Presentation on theme: "1 Quantitative Risk Assessment of Chemicals in Food and Beverages Felicia Wu, PhD John A. Hannah Distinguished Professor Department of Food Science & Human."— Presentation transcript:
1 Quantitative Risk Assessment of Chemicals in Food and Beverages Felicia Wu, PhD John A. Hannah Distinguished Professor Department of Food Science & Human Nutrition Department of Agricultural, Food, & Resource Economics Michigan State University
2 Why quantitative risk assessment? The public hears about risks in foods/beverages all the time, some of which may truly cause fear: –At work –In the news –From your family and friends We’ll be better off if we can assess: –Whether this “agent” (GMOs, lead, arsenic) is really hazardous to human health (Hazard Identification) –How much of it causes a harmful effect, vs. how much is safe (Dose- Response Assessment) –Whether we or others we care about are exposed to the agent in amounts that could cause harm (Exposure Assessment) –Whether this risk is, after all, worth our concern (Risk Characterization)
3 What is risk assessment? “The process of quantifying the probability and magnitude of a harmful effect to individuals or populations from certain agents or activities.” Practically speaking, what does this mean? –There are 2 main components to assessing risk: The magnitude of harm The probability of occurrence –If you don’t have both of these, you don’t have a risk –If you do have both of these, you can quantify the risk for policy decision-making purposes
5 Hazard Identification Determine whether agent of interest causes disease, based on weight of evidence from studies. Major sources of information –Human (epidemiological) studies: cohort and case-control studies most informative* –Animal (toxicological) studies: basis of most dose-response assessments Supplemental sources of information –Cell culture assays –Structure-activity relationships *Limited for many foodborne and waterborne toxins “Tox21”: reduce or eliminate animal tests through bioinformatics & high-throughout screening
6 Guidelines for Judging Causality (So: is it a hazard after all?) When we finally evaluate all of the scientific studies for our agent of concern in the Hazard ID process, we need some set of criteria to determine if the sum total of the studies establishing an association between exposure and a health effect reach the level of establishing causation.
7 Bradford-Hill criteria in summary 1.Exposure to agent precedes disease 2.“Strong” relationship between agent & disease 3.Dose-response relationship exists (higher doses more disease risk) 4.Findings can be replicated 5.Biological plausibility 6.Consideration of other explanations 7.Cessation of exposure leads to reduced disease 8.Specificity (1 agent 1 disease) 9.Findings are generalizable
8 Dose Response Assessment Purpose The objective of Dose Response Assessment is to determine the relationship between dose of a toxic agent and the occurrence of health effects. The information is often provided by the same animal and human studies used for Hazard Identification. Dose Response Assessment addresses non-carcinogenic and carcinogenic effects separately and differently.
Dose-response assessment Non-carcinogenic effects NOEL (no observed effect level) or benchmark dose found in animal study Extrapolate to safe dose for humans: divide NOEL/BMDL by uncertainty factors –Usually 100 (10 for inter- species variability * 10 for intra-species variability) This is reference dose (RfD) or tolerable daily intake (TDI). Carcinogenic effects For genotoxic carcinogens, “no safe level” Linearize dose-response curve & drive through (0, 0) –Slope of line is slope factor, or cancer potency factor –For every unit increase in daily dose of carcinogen, cancer risk increases by the cancer potency factor (e.g., aflatoxin) 9
Exposure assessment (dietary toxins) Traditional ADD = (C ave * IR ave ) / BW where ADD = Average daily dose, C ave = concentration (average) of toxin per unit food or drink, IR ave = intake rate (average) of the relevant food or drink (usually determined by dietary surveys), BW = body weight ADD units: mg/kg bw/day Human biomarkers of exposure Substance measured in human biospecimen (e.g., urine, blood, hair) –Indicates that person was exposed to particular toxin –May be used to estimate his/her dietary intake of toxin –Can indicate long-term or short- term exposure to toxin –Must be validated (i.e., shown to increase or decrease with actual increasing or decreasing dietary intakes) 10
Risk Characterization Does the agent pose a significant human health risk? How much? Non-carcinogenic risk: compare average daily dose (ADD) of toxin to its reference dose (RfD) or tolerable daily intake (TDI). Hazard Quotient = ADD / RfD (HQ >>1 implies risk to health) Carcinogenic risk: multiply lifetime average daily dose (LADD) of toxin by its slope factor or “cancer potency factor” (from the dose-response curve). Risk = LADD * Slope Factor Risk = a unitless proportion of the population developing cancer from a particular substance
12 Aflatoxin & Global Health Effects Aflatoxin produced by Aspergillus flavus, A. parasiticus –Maize, peanuts, tree nuts, cottonseed, spices, copra –Exposure highest in warm regions where maize & nuts are dietary staples (Africa, Asia) Human health effects –Hepatocellular carcinoma (HCC, liver cancer) Synergizes with chronic hepatitis B virus (HBV) infection: much higher risk than either exposure alone –Childhood stunting –Acute aflatoxicosis –Immune system modulation What do risk assessments tell us about global impact of aflatoxin ?
