Risk assessment as the scientific basis for policy decisions: possibilities and limitations

Transcription

1 Risk assessment as the scientific basis for policy decisions: possibilities and limitations O. Cerf 2011-Nov-25 AFSCA-FAVV 1

2 In plain language Be a health problem (nature and severity) associated with the consumption of a food In the food Its causative biological, chemical of physical agent: the hazard In the population Its probability/frequency of occurrence with this severity: the risk 2011-Nov-25 AFSCA-FAVV 2

3 In plain language The application of Good Hygiene Practices + HACCP principles based on Hazard Analysis results in the present situation with respect to the morbidity and mortality from foodborne infectious diseases According to countries, this situation is called: Appropriate Level of Protection (ALOP) Acceptable Level of Risk 2011-Nov-25 AFSCA-FAVV 3

4 Yet GHP and HACCP principles are applied link by link along the food chain Misinterpretation of the HACCP system is frequent An oversight in the EU Hygiene Package Machinery intended for use with foodstuffs in Directive 2006/42 on Machinery Hygiene Process Microbiological Criteria Indicators becoming hazards when Conc. Labeling of storage t and 2011-Nov-25 AFSCA-FAVV 4

5 What should be done When the level of sanitary protection degrades, when the risk is no longer acceptable? When the public opinion asks for a better level of protection? More Regulation Inspections Penalties More or more stringent hazard control measures 2011-Nov-25 AFSCA-FAVV 5

6 Present situation: focused on hazards Roughly satisfactory But: Empirical Each link of the food chain tends still to act independently The effect on the risk of hazard control measures is unknown in general 2011-Nov-25 AFSCA-FAVV 6

7 Doing better? Towards a risk focused approach

8 The World is changing Since the 1st January 1995, in international trade, States have to do a scientific risk assessment to justify their decisions as regards their sanitary protection (SPS Agreement) Today, the global approach to food safety should therefore be focused on the acceptable level of risk, or appropriate level of protection (ALOP) 2011-Nov-25 AFSCA-FAVV 8

9 Risk Analysis Risk Assessment In plain language Scientific evaluation by independent experts Risk Management Political evaluation and decisions by the competent authority on how to achieve the ALOP/ALR Laws, regulations, inspections, penalties, etc. Risk Communication Interactive, between all interested parties, on risks, risk factors, risk perceptions and opinions Hazard control = operators 2011-Nov-25 AFSCA-FAVV 9

10 Qualitative risk assessment

11 Scientific qualitative assessment Combination of factors Probability of occurrence, score from 1 to 3 Consequences, score from 1 to 3 Combination = multiplication Codex Alimentarius Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance (CAC/GL ) 2011-Nov-25 AFSCA-FAVV 11

12 Examples Campylobacteriosis High probability of occurrence, mild symptoms 3 x 1 = 3 Listeriosis Low probability of occurrence, high lethality of symptomatic listeriosis 1 x 3 = 3 What can the risk manager decide? 2011-Nov-25 AFSCA-FAVV 12

13 A suggested approach (Animal Health Expert Committee AFSSA 2008) Assessment of the probability of occurrence 0 Nil (N) 1 Nearly Nil (NN) 2 Minute (M) 3 Extremely Low (EL) 4 Very Low (VL) 5 Low (L) 6 Not Very High (NVH) 7 Quite High (QH) 8 High (H) 9 Very High (VH) / / /500 1/100 1/25 1/5 1 ratio 10 6, Nov-25 AFSCA-FAVV 13

14 Assessment of the consequences Health and economic consequences for ONE farm Potential of the disease spreading National and/or international economic repercussions Cumulative consequences for animal health in the country 0 to 3 0 to 3 0 to 3 0 to Nov-25 AFSCA-FAVV 14

15 Consequences Occurrence AFSSA à à à à à à à à à 81 Weight of the consequences on the risk 2011-Nov-25 AFSCA-FAVV 15

16 Yet It is postulated that risk zero may exist To the linear scale of scores corresponds a non linear, heterogeneous scale of probability of occurrence The scale of consequences is further extended when estimating the risk Collective training of the experts is needed With respect to food safety, a probability of 10-6 cannot be called Nearly Nil 2011-Nov-25 AFSCA-FAVV 16

17 Another qualitative approach (ANSES Microbiology Expert Group) For evaluating technological processes Does the process reduce the consumer exposure to the hazard(s)? Recent ANSES examples Submit bovine carcasses to UV rays? Decontaminate poultry carcasses with acids? Decontaminate flour with peracetic acid? Submit prepared dishes to high pressure processing? 2011-Nov-25 AFSCA-FAVV 17

