Dietary exposures to mineral hydrocarbons from food-use applications in the United States.

Food-use applications of mineral hydrocarbons (MHC) derived from petroleum sources result in dietary exposure to these compounds by consumers. Food applications of MHC, including white mineral oils, paraffin waxes, microcrystalline waxes and petrolatum, include both direct-additive uses in which the MHC is intentionally applied to the food and indirect-additive uses in which the MHC become components of the food due to migration from food-contact surfaces. A key consideration in evaluating the safety of these uses of MHC is the level of exposure that results. We estimated exposures to MHC in the US from food applications based primarily on a food-consumption approach, in which MHC concentrations in foods were multiplied by the amount of these foods consumed. This was a conservative estimate, because it assumes that all foods that might contain MHC in fact do so at maximum possible concentrations. A "poundage approach", in which the amount of MHC used in food applications was divided by the US population to determine maximum potential per capita exposures, was used to validate the consumption-based estimates. Exposures to MHC from food-packaging applications were estimated using the FDA's food-factor approach, which takes into account the volume and kinds of food packaged with specific types of materials. A conservative estimate of mean exposure to all MHC types combined is 0.875 mg/kg BW/day. Half of this, 0.427 mg/kg BW/day, is white mineral oils used as pan-release lubricants in baking, for de-dusting of stored grain, in confectioneries, and in coatings for fruits and vegetables. Nearly all of the remainder, 0.404 mg/kg BW/day, is petrolatum, primarily from its use as trough grease in bakery applications. Exposure to paraffin and microcrystalline waxes combined is only 0.044 mg/kg BW/day.

Fortification contributed greatly to vitamin and mineral intakes in the United States, 1989-1991.

The objective of this work was to quantify the contribution of fortification (defined here as adding nutrients beyond traditional enrichment standards) to dietary nutrient intakes in the United States. A list of fortified foods was developed that was relevant at the time of the analyses, and prefortification (naturally occurring) nutrients in the fortified foods were determined from industry-supplied data. Using dietary data from the 1989-1991 Continuing Survey of Food Intakes by Individuals (CSFII), intakes of nine nutrients were determined both as reported in the CSFII (i.e., postfortification) and also by using prefortification nutrient levels for the identified fortified foods. We report data for the total population age >/= 1 y based on respondents (n = 11,710) with 3 d of dietary data, as well as select age/gender subgroups. All data were weighted. Fortification substantially increased the intakes of all nutrients examined except calcium, in all age/gender groups but especially in children. In numerous cases, fortification was responsible for boosting median or 25th percentile intakes from below to above the RDA. The breakfast cereal category was responsible for nearly all the intake of nutrients from fortified foods, except vitamin C for which juice-type beverages made as great or a greater contribution. These data from 1989 to 1991 serve as a useful baseline with which to compare contributions of fortification as the practice expands. The large contribution of fortification even in 1989-1991 suggests that continued monitoring of fortification practices, using methods such as those presented here, is important.

Evaluation of the budget method for screening food additive intakes.

The Budget Method, originally developed for determining food additive use limits, has been proposed as a tool for screening food additive intakes to establish monitoring priorities. Theoretical Maximum Daily Intake (TMDI) estimates derived using the Budget Method rely on assumptions regarding physiological requirements for energy and liquid and on the energy density of food rather than on food consumption survey data. This report summarizes work performed to determine the validity of Budget Method assumptions and to assess the potential for error in assigning monitoring priority based on Budget Method results. Budget Method assumptions regarding energy and liquid intake were compared with data from UK, German and US nationwide food consumption surveys. It was found that the Budget Method assumptions of energy intake and liquid intake are higher than mean intakes reported in surveys. The Budget Method assumption regarding energy density of foods also was found to be a slight overestimate. Budget Method TMDIs for case study additives were in each case larger than survey-based 95th percentile per capita additive intake estimates. Based on these results, the Budget Method appears to be a suitably conservative screen for establishing additive monitoring priorities based on potential lifetime average intakes.

International Interface Standard for Food Databases.

An International Interface Standard for Food Databases is under development to help overcome the technical and semantic barriers to the use of food-related databases. The Interface Standard is a system for efficient storage of all relevant descriptive information about foods. The schema for the Standard consists of ten components--food/food product identification, food names, LANGUAL factors, other food descriptors, other descriptive coding systems, ingredients/recipes, standards, substances, organizations, and data sources. The Interface allows for retrievals of data associated with specific foods from databases by using queries based on any of a wide variety of descriptive terms. The schema of the Interface has been completed; the remaining work is to build the computer software to provide access to, and use of, the schema.

Use of food-intake surveys to estimate exposures to nonnutrients.

Several steps must be taken in estimating intake of (or exposure to) dietary nonnutrients such as additives, drug residues, pesticide residues, toxicants, and natural nontoxicant chemicals. The first step involves consideration of relevant characteristics of the nonnutrient, including biological activity, physical/geographical sources, distribution in the food supply, typical concentrations, and the desirability of intake. After reviewing chemical characteristics, appropriate food-consumption data to use in the exposure assessment must be identified and obtained. Survey methodology must be reviewed carefully to determine compatibility with the characteristics of the chemical. The best available nonnutrient concentration data must be identified and obtained and the exposure models must be chosen. Available models include average exposure, simple distribution, joint distribution, and commodity contribution.

Nutritional availability to rats of selenium in tuna, beef kidney, and wheat.

Weanling male rats were fed a selenium (Se)-deficient 40% Torula yeast diet for 4 weeks and were then continued on depletion for another 4 weeks or were repleted with 0.1, 0.2, or 0.3 ppm Se as sodium selenite or 0.2 ppm Se as tuna, beef kidney, or high-Se wheat. There were no significant differences in young red blood cell Se, unfractionated red blood cell Se, or liver Se levels in groups fed diets containing 0.2 ppm Se. Glutathione peroxidase (GSH-Px) activity in young red blood cells was lower in the three groups fed food Se than in the group fed selenite (0.2 ppm Se). Young red blood cell GSH-Px was significantly lower in rats fed tuna than in rats fed wheat. Unfractionated red blood cell GSH-Px was lower in rats fed tuna than in rats fed selenite, but did not differ significantly among groups fed food Se sources. Liver GSH-Px was significantly lower in rats fed tuna than in rats fed kidney, wheat, or selenite. Availability of Se was only 54-58% as great from tuna as from selenite for induction of GSH-Px in liver and in red blood cell populations. Therefore, low availability of Se from fish may have to be considered when assessing Se status of human beings from dietary intake.