A New Model to Assess Incidental Ingestion Exposures to Residential Countertop Cleaning Products

Abstract

MAB2-PD-04 Introduction: The Antimicrobials Division of the U.S. Environmental Protection Agency's Office of Pesticide Programs proposed a model to assess potential incidental ingestion exposures resulting from antimicrobial pesticide products used on residential countertops. The components of the Environmental Agency (EPA) model (which was modified from an FDA model to estimate dietary intake from sanitizing rinses regulated as indirect food additives) are an assumed product residue on countertops (1 mg/cm2), food contacting a countertop area (2000 cm2/day per person), and complete transfer of residues to food. Because the EPA model lacks a rigorous basis, the American Chemistry Council Biocides Panel initiated a program to develop an appropriate screening-level exposure model. Methods: A Generic Food Consumption Model has been developed in which foods were categorized based on physical form and likelihood of residential countertop contact (eg, liquid, solid, purees, pieces, and powders). Assumed residues on countertops (mg/cm2) are converted to estimated residues in food (mg/kg) with a “translation factor” for each food category derived from the contact area, weight of a single piece/serving and default residue transfer efficiency for a representative food. Incidental ingestion exposure is calculated as the product of the estimated residue and the quantity consumed of each food category. Initially, countertop residues are not reduced for potable water rinses even though such rinses are required for food contact surface uses, which increases the conservatism of the model. Results: The Generic Food Consumption Model relies on concepts of food consumption and preparation patterns, which represents a true paradigm shift from the EPA approach. The model takes advantage of data and assumptions that are not chemical-specific and that are therefore applicable to a broad range of situations. The model estimates an incidental ingestion exposure for the general population that is reduced more than 90% compared with the very conservative EPA model. Conclusions: The Generic Food Consumption Model results in a refined, yet still conservative, estimate of incidental ingestion exposure that may result when food contacts antimicrobial product residues on countertops. In the future, development of chemical-specific data for antimicrobial chemicals/families would allow further refinement of incidental ingestion exposure estimates. Additional research could improve characterization of residues on countertops and consumer behavior regarding food preparation practices.