Quantitative cancer risk assessment: How many HCC cases worldwide are caused by aflatoxin? (Liu & Wu 2010) Dose-response assessment –Slope of curve = cancer “potency” Aflatoxin HCC: 0.01 cases / 100,000 per yr per ng/kg bw/day Aflatoxin+HBV HCC: 0.30 cases / 100,000 per yr per ng/kg bw/day (JECFA 1998) Exposure assessment Find, for each nation: –Daily consumption of maize / nuts –Aflatoxin levels in maize / nuts –HBV prevalence –Population size –Captured 5.96 billion people 13
14 Risk characterization: Simplified model Global population cancer risk = Σ (all nations) ([Population HBV+ /100,000 * Potency HBV+ * Average aflatoxin intake] + [Population HBV- /100,000 * Potency HBV- * Average aflatoxin intake]) –Potency HBV+ = 0.30 cases per 100,000/yr per ng/kg bw/day –Potency HBV- = 0.01 cases per 100,000/yr per ng/kg bw/day Data Sources: HBV prevalence: WHO, multiple peer-reviewed papers Aflatoxin exposure & food consumption: FAOSTAT, multiple peer- reviewed papers
Results: 25,200-155,000 global aflatoxin- induced liver cancer cases/yr 15 ~5-30% of all HCC cases Where does aflatoxin-induced liver cancer occur? Liu Y, Wu F. (2010). Global Burden of Aflatoxin-Induced Hepatocellular Carcinoma: A Risk Assessment. Environ Health Perspect 118:818-824.
““The science has to drive all the regulatory decision making,” says Shelly Burgess, an FDA spokesperson.”
Influence diagram linking arsenic to human disease
Arsenic and new rice. Cotton pesticides still contaminate fields now used for food crops Environmental Health Perspectives Volume 115, Number 6, June 2007 Arsenic accumulates in rice & grains Rice Not So Nice for Babies? Environmental Pollution volume 152, 2008
Inorganic and organo-arsenic Inorganic As(III) Inorganic As(V) Organic MMA (V) Organic DMA(V) Organic arsenobetaine Organic arsenocholine Organic arsenothiols Organic arsenosugars Organic arsenolipids Low level concentration in fin fish, crabs, shrimps and mollusks 19 Seaweeds, marine mollusks
Quantitative cancer risk assessment Global estimate for cancer burden = [Individual population arsenic exposure * Cancer slope factor] (i) Dose – response assessment: Slope of curve = cancer potency Bladder and Lung Cancer Morales et al. (2000) Skin cancer EPA IRIS Conversion of water arsenic level (µg/L) to human dose (µg/day) Cancer typeSlope factor (increased cancer risk per µg iAs/kg bw/day) MalesFemales Bladder0.00001270.0000198 Lung0.00001370.0000194 Skin0.000025 20
Mean adjusted total arsenic content of foods used in the EFSA (2009) dietary exposure estimates. Food group Total arsenic lower bound mean level (mg/kg) Total arsenic upper bound mean level (mg/kg) All cereal & cereal products0.06710.0848 Sugar products and chocolate0.01350.0320 Fats (vegetable and animal)0.00630.0245 All vegetables, nuts, pulses0.01210.0212 Fruits0.00510.0155 Juices, soft drinks and bottled water0.0030 0.0068 Coffee, tea, cocoa0.00340.0051 Alcoholic beverages0.00550.0151 All meat and meat products, offal0.00440.0138 All fish and seafood1.61361.6159 Eggs0.00420.0117 Milk and milk-based products0.00440.0139 Miscellaneous/special dietary products 0.3993 0.4187 Source: Table 13, FAO/WHO JECFA Monographs 8, 2011. 21
Reported conversion factors from total arsenic to inorganic arsenic Data SourceFoodMean % inorganic Arsenic EFSA (2009)Fish Standard ratio 0.015 or 0.03 mg/kg Seafood products Standard ratio 0.05 or 0.10 mg/kg Rice50–60 (30–90 reported in literature) Cereal products and vegetables30–100 Tea29–88 Edible algae60 Yost, Schoof & Aucoin (1998) Milk and dairy products 26 Meat100 Poultry41 Source: Table15, FAO/WHO JECFA Monographs 8, 2011 22
Global burden of cancers caused by foodborne arsenic CancerMaleFemaleTotal (global) Total estimated incidence of cancers (global) % of global cases due to foodborne arsenic Bladder 4527 to 46,420 4,602 to 72,756 9,129 to 119,176 382,660 a 2.39 to 31.15 Lung 4,913 to 50,373 6,931 to 71,069 11,844 to 121,442 1,608,055 a 0.74 to 7.55 Skin8,941 to 91,679 17,882 to 183,358 2 to 3 million b 0.72 to 7.34 a Data source: “GLOBOCAN 2008 v2.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 10 [Internet]” b Data source: http://www.who.int/uv/faq/skincancer/en/index1.htmlhttp://www.who.int/uv/faq/skincancer/en/index1.html These numbers represent the expected number, globally, of additional cases of bladder, lung, and skin cancer per year; due to inorganic arsenic through food in different diets worldwide. 23
Risk management Your risk characterization tells you that 1 in a million Americans will develop lung cancer as a result of being exposed to Chemical X. How will you manage the risk, if at all?
