12, No. 2, 1959) LAUG AND WALLACE: RADIOACTIVE RESIDUES IN FOODS . uffs | is . Sfaten 8 from it, 5% of the original radioactive eoncentration. From these results it appears that a relatively small transfer of radioactivity from the leaves to the infusion occurs. a 0.087 0.005 0.125 0.119 0.234 0.196 0.874 RaDOachyvity 8.8.4) Conclusion § z 5 o 1957 inel. 435 40 ‘48 YEAR Fig. 1—Change in radioactivity of shelifish. The results presented in this report comprise approximately 2000 samples, half of which originated before 1945. Of those sampled after 1945 until the end of 1957, strontium (89 and 90) and cesium 137. In the other sample the percentages were, re- tive regression. hown in Fig. 1. vo samples of rked elevation that the prinwo samples of i the presence jum 95. These monly consumed, (assume normal brew 1 g/100 ml) 100 grams of infusion was made: {a) Sample 13 contained 154 d/m/g tea leaves; the extract from it, 10% of the original radioactive concentration, (6) Sample 21 contained 34 d/m/g tea leaves; the extract Table 5. Resume of total beta radioactivity of tea for August, September, October, November, and December, 1958 | spectrometry Total Beta Radioactivity per Gram Tea Leaves relatively high ‘ted to radiohe total beta 7% and 4.5% ely, by total ave shown ity when samples From 1945 to 1957incl. No. d/m/g 26 32 46 88 0.324 0.364 0.557 31.4 Country d/m curies Far East Japan Formosa India Malaya Ceylon Sumatra Indonesia Java Viet Nam Brazil Peru Kenya Portuguese East Africa | tung fish, No. of Samples Micromicro- Belgian viene? anganyika Tran 66 104 59 8 30 22 20 39 4 South America 37 79 36 28 13 13 6 30 28 11 10 7 6 12 14 13 5 5 3 3 5 4 Africa 10 5 8 11 5 4 8 4 Middle East 14 9 4 4 8 3 3 RADIOACTIVITY d/mAgmn = & mately 10 times the strength of that com- fo & conveyed to the beverage. Under conditions designed to produce an infusion approxi- ia post 45 2.5) o + a tucts described activity in the tea, it became of interest to determine how much radioactivity would be s ears, the indi- BEE ore 45 Because of the surprisingly high radio- a oT own significant at least well Table 4. Of vy a highly sigactivity in the an outstanding a inka spectively, 8.4 and 4.9. Froite Fig. x Vegttabina 2—~Increase foods since 1948. aa Frah in ans Shaltish radioactivity eaARCAs Oty Products v7 of certain (the cutoff date for all samples except tea) it can be seen that fish, sheilfish, dairy products, and tea showed significant increase of radioactivity above the 1945 base line. These results are graphically summarized in Fig. 2. It can be seen that fruits and vegetables showed no noteworthy increases in radioactivity. Since nearly all of the latter had been processed by canning or freezing, there is some question whethersignificant removal of surface contamination may have occurred. Addendum At the time this report was made to the A.O.A.C. in October 1958, a total of 88 samples of tea from various parts of the world had been analyzed; they gave an aver- age total beta value of 31 d/m/g (see Table 4). As of January 1, 1959, nearly 400 additional samples of tea have been examined; the results are given in Table 5. Listed by country of origin, it can be seen that Japanese, Formosan, Malayan, and Indian tea