Food safety assessments
Safety assessments for food additives are expressed in terms of the acceptable daily intake (ADI) estimated on the basis of lifetime exposure. While it is clearly not possible to collect food consumption data over the lifetimes of individuals, it is important that the dietary data used for the purpose of estimating accept-able levels of intake over a lifetime reflect, as far as is possible, the habitual level of intake of the foods being assessed.
For the purpose of food safety assessments only the intake of “consumers” is of interest. It follows, there-fore, that the dietary data need to be adequate to obtain both an accurate estimate of the proportion of the population who are consumers and of the average habitual intake of consumers. Because the frequency of consumption varies between foods (some foods are eaten by most people on most days, but many other foods are eaten less frequently), the duration of the dietary recording period influences both the esti-mate of the proportion of consumers and the average intake of consumers. Intake data for 1 day will inevi-tably underestimate the true number of consumers for most foods and overestimate the average habitual intake of those consumers because not all foods are eaten every day. However, it appears that 75% or more of household menu items are normally consumed within a 14 day period and that a 14 day diary pro-vides a good estimate of the habitual intake of most foods by consumers.
Most studies of the food intake of individuals, however, do not last for 14 days because of the increased cost and nonresponse associated with such a long study period. For the purpose of food safety assessment an approach that combines a 3 day food intake record with a food frequency questionnaire has the potential to give estimates for the intake of con-sumers that are similar to those obtained from 14 day records.