The Metal Dietary Exposure Screening Tool (MDEST)

Transcription

1 The Metal Dietary Exposure Screening Tool (MDEST) Leila Barraj, Nga Tran, Carolyn Scrafford, Terry Troxell Exponent, Inc. JIFSAN, January 12, 2016

2 Metals in Foods Metals occur in the soil, water, and air Multiple sources for environmental metals Always been in the human diet Not unexpected to find metals in foods and food ingredients US Total Diet Survey (TDS) Code of Federal Regulations (CFR) Citations Food Chemicals Codex (FCC) Specifications Joint FAO/WHO Expert Committee on Food Additives (JECFA) Specifications 2

3 Need for Prioritization Metals ubiquitous in foods Improved analytical tools Metals are physiologically active Some Beneficial Toxicity possible at high doses Guidance Levels (e.g., tolerable daily intakes (TDI), reference doses (RfD)) are being lowered or removed altogether Industry faced with decisions on metals in foods and ingredients 3

4 Metal Dietary Screening Tool (MDEST) Provides information on metals exposures for use in decision making Apportions maximum acceptable dietary exposure levels into a background component and an MDEST component, that is the fraction of maximum of the acceptable exposure level after accounting for background exposure Quickly estimates metals exposures for food products based on: National Health and Nutrition Examination Survey (NHANES) consumption data Contaminant levels provided by the user Access the tool at ILSINAtool.org 4

5 MDEST Model Description Metal Dietary Exposure Screening Tool (MDEST) Screening tool for ingredients used in processing of food products Five metals: Arsenic, Cadmium, Chromium, Lead, Mercury Uses a Risk-Based Approach: Module 1- Hazard Characterization Establish default exposure limits based on existing exposure limits and existing dietary (background) exposure MDEST includes default values that can be over-ridden by user Module 2 Dietary Exposure Assessment Derive screening-level dietary exposure estimates based on (i) Concentration levels provided by the user and (ii) Hard wired consumption data Module 3 - Risk Characterization Compares the screening-level dietary exposure estimates to the exposure limits using two methods: (i) % of the exposure limit and (ii) Maximum number of servings per day that can be consumed and still result in an intake below the exposure limit 5

6 Model Construct for MDEST PTDI- Provisional Tolerable Daily Intake CFR- Code of Federal Regulations CSFII- Continuing Survey of Food Intakes by Individuals FITS- Feeding Infants and Toddlers Study NHANES- National Health and Nutrition Examination Survey FCID- Food Commodity Intake database RAC- Raw Agricultural Commodities TDS- Total Diet Study 6

7 Hazard Characterization: Default Values Used in MDEST 7

8 Arsenic The FDA (21 CFR ): a quality standard limit for inorganic arsenic in bottled water of 10 ppb Consumption of 2L of water per day containing 10 ppb inorganic arsenic results in a Tolerable Daily Intake (TDI) of 20 μg/day or approximately 0.3 μg/kg bw/day for a 60 kg individual Metals Exposure Limits Background Exposures MDEST Portion Inorganic Arsenic TDI: 0.3 µg/kg bw/day Food + drinking water: 95% of TDI (arbitrarily set) µg/kg bw/day (5% of TDI) 8

9 Cadmium The Joint FAO/WHO Expert Committee on Food Additives (JECFA) Provisional Tolerable Weekly Intake (PTWI) of 5.8 μg/kg bw/week (or a Provisional Tolerable Daily Intake (PTDI): 0.83 μg/kg bw/day) FDA: Maximum allowable limit of 5 μg/l in bottled water Metals Exposure Limits Background Exposures MDEST Portion Cadmium PTWI 5.8 µg/kg bw/week (PTDI: 0.83 µg/kg bw/day) (JECFA 2010) Food: µg/kg bw/day (Mean - 90 th percentile, TDS , US2+y) Drinking water: 0.17 µg/kg bw/day (Bottled water limit, FDA 2007) Food + drinking water= ~ µg/kg bw/day (Mean - 90 th percentile) 0.3 (= ) to 0.47 (= ) µg/kg bw/day 9

10 Chromium Chromium III (less toxic form): The European Food Safety Authority (EFSA): upper safe limit of 250 μg/day Chromium VI (more toxic form): US EPA: Oral Reference Dose (RfD) of 0.9 μg/kg bw/day Metals Exposure Limits Background Exposures MDEST Portion Chromium III Chromium VI 250 µg/day (Supplements, EFSA 2010; World Health Organization (WHO) 1996) RfD: 0.9 µg/kg bw/day (EPA, 2010) Food: 54 µg/day (Institute of Medicine (IOM), 1997) Drinking water: 7.2 µg/day (Total Cr, 90 th Percentile, ATSDR 2008) Food + drinking water: 61.2 ug/day Food + drinking water: µg/kg bw/day (95% of RfD, arbitrarily set) µg/day (= µg/day) µg/kg bw/day (5% of RfD) 10

