Threshold of estimated toxicity for regulation of indirect food additives

Application of the threshold of toxicological concern concept to pharmaceutical manufacturing operations

A scientific rationale is provided for estimating acceptable daily intake values (ADIs) for compounds with limited or no toxicity information to support pharmaceutical manufacturing operations. These ADIs are based on application of the "thresholds of toxicological concern" (TTC) principle, in which levels of human exposure are estimated that pose no appreciable risk to human health. The same concept has been used by the US Food and Drug Administration (FDA) to establish "thresholds of regulation" for indirect food additives and adopted by the Joint FAO/WHO Expert Committee on Food Additives for flavoring substances. In practice, these values are used as a statement of safety and indicate when no actions need to be taken in a given exposure situation. Pharmaceutical manufacturing relies on ADIs for cleaning validation of process equipment and atypical extraneous matter investigations. To provide practical guidance for handling situations where relatively unstudied compounds with limited or no toxicity data are encountered, recommendations are provided on ADI values that correspond to three categories of compounds: (1) compounds that are likely to be carcinogenic, (2) compounds that are likely to be potent or highly toxic, and (3) compounds that are not likely to be potent, highly toxic or carcinogenic. Corresponding ADIs for these categories of materials are 1, 10, and 100 microg/day, respectively.

Guidance for the safety assessment of botanicals and botanical preparations for use in food and food supplements

There is a growing interest by both consumers and industry for the development of food products with 'functional' properties, or health benefits. These products may take the form of dietary supplements or of foods. The health benefits are given by particular ingredients, and in many cases these are derived from botanicals. The variety of plants providing these functions is large, ranging from staple food sources such as cereals, fruits and vegetables, to herbals as used in traditional medicine. The food or ingredient conferring health properties may consist of the plants themselves, extracts thereof, or more purified components. The scientific literature is abundant with articles not only on the beneficial properties, but also on possible adverse health effects of plants and their components. The present report discusses the data required to determine the safe use of these types of ingredients, and provides advice on the development of risk assessment strategies consistent with due diligence under existing food regulations. Product specifications, composition and characterisation of standardised and authentic materials, documented history of use and comparison to existing products (taking into account the effect of industrial processing), description of the intended use and consequent exposure are highlighted as key background information on which to base a risk evaluation. The extent of experimental investigation required, such as in vitro, animal, and/or human studies, depends on the adequacy of this information. A decision tree is presented as an aid to determine the extent of data requirements based on product comparison. The ultimate safety in use depends on the establishment of an adequate safety margin between expected exposure and identified potential hazards. Health hazards may arise from inherent toxicities or contaminants of the plant materials, including the mechanism of the intended beneficial effect. A lower safety margin may therefore be expected than for food ingredients or additives where no physiological effects are intended. In rare cases, post launch monitoring programmes may be envisaged to confirm expected exposures and adequacy of the safety margin. This guidance document was elaborated by an expert group of the Natural Toxin Task Force of the European Branch of the International Life Sciences Institute--ILSI Europe and discussed with a wider audience of scientists at a workshop held on 13-15 May 2002 in Marseille, France.

Risk assessment in regulatory policy making for human and veterinary public health

Risk assessment is the method of systematically identifying and assessing factors that influence the probability and consequences of a negative event occurring. One responsibility of veterinary medicine is to protect animal and human health. Food animal production uses antibiotics to enhance production. Regulators evaluate new production technology to ensure animal safety and safe, edible products and to make public policy decisions by assessing risks/benefits. The U.S. Food and Drug Administration, Center for Veterinary Medicine's (CVM's) first risk assessment addressed the potential human health impact of campylobacter effects associated with the use of fluoroquinolines in food-producing animals. CVM used the Monte Carlo method to estimate risk byprobability distributions that reflect the uncertainty and variability in the data used for the assessment. Enterococci faecium is a species more likely to be resistant to antibiotics of last resort. Effective control of multidrug-resistant enterococci will requirea better understanding of the transfer of E. faeciumfrom animals to humans and the interaction between E. faecium, the hospital environment, and humans; prudent antibiotic use; better contact isolation in hospitals; and better surveillance. CVM will model these factors in a second, more complex risk assessment designed to examine the indirect transfer of resistance from animals to humans. Use of risk assessments allows researchers, the industry, regulatory authorities, and educators to make better policy decisions regarding antimicrobial use in food animals and humans and the development of resistance. Today the question of whether the use of antimicrobials for growth enhancement infood animals should or should not be terminated for the benefit of human health remains unresolved.

Veterinary drugs no longer need testing for carcinogenicity in rodent bioassays

The putative carcinogenic risk to humans from ingestion of edible tissues containing traces of nongenotoxic veterinary drugs is so slight that the routine application of rodent cancer bioassays cannot be justified. This argument is based, first, on the pharmacological similarity of veterinary and human drugs: many of the latter that are carcinogenic to rodents have been deemed on mechanistic and/or potency grounds not to pose a cancer risk to humans. Second, the distribution of a veterinary drug through the target animal body before ingestion of a portion of edible tissue by humans days or weeks later means that the human dose from a residue is several orders of magnitude lower than the normal dose of human drugs. The dose of residue is also much lower than the exposure of humans to the most potent carcinogens.