Market Basket Survey/Study

Methyl parathion is approved only for use on crops. The maximum amount of methyl parathion residue allowed by the Food and Drug Administration (FDA) and EPA on crops used as food is 0.1-1 ppm. The FDA has monitored the food supply for pesticides for a number of years. FDA purchases many kinds of foods through Market Basket Surveys and analyzes them for residue levels of pesticides. These FDA studies allow scientists to estimate the daily intake of pesticides. Generally, the FDA monitoring studies conclude that the U.S. food supply contains only very small amounts of pesticides that are not a concern. However, there have been some reports of the illegal use of methyl parathion inside homes. For more information, see Section 1.7 and Chapter 6. 

Case study (Organophosphates Market Basket Survey)... 

Pesticide residues consist of chemicals that might occur in a commodity as a result of application of a pesticide. Such chemicals typically correspond to compounds for which a regulatory agency has or will set a tolerance, i.e., a maximum residue limit, specific to the commodity. In either a field study or a market basket survey, residues to be determined will be those which result from application of the specific pesticide that the study is intended to support. A market basket survey, however, might be intended to support not just one but several different pesticides of the same or different chemical classes. In addition, a market basket survey might include pesticides not used in the USA but for which import tolerances exist. For example, some uses of the parathion family of pesticides on food products have been abandoned in the USA but remain in other countries that export the products to the USA. A market basket survey offers a means to evaluate actual dietary exposures to residues of such pesticides. In addition, tolerance expressions frequently include multiple compounds, all of which must typically be determined in residue field trials. The sponsor of the market basket survey must decide whether to analyze for all compounds in the applicable tolerance expression or to restrict the program to selected analytes, such as the active ingredient. 

As with any residue method, a method used in an LSMBS method should include analysis of control commodities to demonstrate adequate selectivity and analysis of fortified control samples to demonstrate recovery. These aspects present a particular challenge in every food-based market basket survey, because, unlike field residue studies, control samples of known provenance are not available. 

A market basket survey, however, is unique in that untreated control commodities, as the term is normally used in residue studies, cannot be obtained. In a market basket survey, food commodities are collected at the consumer level and not from controlled field tests. By design, the cultural and treatment details for the collected commodities are expected to differ from sample to sample. This factor enables the collected commodities to represent the spectrum of conditions under which crops are supplied for human consumption. 

Best practices in the implementation of a large-scale market basket residue survey study... 

Published surveys include a UK Total Diet Study in 1983.24 This estimated that the total daily dietary exposure to PAHs was around 3700 ng/person, with BaP contributing 250 ng/person. Similar figures have been reported for the Netherlands, where a total diet study found that the average daily dietary exposure to PAHs ranged from 5000 to 17,000 ng/person.25 A market basket study of components of the Italian diet found that the average daily dietary exposure was 3000 ng/person.26... 

The principal surveys on food have been market-basket or Total Diet Studies (see Chapter 7) to determine the average dietary exposures of national populations. There are values for average exposure from the UK diet for 1982, 1992 and 1997 the 1982 samples being measured at the same time as the 1992 samples to ensure comparability. These studies have shown that average... 

The FDA has also performed its Total Diet Study annually since 1961. This study involves a market basket collection of foods from four chosen geographical regions and three cities in each region per year. Each market basket is comprised of 261 different food samples and the foods are prepared for table-ready consumption prior to analysis. Estimates of daily exposures of population subgroups to pesticide residues in the diet are attained by considering the results of the Total Diet Study samples and food consumption estimates obtained from national food consumption surveys (FDA, 2000). 

Meat does not usually have a high iodine content, but reported values vary widely (e.g., 1.6-260 pg/kg for average values in two different studies) (3). EDDI can increase muscle iodine several fold. Koutras (4) reported 6.5 pg iodine per portion in meat dishes in Athens. Meat, fish, and poultry combined provided 111 pg iodine per day, calculated for an adult ingesting 2,850 calories, from the market basket diet of 1978 (2), but only about 30 pg in the 1989 survey (1). However fast food" has been reported to have extremely high iodine contents, up to 4,300 pg in a frozen fried chicken dinner. These amounts probably include iodine from bread, food processing, salt, and food coloring some of the latter may not be bioavailable. 

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