11 Lead FDA: Provisional Total Tolerable Intake (PTTI) levels for various age groups Metals Exposure Limits Background Exposures MDEST Portion Lead PTTI: Children 0-6 yrs: 6 µg/day Children 7+ yrs: 15 µg/day Pregnant Lactating Females: 25 µg/day Adults: 75 µg/day (Carrington and Bolger, 1992) Food + drinking water: Vulnerable subpopulations (Children & females of childbearing ages): 50% of PTTI Other adults: 1/3 of PTTI Vulnerable populations: remaining 50% of PTTI: Children 0-6 yrs: 3 µg/day Children 7+ yrs: 7.5 µg/day Pregnant Lactating Females: 12.5 µg/day Adults: remaining 2/3 of the PTTI:50 µg/day 11

12 Mercury JECFA: Provisional Tolerable Weekly Intake (PTWI) of 4 μg/kg bw/week Metals Exposure Limits Background Exposures MDEST Portion Mercury (Total) PTWI 4 µg/kg bw/week or PTDI 0.57 µg/kg bw/day (JECFA, 2011) Food: µg/kg bw/day (Mean - 90 th percentile, TDS , US2+y) Drinking water: ~0.07 μg/kg bw/day, (Based on bottled water limit, FDA 2007) Food + drinking water= µg/kg bw/day 0.36 (= ) to 0.44 (= ) µg/kg bw/day 12

13 Dietary Exposure 13

14 Dietary Exposure Assessment: Consumption Data Option Food grouping method Number of Categories Data source Option 1 Broad 21CFR 45 categories NHANES Option 2 Refined CFR 320 expanded categories NHANES Option 3 Option 4 Option 5 FCID Raw Agricultural Commodities (RAC) FDA Total Diet Study (TDS) Feeding Infants and Toddlers Study (FITS) CFR- Code of Federal Regulations CSFII- Continuing Survey of Food Intakes by Individuals EFH- Exposure Factors Handbook FCID- Food Commodity Intake Database 353 RAC groups NHANES food groups (per capita only) Age 4-11M: 26 categories Age 12-24M: 34 categories (per serving only) CSFII FITS 2002 as summarized in EPA EFH (2011) FITS- Feeding Infants and Toddlers Study NHANES- National Health and Nutrition Examination Survey RAC- Raw Agricultural Commodities TDS- Total Diet Study 14

15 Dietary Exposure Assessment: Option 1: Broad CFR Categories CFR Broad Categories (-2) Baby, bottled water (-1) Baby food (0) Water (1) Baked goods and baking mixes (2) Beverages, alcoholic, cocktail mixes (3) Beverages and beverage bases, nonalcoholic (4) Breakfast cereals, RTE, instant, hot (5) Cheeses, natural, processed, spread, dip (6) Chewing gum (7) Coffee and tea, regular, instant etc CFR- Code of Federal Regulations 15

16 Dietary Exposure Assessment: Option 2: Refined CFR Categories Baked goods and baking mixes: CFR subcategories (1) (1) Baked goods and baking mixes - Bagel (1) (2) Baked goods and baking mixes - Biscuits, corn bread, muffins (1) (3) Baked goods and baking mixes - Bread stuffing (1) (4) Baked goods and baking mixes - Breads and rolls - rye, oat, other (1) (5) Baked goods and baking mixes - Breads and rolls - white (1) (6) Baked goods and baking mixes - Breads and rolls - whole/cracked wheat, multigrain (1) (7) Baked goods and baking mixes - Breakfast/cereal and granola bars (1) (8) Baked goods and baking mixes - Cake - rice (1) (9) Baked goods and baking mixes - Cake, cupcakes 80 g serving size (1) (10) Baked goods and baking mixes - Cookie dietetic (1) (11) Baked goods and baking mixes - Cookies and brownies (1) (12) Baked goods and baking mixes - Crackers etc CFR- Code of Federal Regulations 16

17 Dietary Exposure Assessment: Option 3: FCID RAC Categories RAC Categories in MDEST (1A) Alfalfa, seed (2A) Amaranth, leafy (3A) Apple, canned (3B) Apple, canned, babyfood (4A) Apple, fresh or n/s (4B) Apple, fresh or n/s, babyfood (5A) Apple, juice (5B) Apple, juice, babyfood (6A) Apricot, canned (6B) Apricot, canned, babyfood (7A) Apricot, fresh or n/s (8A) Apricot, frozen etc FCID- Food Commodity Intake Database RAC- Raw Agricultural Commodities 17