18 Quantitative risk assessment

19 Quantitative risk assessment (1) 1. Exposure assessment Assess the dose (ingested amount) of the hazard to which the consumer is exposed Dose = concentration x volume or mass of serving Know the hazard concentration/frequency Know the serving volume and consumption frequency 2011-Nov-25 AFSCA-FAVV 19

20 Quantitative risk assessment (2) 2. Consequence assessment: the dose-response relationship Assess the probability of the studied health effect E as a function of the dose D: Probability (E D) D x (probability of E when D=1) D 50 dose causing effect E in 50% of exposures D 10, D 1,, D 0,0001, etc. For each effect of a same hazard For each vulnerable subpopulation 2011-Nov-25 AFSCA-FAVV 20

21 Proba. of the effect Probabilité de la réponse Quantitative risk assessment (3) 3. Risk estimation Assess the probability of occurrence Dose (log 10[cellules Log10(Dose) ingérées]) Per serving, per individual, for all servings of a given foodstuff, for all foodstuffs 2011-Nov-25 AFSCA-FAVV 21

22 Calculations are needed From simple ( deterministic, e.g. RIVM swift QMRAtool, ACFSE Risk Ranger, FARE Microbial) to highly complex ( probabilistic ), as a function of: The question The process The availability of data The time allowed Tools Monte Carlo simulation Bayesian inference 2011-Nov-25 AFSCA-FAVV 22

23 Publications ( ) 206 risk assessment, 50 dose-response papers, in title, cited by ISI Web of Knowledge SM 14 Pathogen Commodity Combination Risk Assessments by JEMRA - Joint FAO/WHO expert meetings on microbiological risk assessment ex.html 40 Risk Assessment Models JIFSAN -Joint Institute for Food Safety and Applied Nutrition (University of Maryland and USDA) ( Nov-25 AFSCA-FAVV 23

24 Hence The risk managers are provided with a lot of quantitative assessments of the risk of illness in the consumer population Are these useful to the food business operators and the risk managers? 2011-Nov-25 AFSCA-FAVV 24

25 What does the food business operator?

26 ALOP, Acceptable Level of Risk Abstract concepts for most food business operators An operationalization is needed FSO = food safety objective, maximum concentration and/or frequency at the time of consumption PO = performance objective, maximum concentration and/or frequency at a step earlier in the process 2011-Nov-25 AFSCA-FAVV 26

27 PC Effect of a control measure on a hazard concentration or frequency Harvest Objective : maximum hazard frequency and/or concentration Transport Réception Step 1 PO Microbiological criterion PC Step 2 Hazard control measures achieving process and/or product criteria PC Step 3 Step 4 Step 5 Packaging Transport Purchase Storage PO PO Microbiological criterion Microbiological criterion Preparation PC Cooking Consumption FSO ALOP/ALR 2011-Nov-25 AFSCA-FAVV 27

28 FSO We eat doses, not concentrations or frequencies A limit that should never be exceeded? Never say never Accept a percentage in excess? Which percentage: 5%, 1%, 0.1%? Is that prudent? 2011-Nov-25 AFSCA-FAVV 28

29 FSO Two foods in which the distributions of concentrations have the same percentage FSO 1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 Normal(1; 0,431) 0,05 0,04 0,03 0,02 0,01 0 Normal(-7; 3,864) X <= 2,000 99,0% X <= 2,000 99,0% -0,5 0 0,5 1 1,5 2 2,5 This food will cause more cases 2011-Nov-25 AFSCA-FAVV 29

30 What does the risk manager?

31 AFSSA (2008)- Microbiological contamination of powdered formulae for infants and the elderly Question What is the effectiveness of sampling for Enterobacteriaceae, Enterobacter sakazakii and Salmonella? 2011-Nov-25 AFSCA-FAVV 31

32 The competent authority could easily set explicit performance objectives for manufacturers of dried powdered formulae Most of the people heard said that they would like performance objectives to be supplied by the competent authority. This is also what the European Food Safety Authority recommended in AFSSA strongly encourages this approach, which would bring about a change in official control methods, focusing more on the verification that performance objectives are met. What the risk manager did? 2011-Nov-25 AFSCA-FAVV 32

33 Listeria monocytogenes in milk and milk products 1. Question to the Codex Alimentarius Committee on Food Hygiene (CCFH) at the end of the XX th Century «Is the risk of severe listeriosis linked to ripened soft cheeses made of raw milk acceptable?» 2011-Nov-25 AFSCA-FAVV 33

34 Dose-response relation of severe listeriosis (JEMRA 2004) 2011-Nov-25 AFSCA-FAVV 34

35 2. Listeriosis linked to ripened soft cheeses made of raw milk in France Brie cheese, no recontamination and no temperature abuse. Sanaa et al. Risk Analysis 24: (2004) The probability of one or more severe listeriosis cases per year is less than 10-3 Raw milk cheeses included in the Codex Alimentarius Code of hygienic practice for milk and milk products (CCFH 2004) 2011-Nov-25 AFSCA-FAVV 35

