For many years, one of the UK’s largest food manufacturers has made it their business to be the best at producing all manner of bespoke cooked and raw, ready-to-eat vegetables and carbohydrates for their customers, who include chilled food manufacturers, food-to-go operators and, of course, major supermarkets. Being the best means not only complying with food quality standards set by customers and legislation, but being ahead of them. Water quality is no exception.
What is Cryptosporidium?
The Food Standards Agency requires that the quality of water to be used in food production in England and Wales should comply with the Water Supply (Water Quality) Regulations.
Cryptosporidium is a small protozoan, which infects the gastro-intestinal tract causing sickness and diarrhoea. It is spread by oocysts – a sort of egg with a tough outer shell that protects it from the environment – that can survive for long periods, and which can find their way into water supplies. Consequently food manufacturers go to great lengths to ensure that any water coming into contact with their products is free from the organism. Unfortunately, unlike bacteria, Cryptosporidium is largely unaffected by traditional disinfecting agents like sodium hypochlorite or chlorine dioxide. Taking the lead from the Drinking Water Inspectorate, the DEFRA department responsible for the quality of water supplies, many food manufacturing companies installed 1µm absolute membrane filters as Cryptosporidium barrier. Membrane filtration has two drawbacks. Firstly the filter elements blind quite quickly and replacement is expensive. Secondly, and more importantly, they can remove some bacteria which then grow on the surface of the membrane and penetrate it – a phenomenon called “grow-through”. However, the situation has changed. The Drinking Water Inspectorate, having been presented with overwhelming evidence of its efficacy, has allowed ultraviolet irradiation to be used to destroy Cryptosporidium.
Cryptosporidium: Picture accredited to Science Picture Company
How does UV treat Cryptosporidium?
UV is chemical free, easy to control and more cost effective than other options. However, some customers of food suppliers have been reluctant to accept UV, citing the possibility of “shadowing” – the possibility that organisms can be shielded from the radiation by suspended solids in the water or by poor hydraulic design of the reactor chamber. The Drinking Water Inspectorate also expressed such reservations and adopted guidelines developed by the Environmental Protection Agency in the United States, where UV disinfection has been used for water supply for over ten years. These guidelines require validation of equipment by an independent 3rd party bioassay to strict protocols.
The company uses around 12m3/h for product washing and CIP. Wanting both to minimise risk and to ensure continuity of production if a boil water notice were to be issued in the area, they contacted atg UV.
A chemical-free solution
atg UV‘s solution for this particular food company was an ECP 113-5 medium pressure lamp system that can deliver a UV dose of 40 mJ/cm2 (RED) resulting in a greater than 4 log (99.99%) reduction in Cryptosporidium. Validated to the USEPA and manufactured to meet the strict internal Code of Practice of the end client, the ECP 113-5 system features a 316L stainless steel reaction chamber with an automatic wiper, UV intensity and temperature monitors an integral Spectra II control panel which can interface with most plant and building management systems. The ECP-113-5 meets all the third party validation protocols demanded by the Drinking Water Inspectorate, but the proof of the pudding is in the eating or, at any rate, in the quality control laboratory. The new system has given much better microbiological control and is sufficiently robust to give confidence that it will handle Cryptosporidium if the need ever arises.
The UV supplied is from the ECP range, as pictured above, and features: