J A Mercer, A F Nisbet and B T Wilkins
Publication date: June 2002
In the event of a nuclear accident, the Food Standards Agency (FSA) is responsible for ensuring that consumers are protected from exposure to radiation as a result of contamination in the foodchain. Milk is an immediate priority due to the rapid transfer of some important radionuclides from pasture to milk and the importance of milk in the diets of infants and young children. Thus, following an accidental release of radionuclides, FSA's initial response would be to issue precautionary advice concerning the restriction of the sale and consumption of milk within 24 hours of the start of the accident. This advice would mean that large volumes of milk with activity concentrations less than intervention levels could be held up until reliable test results were obtained to confirm that the milk was suitable to enter the foodchain. Special arrangements would be made for the collection of milk from the affected area and this milk would be segregated from that known to be uncontaminated and stored at depots. With limited storage capacity, this milk may have to be disposed of unnecessarily, unless an emergency monitoring programme could be initiated soon after an emergency is declared.
In addition, if the level of contamination in foods exceeded the relevant intervention level then the food would be removed from the foodchain and would require disposal. The quantity of food affected by such restrictions could be substantial. In particular, the disposal of milk may present a significant problem, as it is produced daily and in large quantities throughout the country.
This report evaluates three possible ways in which the quantity of milk designated as waste could be reduced. The three approaches considered are:
Various options regarding the development of a suitable milk monitoring system have been considered by the Agriculture and Food Countermeasures Working Group (AFCWG). A purpose-built milk monitoring kit developed by NRPB would be highly effective at releasing large volumes of 'clean' milk back into the foodchain. The effectiveness depends on the identification of all producers in the affected area, the distribution routes of milk from that area and the availability of small samples of milk from each producer for analysis at a regional depot. It is recommended that contingency plans for the emergency monitoring of milk be drawn up on a regional basis by the dairy industry.
The direct decontamination of milk offers one approach for returning contaminated liquid milk to the foodchain. This could be important if supplies of 'clean' milk became limited. MAG*SEP SM is a relatively new process that selectively removes radionuclides from aqueous liquids, through adsorption on to a resin followed by magnetic filtration. MAG*SEP SM operates commercially in the Ukraine for the removal of radiocaesium from milk and unlike other decontamination treatments does not affect the smell, colour and nutritional quality of the milk. Nevertheless, the acceptability of this and other decontamination techniques to stakeholders was found to be low.
Milk processing facilities are widespread in the UK and offer an alternative approach for returning uncontaminated milk products to the foodchain. The production of dairy products that would be considered suitable for the foodchain often results in large volumes of contaminated liquid by-products being produced that would need to be disposed of carefully. The issue of waste disposal could limit the practical implementation of this option. Furthermore, stakeholders are opposed to techniques that derive food products from contaminated raw materials.
An alternative use of processing facilities would be for the conversion of liquid milk into more stable end products that could be stored prior to disposal. Whole milk powder would be the preferred option as it is easy to transport and store, offers a large mass reduction over liquid milk and has no associated contaminated by-products. In situations where the capacity to dispose of contaminated raw milk is limited, conversion to whole milk powder may provide a useful mechanism to delay disposal.
This study was funded by the Ministry of Agriculture Fisheries and Foods, the Food Standards Agency, the Environment Agency and the National Radiological Protection Board.
Last reviewed: 29 July 2009