US Food and Drug Administration's Total Diet Study: intake of nutritional and toxic elements, 1991-96

The Food and Drug Administration (FDA) has conducted the Total Diet Study (TDS) annually since 1961. The TDS is designed to monitor the US food supply for levels of toxic chemical contaminants (pesticide residues, industrial chemicals and toxic elements) and nutritional elements. Foods are generally collected four times a year, once from each of four regions of the country. The foods are prepared table-ready before being analysed. From the results of the TDS, dietary intakes of these analytes are estimated for selected age- sex groups in the US population. This paper reports on the dietary intake of 10 nutritional and four toxic elements based on measurements made in foods collected in the TDS between 1991 and late 1996. Average daily intakes were estimated for 14 age-sex groups in the US population, as well as the contribution of specific food groups to total intakes. For most nutritional elements, teenage boys and adult males had the highest daily intakes. Intakes by infants were below the intake references for seven of 10 nutritional elements, and young girls and women had inadequate intakes of at least half the nutritional elements. Intakes by children between 2 and 10 years of age, teenage boys, and adult males met or exceeded the reference intakes for the majority of nutritional elements. Intakes by all population groups were well below the reference intakes for all toxic elements.     

Food microbiology: the challenges for the future.

Food microbiology has become a mature science in the twentieth century and has made great advances. While recognising these achievements, it is also necessary to consider how the science may need to change. This paper addresses this by reference to three areas. These are possible changes in foodborne diseases of concern and the impact of molecular and genetic techniques on our current methodology. The recognition of the role of food and associated microbial contaminants in chronic diseases could become a major concern. New developments in our understanding of microbial genetics could affect our concepts of bacterial taxonomy. The current methodologies we use, based upon genotypically identical populations, may need to be addressed. If the trends indicated here are realised, they indicate a major challenge and opportunity for the food microbiologist.     

Role of detection limits in drinking water regulation

Some commentators on environmental science and policy have claimed that advances in analytical chemistry, reflected by an ability to detect contaminants at ever-decreasing concentrations, lead to regulations stricter than justified by available toxicological data. We evaluate this claim in the context of drinking water regulation, with respect to contaminants regulated under the Safe Drinking Water Act (SDWA). We examine the relationships between historical and present maximum contaminant levels and goals in the greater context of detection capability and evaluate the extent to which different aspects of the regulatory apparatus (i.e., analytical capability, cost-benefit analysis, analysis of competing risks, and available toxicological data) influence the regulatory process. Our findings do not support the claim that decreases in detection limit lead to more stringent regulation in the context of drinking water regulation in the United States. Further, based on our analysis of the National Primary Drinking Water Regulation and existing United States Environmental Protection Agency approaches to establishing the practical quantifiable level, we conclude that in the absence of changes to the underlying toxicological model, regulatory revision is unlikely.     

压榨毛布在靴压上的应用与运行

根据高速纸机上靴型压榨的特点和靴套的设计，论述了靴压毛布设计时要考虑的因素，尤其是系统空隙率这一变量参数；提出了靴压毛布使用时清洗和调整的措施。介绍了福伊特（昆山）造纸织物开发设计的靴压毛布新产品的特点与应用效果。