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Factory hygiene - novel decontamination techniques From June 2010 newsletter

Food Factory hygiene – novel decontamination techniques

Effective decontamination of facilities is important for assuring food safety and reducing spoilage. Some microbial strains have become persistent in food production areas and novel techniques are needed to control them. Amongst the relatively new ideas that we have been exploring to supplement traditional techniques is that of decontaminating the processing area as a whole. Alicja Malinowska of our Food Hygiene Department explains:

"We have focused on 'whole room' systems using vaporised hydrogen peroxide and ozone, which are available commercially, to explore their practical application in the food and drink industry. We are developing guidance on the range of systems available, their selection and their use for whole room disinfection. This research will also allow us to provide industry with a highly relevant technical contract service.

We have found that vaporised hydrogen peroxide is a very useful dry process – for example, in facilities where electronic equipment and sensitive materials cannot withstand liquid applications. It was excellent against spores and also gave significant reductions of Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes. However, we noted possible resistance of some microorganisms.

Ozone spontaneously decomposes to oxygen and so is appropriate for use in food production areas. It requires high humidity and is most effective in a temperature-controlled environment – its stability decreases as the temperature increases. In laboratory trials, microbial reduction was directly related to ozone concentration and contact time. It was found that higher levels for several hours may be appropriate for wholeroom disinfection of Listeria spp. Ozone use was also trialled in three factory visits, where it was found to be effective in reducing general microbial contamination of environmental surfaces. A 4–week continuous factory trial demonstrated an average reduction equivalent to that previously obtained with quaternary ammonium compounds."

Advice to clients

The experience gained from these studies has allowed us to offer a service to validate the efficacy of whole room disinfection systems in food factories – either for routine factory decontamination, following a contamination incident, or as a replacement for traditional disinfection.