36 3. Number of listeriosis cases per year in the US associated with consumption of raw milk DP: farm bulk tanks, FS: farm stores, R: retail stores Latorre et al. Journal of Food Protection (2011) 5 years per century What the risk manager will do? 2011-Nov-25 AFSCA-FAVV 36

37 CCFH (2007) - Guidelines on the application of general principles of food hygiene to the control of Listeria monocytogenes in foods Question «Would it be possible to establish a microbiological limit other than absence in 25g in the microbiological criterion for foodstuffs in which L. monocytogenes growth can occur?» 2011-Nov-25 AFSCA-FAVV 37

38 Alternative approach The competent authorities may choose to establish and implement other validated limits for the L. monocytogenes concentration at the point of consumption or at other points that provide an acceptable level of consumer protection for foods in which L. monocytogenes will not grow as well as foods in which L. monocytogenes growth can occur. Thus, the 100 cfu/g limit in EU Regulation 2073/2005 is legitimated a posteriori by the Codex Alimentarius 2011-Nov-25 AFSCA-FAVV 38

39 AFSSA (2007) - Quantitative risk assessment for Escherichia coli O157:H7 in frozen beef burgers consumed at home in France by children under the age of 16 Question raised after an outbreak in France, end Nov-25 AFSCA-FAVV 39

40 Aged 0-5 D cfu Aged 6-10 D cfu Hemolytic uremic syndrome (HUS) Delignette-Muller, Cornu & AFSSA STEC Study Group International Journal of Food Microbiology (2008) 2011-Nov-25 AFSCA-FAVV 40

41 As regards frozen minced steaks, cooked according to common practice in home kitchens: The equation Risk = Concentration/100 can be used to estimate the average individual risk of HUS of children under 10 years of age, as a function of the concentration in raw minced meat What the risk manager did? 2011-Nov-25 AFSCA-FAVV 41

42 ANSES (2010) Opinion on microbiological contamination in the slaughterhouse Question «What are the hazards linked to evisceration accidents?» Assessment of the risk of contamination of carcasses by E. coli O157:H Nov-25 AFSCA-FAVV 42

43 In case of evisceration accidents, even minor, the meat should not be used for making vulnerable products such as minced meat What the risk manager did? 2011-Nov-25 AFSCA-FAVV 43

44 ANSES (2011) Quantitative assessment of risks associated with EHEC [ ] according to different consumption modes of minced meat Question «What is the effectiveness of sampling plans?» 2011-Nov-25 AFSCA-FAVV 44

45 Number or samples allowing the detection of STEC with 95% probability. n= number of steaks in the lot; N=total number CFUs in the lot; b=heterogeneity (clustering) factor of CFU distribution among the lot; m=weight of samples (g) Distribution of bacterial cells: heterogeneous homogeneous It is still not appropriate to establish a safety microbiological criterion for pathogenic STEC. Yet, these pathogens should be sought for own checks and the application of the general principles of the Hygiene Package. What the risk manager did? 2011-Nov-25 AFSCA-FAVV 45

46 Conclusion

47 Qualitative approaches Simple, quick Can be used in emergency situations Easy to understand and apply Can be overly simplistic Scoring with numbers can give the illusion of objectivity 2011-Nov-25 AFSCA-FAVV 47

48 Quantitative approaches More objectivity Forces to look closely Allows to optimize the interventions Needed when experiments can not be done, or when the risk is low Deterministic: can be overly simplistic Probabilistic: can be lengthy, costly seldom applicable in emergency situations can be difficult to understand and implement 2011-Nov-25 AFSCA-FAVV 48

49 Management focusing on hazards Easy Traditional inspection Empirical Each link of the food chain (farm, processing, distribution, table) is considered independently from the other links No quantitative relation established between hazard control measures and their consequences for public health 2011-Nov-25 AFSCA-FAVV 49

50 Management focusing on risks More scientific and systematic Focused on what is acceptable for public health Enables to consider the food chain in its entirety from the last link (the table) back to the first link (the farm) Enable process optimization Can be complex and difficult to understand Should lead to revise inspection techniques 2011-Nov-25 AFSCA-FAVV 50

51 Future Coexistence of qualitative and quantitative risk assessments, hazard and risk focused approaches According to situations According to available resources Yet, the risk focused approach will be used more and more 2011-Nov-25 AFSCA-FAVV 51

52 EU Food Law Regulation 178/2002 Article 6 In order to achieve the general objective of a high level of protection of human health and life, food law shall be based on risk analysis except where this is not appropriate to the circumstances or the nature of the measure Nov-25 AFSCA-FAVV 52

53 Thank you for your attention