low rate) (Relatively) low and high pH: from 4.5 to 9.6 Note: an increasing proportion of products with antimicrobial growth factors,20,Predictive Microbiology Model,U

19、se of mathematical models to predict the growth of bacteria over time under certain conditionsHuge improvements in the models in the last 20 years Interactions between parameters, Low concentrations, Lag phase, Varying environment, Growth - no Growth interface,21,Sources of Growth Data,Growth Rates

20、specifically acquired in the products Published Literature + Response to FR noticeCharacteristics of the products pH, water activity, antimicrobial growth factors Published Literature - Response to FR notice Storage Temperature at retail Cold room, Display cabinet Food Code (baseline) Ecosure 2008 s

21、tudy NAFSS studyStorage Duration at retail Food Code (baseline),22,Cleaning and sanitizing procedures,23,Needed data? One Cleaning.,Initial contamination of A Reduction in the number of bacteria during the cleaning / disinfection Published Literature,24,Log reduction: numerous studies,*ND=Not done,E

22、xample: Best et al., 1990,25,Data Sources,Product used Food Code (baseline) Literature review Observational study Response to FR noticeFrequency of cleaning operations (from “wipe out” to “complete cleaning”) Food Code (baseline) Literature review Observational study Response to FR noticeProtocol (e

23、.g. Duration) Food Code (baseline) Literature review Observational study Response to FR notice,26,From the Retail to the Risk,27,From the Retail to the Risk,Dose Response Model (probability of illness for a given dose),Probability of Illness,Contamination when sold,Contamination when eaten,Home Stor

24、age: bacterial growth Cross Contamination: not considered,28,Transport and Home Storage,Listeria monocytogenes Growth Predictive Microbiology ModelsTransport Ecosure 2008Home Storage Temperature: RTI 2007 and Ecosure 2008 studiesTime: RTI 2007 study,29,Conclusions,Some data are available but not all

25、 the needed dataTwo dockets opened for comments and data until September 29th www.regulations.gov Docket No. FDA-2008-N0658 Docket No. FSIS-2009-0012Some data gap will hardly be filled Probability / level of transfer Niche ProductLimitations of the model,30,Project supported in part by an appointment to the Research Participation Program at the CFSAN administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the U.S. FDA.,Thanks for your attention,