Acidified sodium chlorite use in carcase wash

Summary

​The antimicrobial activity of acidified sodium chlorite is attributed to the oxidative effect of chlorous acid, which is derived from the conversion of chlorite ion into its acid form under acidic conditions.
The reactions happen instantly on mixing the sodium chlorite with an acid, such as citric or phosphoric acid, and therefore the antibacterial solution needs to be prepared shortly before spraying - the effective shelf-life is less than one hour. Grayson Australia has developed a system which mixes the chemicals immediately before application to maximise the oxidising power of the solution.
Research has shown that using acidified sodium chlorite to sanitize beef trim reductions of 1.4-2.3 log10 E. coli were achieved depending on the feed rate of the spray.
Rockdale Beef Pty Ltd commissioned Grayson Australia in conjunction with Argus Realcold to design a purpose-built spray cabinet for the application of acidified sodium chlorite - Vibrex™ - and install it into the Yanco abattoir.
With the treatment cabinet installed, Rockdale Beef asked Meat & Livestock Australia and Food Science Australia to participate in an investigation of acidified sodium chlorite as an in-line microbiological intervention for beef carcases.
Two trials were conducted for the validation; one on 22nd May 2006 and the second on 25th May 2006.
The validation involved the deliberate application of a cocktail of strains of E. coli that contained no known virulence markers for pathogenic E. coli and which, between them, have characteristics very similar to various known isolates of E. coli O157:H7. The culture was applied to localised areas of six beef sides and the reduction in E. coli numbers was measured through determination of counts prior to treatment with Vibrex™, immediately after spraying carcasses with Vibrex™, and after 24 hours of chilling.
There were no obvious visual changes in either colour or odour of the carcasses. No tests were conducted to assess changes to the taste of cooked meat but indications from published literature suggest this is highly unlikely.
The average overall reductions in numbers of E. coli for the two trials were 1.03 (±0.39 and 1.77 (±0.65) log10 units immediately following application and 3.44 (±0.94) and 3.54 (±0.55) log10 units after chilling. This overall result is a 99.9% reduction in E. coli numbers and was achieved using 1100 ppm Vibrex™ applied at a rate of approximately one litre of final solution per beef side.