A double-bed process for the removal of cationic fission products from milk

Abstract

A process for the removal of cationic fission products from milk is described in which no prior acidification is necessary. The milk is treated at 40 °C by 2 beds of suitably charged cation exchange resins, one of which is of the carboxylic acid type and the other of the sulphonic acid type. On the first bed all the metallic cations of the milk are replaced by K+and H+, and on the second the ionic composition is restored. During processing the pH is reduced from 6-8 to approximately 6-2 and is restored to 6-8 by the addition of alkali metal carbonates to the milk after treatment.On a pilot plant of capacity 1600 1 (30 resin bed volumes) per 5-h day it was found that the radiochemical efficiency was approximately 80 % for 85 Sr and 97 % for 137 Cs.The process caused some losses of vitamins, especially of thiamine, and an increase in the lead, copper and iron contents all of which, however, were at an acceptable level. Other changes in chemical composition were negligible and enzymic clotting time remained unchanged. Flavour and appearance of the product were satisfactory and it was satisfactorily both roller-and spray-dried. The process is discussed with reference to an earlier method in which prior acidification is necessary. It is concluded that the double-bed process is somewhat more efficient for the removal of fission products and that a full-scale plant would be little or no more expensive to erect and only slightly more expensive to operate.A process for the removal of cationic fission products from milk was patented in 1962 by Murthy, Campbell, Mazurovsky & Edmondson, and plants based on this process have been set up both in America Producer's Creamery Company, 1965) and in Britain (Glascock, Hall, Suffolk & Bryant, 1968). The method consists essentially of the passage of milk, acidified with citric acid to pH 5-2-5-3, through a cation exchange resin of the sulphonic acid type charged with a suitable mixture of the ions of Ca, K, Na and Mg. The ionic composition of the resin is chosen so that little or no change in the ionic composition of the milk occurs except that 96-98 % of the ^Sr and about 75 % of the 137 Cs are removed. Milk treated in the pilot plant set up in Britain has been subjected to analysis and to tests of its nutritional quality (Braude, Glascock, Newport & Porter, 1969). Although the analysis revealed no change in composition likely to prove deleterious 218 R. F. GLASCOCK AND D. T. W. BRYANT to the consumer, it was concluded from experiments with baby pigs that the nutritional value of the milk was adversely affected by treatment in the plant. This adverse effect was shown by a higher mortality in the animals given treated milk than in those given untreated milk, although post-mortem findings in both groups revealed no specific cause of death. These results were not in agreement with those of American workers (Isaaks et al. 1967), who, however, gave their animals a much smaller ration which, as is suggested in the paper by Braude et al. (1969), may have masked the effect observed in our ...

The Removal and/or Reduction of Radionuclides in the Food Chain

“…Their study emphasized the important effect of the volume of treated milk so that when 30 resin bed volumes (rbv) and 15 rbv were treated, the concentration of residual Cs was reduced from 30% to 1 % (16). This process was later improved (17) by the use of a double bed: the first, of a carboxylic acid type, retained all the metallic cations and the second, of a sulphonic acid type, restored the ionic composition of the milk. Some losses of vitamins were observed, with an increase in Pb, Cu, and Fe.…”

Water-soluble vitamins in milk and milk products

“…A process for the removal of cationic fission products ( 85 Sr and 137 Cs) from milk has been described by Glascock & Bryant (1971). The milk was treated at 40 °C with 2 beds of cation exchange resins, one of which was of the carboxylic acid type and the other of the sulphonic acid type.…”

Some effects of processing and storage on the nutritive value of milk and milk products

“…The removal of these isotopes may be effected by ion-exchange resins, but the procedure causes losses of some vitamins, particularly of thiamin, of which about two-thirds is lost, and these must be restored before use. The nutritional quality of milk treated by passage through a cation-exchange resin (Murthy, Campbell, Mazurovsky & Edmondson, 1962) was found to be adversely affected in tests with baby pigs (Braude, Glascock, Newport & Porter, 1969), but subsequent elaboration of the procedure through the use of a mixed-bed column containing anionic-and cationicexchange resins gave a product that allowed normal growth in young pigs, rats and monkeys (Glascock & Bryant, 1971 ;Cohen, Ashworth, Bryant & Glascock, 1973). …”