3. curation of food related toxcast chemicals database ... · pesticides for animal feed use no...

Curation of food related ToxCastchemicals database using chemicals database using exposure groupings to identify

t lcurrent relevance

Lori Fix, PhD, DABTAgnes Karmaus, PhDTom Trautman, PhD, DABT

28 July 2016

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Disclosure of interest

• This work is supported by the ILSI North America T h i l C itt F d Ch i l S f tTechnical Committee on Food Chemical Safety.

• Lori Fix, Ph.D., DABT is an employee of Unilever Company an ILSI North America Member company and Company, an ILSI North America Member company, and an ILSI North America Member Scientist

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THE AGE OF BIG DATA IN TOXICOLOGY

• Rapid evolution of high-throughput approaches for • Hazard screening

• Tox21• ToxCast• ToxCast• AOP refs

• Exposure estimates• ExpoCastp• CPCat (Chemical/Product Categories Database)• CPCPdb (Consumer Product Chemical Profiles database)• AEP refs

HIGH-THROUGHPUT SCREENING PROGRAMS

• Large chemical inventories• ToxCast with over 3,000 chemicals

• Evaluated across over 1 000 targeted assay endpoints Evaluated across over 1,000 targeted assay endpoints • With concentration-response

• Tox21 includes roughly 9,000 chemicals• 50 i it • 50 in vitro assays• in 15-point concentration-response

• Provides unprecendented quantities of data

HTP CHEMICAL INVENTORIES

• Compiled from a broad range of sources (publically available) including • Industrial products

A h l d• Agrochemical products

• Consumer products

• Food additives

• Donated pharmaceuticals

• Potential “green” alternative chemicals

ANNOTATION OF USE AND EXPOSURE SCENARIOS

• Consumer Product Chemical Profiles database (CPCPdb) • 1,797 chemicals • Mapped to 8921 consumer productsMapped to 8921 consumer products• In 353 “use categories”

• Chemical/Product Categories Database (CPCat)• Compiled information from a dozen sources • 43,596 chemicals • Associated with 833 controlled vocabulary usage terms

COMBINING DATABASES TO INFORM

• In combination, these large database sources can help to inform• in vitro chemical bioactivity leading to adverse outcomes

• Identify the uses to understand exposure routes for chemicals of interest

FOOD RELEVANT CHEMICALS IN TOXCAST

• A subset of ToxCast chemicals were examined in Karmaus et al. 2016• Food related or relevant

• US l t• US-relevant

• By mining publicly available databases

• 1,530 chemicals were identified

• Manual curation was needed

• No longer used in US foods

• Use restricted resulting in limited exposure

MANUAL CURATION NEEDED – AN EXAMPLE

• Nordihydroguaiaretic acid (NDGA)• Approved for food use in 1943 as an antioxidant and preservative of fats and oil• Withdrawn for food use in 1968 due to rat nephropathy toxicityp p y y• NDGA is listed in the FDA EAFUS database• Tested as a ToxCast chemical

• Elicited concentration-dependent effects in a relatively large number of ToxCast in vitro assay endpoints

• As there is no current exposure concern from food NDGA it should be removed from consideration as a food-use chemicalbe removed from consideration as a food use chemical

MANUAL CURATION NEEDED FOR MANUAL CURATION NEEDED FOR TOXCAST FOOD RELEVANT CHEMICALS

• This study presents a comprehensive manual review

• 1,530 food-relevant ToxCast chemical list

• Curation to determine current use or regulatory status

• Incorporate exposure related insights regarding food-use

Note: This is unpublished work and will be submitted to a peer-reviewed journal

CURATION RESULTS

• Refined US food relevant ToxCast chemical inventory from 1530 to 1,211

• Exposure Categories based on likelihood of US exposure highest to lowest1. Direct food additives

2 Indirect food additives2. Indirect food additives

3. Indirect pesticide residues

4. Non-food

• Furthermore, extensive manually curated comments have been added providing context on use and regulatory status for the entire 1,530 chemical inventory


EXPOSURE CATEGORIES ASSIGNMENTS

1. Direct food additives

• Confirming current direct food or color additives • Listings in Code of Federal Regulations (CFR; 21CFR, Parts 1-190)

• FDA notified GRAS self-determinations

• GRAS listings of the Flavor and Extract Manufacturer’s Association (FEMA; G S s gs o e avo a d ac Ma u ac u e s ssoc a o ( M ; www.femaflavor.org/gras)

• Naturally occurring chemicals in foods e.g. citric acid or linoleic acid

**Note: Not all GRAS inventory remain direct additives after manual curation



2. Indirect food additives

• Confirming current indirect food additives (21CFR, Parts 1-190)