Summary –Risk assessment consists of 4 steps: Hazard ID Dose-response assessment Exposure assessment Risk characterization –Can be applied to estimating burden of disease caused by food and beverage contaminants Aflatoxin, arsenic –Risk managers must decide how to use risk assessment data 25
The Business Case for Food Protection: Food Safety, Food Fraud, and Food Defense John Spink, PhD Director, Food Fraud Initiative Michigan State University * www.foodfraud.msu.eduwww.foodfraud.msu.edu -- Twitter @FoodFraud and #FoodFraud
27 The FOOD RISK MATRIX The Types of Food Protection Risks Action IntentionalUnintentional Harm: Public Health, Economic, or Terror Food Defense Food Safety Motivation Gain: Economic Food Fraud (1) Food Quality The Cause leading to the Effect of Adulteration Source: Adapted from: Spink (2006), The Counterfeit Food and Beverage Threat, Association of Food and Drug Officials (AFDO), Annual Meeting 2007; Spink, J. & Moyer, DC (2011) Defining the Public Health Threat of Food Fraud, Journal of Food Science, November 2011
28 Enterprise Risk Management Continuum from Operational Risk Operational Risk Enterprise Risk Metal Shavings Source: Spink, SRA Conference, 2009, 5 th Global Forum on Pharmaceutical Anti-Counterfeiting 2010 Tactical Quantitative ROI Strategic Qualitative Vulnerability ShopliftingCounterfeiting
29 ERM and CRO Enterprise Risk Management (ERM) and a Chief Risk Officer (CRO) are becoming more common. –CFO/CRO expanding focus to all-hazards within their structure… Understand and speak the language of risk Use a Risk Matrix and Risk Summing Focus on strategic nature of risk: pro and con –Develop a Food Protection risk assessment consistant with other corporate templates –Consider Food Protection with the context of all other enterprise-wide risks
30 Calibrating the Risk Assessment to the Corporate Risk Appetitive Risk Analysis –Risk Assessment Hazard Identification –Risk Management –Risk Communication Risk Threshold Risk Mitigation
32 Business Case to Respond to HONEY SMUGGLING What: Honey is smuggled from high tariff countries then transshipped through other countries and illegally relabeled. Why Worry: Recalls or mislabeling due to incorrect country of origin. –Cost of a recall? Vulnerability? How Caught: Banned antibiotics, adulterated by dilution Question: Before considering all costs, how could you address it? –Review incidents in the marketplace, review similarities –Review suppliers and procurement process –Test for country of origin? Antibiotics and dilution –Communicate process to suppliers –Review program to test incoming goods, review market for new incidents, review testing protocol –Review costs and vulnerability vs. other enterprise- wide risks Action: Mitigate, Transfer, or Retain – always monitor
33 Laws Regulations Standards Certifications Foundation: HACCP, GMP, GAP, Six Sigma Business Laws: Sarbanes-Oxley, Park Doctrine (Strict Liability), Enterprise Risk Management Food Protection Laws-US: FDA Bioterrorism Act (Traceability), Food Safety Modernization Act –Science- and risk-based approach, written risk assessment Food Protection Laws: EP/EU Draft Resolution on Food Fraud (and others on Medicines), Codex Alimentarious – TBD –Harmonize terms and focus on prevention Certifications and Standards: GFSI and Third Party Standards, USP/ Food Chemicals Codex, ISO Standards, Accounting Practices Requirements for a Risk Assessment
34 Thank You John Spink, PhD SpinkJ@msu.edu www.foodfraud.msu.edu Twitter: @Food Fraud and #FoodFraud 517.381.4491