Food, radioisotopically labeled

Immunochemical methods that utilize radioisotopic labeling can detect the use of anabolic sex hormones that increase the growth in meat animals. Stilbene [588-59-0], C14H12, trenbolone [10161-33-8], and zeranol [55331-29-8], C18H2605, can be successfully monitored by these immunoassay techniques (45). In order to prevent veterinary dmgs from being transported to the human food chain, radioisotopic immunoassays were developed to monitor veterinary antibiotics such as penicillin and chloramphenicol [56-75-7], C H CyX C, in meat, milk, and eggs (qv) (see Antibiotics Meat products Milk AND MILKPRODUCTS). 

Coleman, D. C. 1970. Food webs of small arthropods of a broomsedge field studied with radioisotope labelled fiingi. pp. 203-207. In Methods of Study in Soil Ecology. UNESCO, Paris. 

Radioisotope techniques have allowed precise measurement of dietary iron absorption. Initial studies utilized test meals of individual food which had been intrinsically labeled with radios active iron prior to harvesting (1,2). Utilization of these single food meals allowed a rank order to be established among the tested foods. Subjects could serve as their own controls when an identical reference dose was given to each subject. 

Results of this study have verified and extended the suggestion made in previous radioisotope food chain studies. . . that the shape of the uptake curves [Figure 80b] can be indicative of the trophic position of a population of consumers in the field. Thus, populations known to be strictly herbivorous reach a peak of radioactivity very soon after the primary producers have been labelled, while known predators such as spiders show delayed uptake at lower levels. Intermediate patterns could then be interpreted as indicating feeding from more than one trophic level. 

Molybdenum consists of seven stable isotopes, Mo, Mo, Mo, Mo, Mo, Mo, and °°Mo, with average natural abundances of 14.77, 9.23, 15.90, 16.68, 9.56, 24.19, and 9.67%, respectively. Half-lives of molybdenum radioisotopes are in general not long enough (<67 h) for kinetic studies or intrinsic labeling experiments. So far, only a single study has been conducted to compare molybdenum absorption from extrinsically and intrinsically labeled foods [282]. Absorption of both labels was statistically not different for kale. For soy, however, the intrinsic label was less well absorbed and less well excreted than the extrinsic label given as Mo-molybdate. 

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