• Packaging components

• Manufacturing lubricants

• Equipment sanitizersEquipment sanitizers

• Processing aids



3. Pesticide residues

• Currently registered for food use in the US 40CFR180

• Tolerances

• Import tolerances

• Inerts



4. Non-food uses

• Currently not registered for use in food

• Drugs

• Cosmetics and fragrances

• Pesticides without current tolerances

• Industrial chemicals


EXPOSURE CATEGORIES ASSIGNMENTSEXPOSURE CATEGORIES ASSIGNMENTS

Multiple Category Assignments for a single chemicalMultiple Category Assignments for a single chemical

• 90 chemicals were assigned in more than one category

• 70 of the 406 categorized pesticide chemicals have other uses warranting classification in more than one categorymore than one category

For example

• Chemicals registered by the US EPA as inert ingredients in various pesticides formulations that also had reg lated ses as also had regulated uses as

• Flavors

• Emulsifiers

• Plasticizers


EXPOSURE CATEGORIES ASSIGNMENTSRESOURCESRESOURCES

• Publically available sources were used for evaluation• EPA Aggregated Computational Toxicology Resource (ACToR)• EPA R i t ti Eli ibilit D i i D t (RED ) • EPA Registration Eligibility Decision Documents (REDs) • Burdock’s Encyclopedia of Food and Color Additives• Cornell University’s Legal Information Institute• EC’s Fl@voring Substances Database• Flavor and Extract Manufacturer’s Association GRAS determination listings• Title 21 Code of Federal Regulations • Title 40 Code of Federal Regulations• FDA Glossary of Pesticide Chemicals, 2005y ,• FDA’s Everything Added to Food in the US (EAFUS)• PAN Pesticides Database• There are numerous chemical supply house websites, occupational safety websites (safety

in handling) patents Alan Wood Sittig’s Handbook etc that could give clues to function in handling), patents, Alan Wood, Sittig s Handbook, etc. that could give clues to function of a chemical


EXPOSURE CATEGORIZATION

Database Identified Food Relevant Chemicals1530

N F dNon-Food319No Exposure

Food Relevant Chemicals with Potential Exposure

1211

Direct Additives Indirect Additives Pesticides43% 26% 31%

556 339 406

Multiple categories 90

NON-FOOD USES – NO FOOD EXPOSURE

CriteriaNumber of Chemicals

Pesticides cancelled in US, no import tolerances 87

Pesticides216

Pesticides foreign use only, no import tolerances 98Pesticides for non- agricultural or veterinary use 25Pesticides for crack and crevice use only 3Pesticides for animal feed use no food tolerance 3Pesticides for animal feed use, no food tolerance 3

Variousnon‐food

Drugs 19Cosmetics 6Fragrances 6

68 Industrial chemicals 35

Medical devices 2

Cancelled Banned or cancelled chemicals 11

Misc. Miscellaneous non-food related use or lacking information 24


EXAMPLE OF CURATION

• Sulfamic acid

• Sourced from the FDA SCOGS GRAS database

• Although it is assumed to be a direct additive due to its GRAS listing

• The use is actually for a packaging application – an indirect additive


IMPACT OF CURATION

Karmaus et al. 2016Pre-manual curation Curation

Direct Additives616

Direct Additives Curated550

Move to Indirect AdditivesMove to Indirect Additives54

Move to Pesticides3939

Move to Non-food Uses28


IMPACT OF CURATION


Indirect Additives371

Indirect Additives Curated281

Move to Direct AdditivesMove to Direct Additives6

Move to Pesticides4646



IMPACT OF CURATION


Pesticides543

Curation

Pesticides Curated321

M D AddMove to Direct Additives0

Move to Indirect Additives44



CYTOTOXICITY CENTER ANALYSIS

• Evaluation and comparison of the curated food relevant chemicals • Evaluation and comparison of the curated food-relevant chemicals, similar to Karamus et al. 2016

• In this approach the mean cytotoxicity across a battery of 14 • In this approach the mean cytotoxicity across a battery of 14 cytotoxicity assays (Judson 2016) is calculated for each chemical and plotted as a distribution per use categoryp o ed as a d s bu o pe use ca ego y

• A minimum of 3 positive cytotoxicity assay responses are needed to meet a “positive” response assignmentmeet a positive response assignment


CYTOTOXICITY CENTER ANALYSIS RESULTS

Category Total Chemical Number with a % with a Curated Categories

Category Total Chemicals

Chemical Number with a Cytotoxicity Center

% with a Cytotoxicity Center

Direct Additives 556 54 10*

Indirect Additives 339 82 24

Pesticides 406 166 41

*Note that direct food additives have the lowest number of chemicals with a cytotoxicity center


CONCLUSIONS

• To appropriately interpret and analyze large datasets there is a To appropriately interpret and analyze large datasets there is a need for curation and contextualization

• Historical data is often included in database inventoriesHistorical data is often included in database inventories

• Which may not reflect current regulatory or use status

• May lead to misinterpretation without curation• May lead to misinterpretation without curation

CONCLUSIONS

• Incorporating exposure considerations into the classification of chemicals

• In combination with the ToxCast in vitro assay data

• Provides deeper insight for prioritizing food-use chemicals warranting further toxicological testingg g