Chemical Testing for Indirect Food Additives in Paper Products
Paper products are used every day for packaging foods in a variety of applications. Paper plates, cups, cartons, wrappers, and boxes come in contact with food during storage, preparation, and service activities. For example, when you purchase a Chicken-Pot-Pie from the grocery store frozen section, paper containers are used to store the food, prepare the food in the microwave, and serve the food. All of these activities have the potential that materials present in the paper product could be transferred to the food.
Because of this potential, paper products are tested for:
• Food and Drug Administration (FDA) Regulations
• Manufacturing Quality Control for Consumer Product Health and Safety Program
• End-User or Customer Specifications
FDA Regulations: In order to meet FDA regulations for a paper product used for food contact, the company certifies that only FDA approved substances are used in the manufacture of the product. The list of FDA approved substances is complex and is found in 21 CFR Part 176 (Indirect Food Additives: Paper and Paperboard Components). In addition, specific regulatory approved testing procedures are required to demonstrate compliance. The main chemical screening method is an empirical FDA extraction test (21 CFR 176.170, Paragraph c), which specifies solvent, time, temperature, and contact area to simulate different food contact conditions. The solvent choice (water, heptane, 8% ethanol, or 50% ethanol) is determined by the type of food. Contact time varies from 15 minutes to 48 hours and temperature criteria vary from 70 to 250o F, dependent upon the use of the paper product.
There is a menu of nineteen different FDA extraction conditions to choose from. The extract shall not exceed 0.5 milligram per square inch of food-contact surfaces. The maximum criteria can be calculated on a parts-per-million (ppm) basis for comparative purposes. For a typical paper plate (basis weight 100 pounds per 1000 square feet), the FDA extract maximum calculates to 1,920 ppm. The FDA extraction method does not address maximum criteria for specific individual chemical compounds.
Manufacturing Quality Control: Companies test for specific chemical contaminants in their products as part of their overall consumer product health and safety program. For example, the Recycled Paperboard Technical Association (RPTA) developed a testing protocol for approximately 170 chemical contaminants in September 2001. Sampling frequency, analytical methods, and data reporting is specified in the RPTA protocol. Samples of paperboard are annually tested for volatile organics, semivolatile organics, polychlorinated biphenyls, organo-chlorine pesticides, polychlorinated dioxins/furans, and heavy metals. Test results are compared to maximum “allowable concentrations” (AC) for each specific chemical contaminant. AC levels are also dependent upon the coating type on the paperboard (polymer, clay, or none) and food type (aqueous, fatty, or all). The maximum allowable concentration can vary significantly. For example, the AC for 2,3,7,8-tetrachlorodibenzodioxin is 0.000002 ppm and the allowable concentration for 1,2-dichlorobenzene is 222 ppm. AC levels are calculated using conservative assumptions associated with toxicity mechanisms and exposure pathways.
Customer Specifications: End users of paper products also have protocols to monitor for specific potential chemical contaminants. The end-user may include the converting plant customer or the food packaging plant customer or others. The paperboard manufacturer and end user agree to sample frequency, analytical procedures, and contract maximum concentrations of chemical contaminants. These contract maximum concentrations are typically lower than a regulatory maximum concentration.
For example, let’s get back to the Chicken-Pot-Pie purchased from the grocery store. When packaging was first developed for microwave applications, an analytical method was required to simulate the microwave conditions and monitor for volatile organic compounds that may arise from heating the packaging material. These methods were developed in conjunction with the FDA and maximum allowable concentration guidelines were determined for 10 potential volatile organic contaminants (acrylonitrile, benzene, chloroform, carbon tetrachloride, ethyl acrylate, epichlorohydrin, 1,4-dioxane, 1,2- dichloroethane, dichloromethane, and trichloroethylene). In order to incorporate an additional margin of safety, the food packaging customer’s contract requirements were significantly lower than these regulatory levels (by an order of magnitude) for two of the volatile organics that were considered more critical than the other eight volatile organics. Customers can be very specific in their testing requirements.
Summary: Paper products that come in contact with food are manufactured with FDA approved materials, are tested to demonstrate regulatory compliance, and monitored for specific chemicals to meet end-user health and safety program needs. Analytical methods to provide test results come from regulatory procedures and internally developed procedures. CAS has been providing these testing services for more than ten years to the pulp, paper, and packaging industries. CAS provides a team approach from initial product evaluation through on-going monitoring for product quality documentation