Carcinogenicity risk assessment for constituents of food additives

6 Carcinogenicity risk assessment for constituents of food additives 

As discussed above, the Delaney clause applies to substances proposed for use as food additives, but does not apply to individual constituents of a food additive. Examples of constituents would include residual monomers or catalysts. The constituents policy, subjected to judicial review in Scott v. FDA, 728 F. 2d 322 (6th cir. 1984), states that FDA may consider the potential risks of constituent exposure under the general safety standards set forth in FFDCA. The notification process places the responsibility upon the notifier for addressing the carcinogenic risk of constituent exposure from a proposed use of a food additive. FDA recommends that notifiers include in their food contact notification a safety narrative that addresses the safety of each carcinogenic constituent at any exposure (in addition to the recommendations listed in Table 7.1). This narrative should include an estimate of the potential human cancer risk from the constituent due to the proposed use of the food contact material (FDA, 2002). 

For most food contact materials, a worst-case estimate of the upper bound lifetime cancer risk (LCR) is sufficient to demonstrate safety and allows for the most efficient and complete review process possible. Although such an approach may be overly conservative, this less precise approach allows for a reasonable prioritization of resources without reducing the certainty of safety. The recommended approach for establishing this worst-case upper bound LCR from exposure to a constituent in a food additive is described in more detail below. 

the highest appropriate unit cancer risk (UCR) is determined from the tumor data from the most sensitive species, strain, sex, and study (FDA, 2002). Tumor incidences not considered treatment related are omitted from analysis statistical significance is an important tool in evaluating the relationship of treatment to tumor induction. If only one dose was tested and only one type of tumor was induced, then the UCR is defined as the slope of the straight line of tumor incidence versus dose. 

UCR = (number of tumors in test group - number of tumors in controls)/(test dose - control dose) 

---