18 Dietary Exposure Assessment: Option 4: FDA TDS Categories TDS Food Categories in MDEST Milk, whole, fluid Milk, lowfat (2%), fluid Milk, chocolate, lowfat, fluid Milk, skim, fluid Milk shake, chocolate, fast-food Cheese, American, processed Cheese, cheddar, natural (sharp/mild) Beef, ground, regular, pan-cooked Beef roast, chuck, oven-roasted Ham, cured (not canned), baked Pork chop, pan-cooked w/ oil etc. TDS- Total Diet Study 18

19 Dietary Exposure Assessment: Option 5: FITS Categories FITS Food Categories (4-11m) 100% juice Baby food applesauce Baby food bananas Baby food desserts Baby food dinners Baby food green beans Baby food peaches Baby food pears Baby food squash Baby food sweet potatoes Baby foot carrots etc FITS Food Categories (12-24m) 100% juice Beef Bread Candy Canned fruit Cheese Chicken or turkey, plain Chicken nuggets Cookies Corn Crackers etc FITS- Feeding Infants and Toddlers Study 19

20 Dietary Exposure Assessment: Hard-Wired Data Options Age group For Each Food Category 1 (CFR Broad) 2 (CRF refined) 3 (FCID RAC) Five population groups: US 2+y, Infants 6m-2y, Children 2-6y, Children 7-12y, Females 14-45y 4 (TDS) Five population groups: Total US, Infants 6-11 months, Children 6 y, Children 10 y, Females y 5 (FITS) Six population groups: Infants 4-5m, 6-8m, 5-11m; Infants 12-14m, 15-18m, 19-24m Per capita mean consumption (g/day) Percent consumers Per capita mean consumption (g/day)* Per serving consumption (g/serving)* * When applicable consumption g/kg BW/day calculated using default BW per age group based on NHANES CFR- Code of Federal Regulations FCID- Food Commodity intake database FITS- Feeding Infants and Toddlers Study NHANES- National Health and Nutrition Examination Survey RAC- Raw Agricultural Commodities TDS- Total Diet Study 20

21 Dietary Exposure Assessment: Algorithms hard wired Mean estimates: Per capita: Summed across food categories Per user: Per capita mean / % consumers If more than one food/food group, % consumers estimate assumes complete overlap: Most conservative estimate of combined % consumers and per user intakes (smallest % consumers, hence largest per user mean) Complete overlap Partial overlap No overlap Food 2 Food // 1 Food 2 Food 1 Food 2 Food 1 21

22 Dietary Exposure Assessment: Algorithms hard wired Upper percentile estimates: Uses/expands FDA pseudo-upper percentile approach: 90 th percentile = 2 x mean (FDA) 95 th percentile = 4 x mean (FDA) 99 th percentile = 6 x mean (expanded from FDA) 22

23 Exposure Assessment User Input Concentration For Options 1, 2, 4, and 5: Default: Assumes concentration value is on finished product But user can specify if it applies to ingredient in finished product and provide corresponding % For Option 3 (FCID RAC): Default: Assumes concentration value applies to ingredient 23

24 Exposure Assessment User Input Concentration Arsenic exposure scenarios: Default: Assumes As concentration refers to ias But user can specify a conversion factor to transform concentration value from total As to ias 24

25 Risk Characterization: Two Approaches 25

26 Risk Characterization: Approach 1 Output Description User modifiable? Output 1: All options except Option 5 (FITS) - Compares estimated screening level exposure derived in Module 2 to the exposure limit established in Module 1 No FITS- Feeding Infants and Toddlers Study 26

27 Risk Characterization: Approach 2 Output Description User modifiable? Output 2: All options except Option 3 (FCID RAC data) and Option 4 (TDS food groups ) FCID- Food Commodity Intake Database FITS- Feeding Infants and Toddlers Study - Calculates the maximum number of servings that can be consumed without exceeding exposure limit established in Module 1. - Default serving size: RACC for Options 1&2, and FITS for Option 5 - If more than one food group: Approach 1: Assume exposure from each food separately Approach 2: Proportionately allocate exposure limit to all foods in assessment Users can replace RACC serving size with their own data RAC- Raw Agricultural Commodities RACC- Reference Amounts Customarily Consumed 27

28 Additional considerations for users of MDEST For contaminants such as cadmium and lead where more than 50% of PTDI remains available for use in the MDEST, further assessment should be made to ensure that not all of the exposure limit established in Module 1 is inappropriately assigned to a single or a few foods/ingredients with low intake. When exposure limits exist for certain food/ingredients, such as those established by FCC, Codex, FDA, such limits must be followed and the MDEST cannot be used to justify contaminant levels exceeding existing limits. Finally remember it is a SCREENING TOOL 28

29 Metal Dietary Exposure Screening Tool Access to ILSI North America MDEST, implementation guide, manuscript and case studies at ILSINAtool.org 29

30 Questions?