March 28, 2007

US study show steam cleaning reduces salmonella in meat

Using commercial household steam cleaning can provide smaller processing plants an economical method of bacteria decontamination on freshly slaughtered beef and hog carcasses, according to scientists from the University of Georgia in the US. 

The study concludes the discovery could offer a relatively simple yet effective way for smaller scale meat processors to meet strict food safety controls.

Tests were conducted on 72 beef and 72 hog carcasses from four small or very small processing plants. Three sites on one side of each carcass were exposed to 60 seconds of steam treatment, while the other side remained untreated.

Prior to treatment, salmonella was found in five of the carcasses but all tested negative for the pathogen after steam exposure. Samples were taken before, immediately after and 24 hours following the steam treatment.

It found that aerobes, coliforms, and enterobacteriaceae at the three anatomical locations on both types of carcasses have decreased following steam treatment.

Aerobes are bacteria and high levels can indicate possible contamination, while coliforms are a common bacterial indicator of sanitary quality of food and water as they are found in animal feces. Enterobacteriaceae is the family of bacteria that includes salmonella and Escherichia coli (E.coli).

Samples taken from the beef carcasses prior to treatment were found to contain mean populations of aerobes, coliforms, and Enterobacteriaceae of 1.88, 1.89, and 1.36 log CFU/cm2, respectively. Immediately after treatment populations fell to 1.00, 0.71, and 0.52 log CFU/cm2, and tests after 24 hours found 1.10, 0.95, and 0.50 log CFU/cm2 remained.

On the other hand, tests on hog carcasses before exposure to steam were also found to have mean populations of aerobes, coliforms, and Enterobacteriaceae of 2.50, 2.41, and 1.88 log CFU/cm2, respectively. Immediately after treatment populations fell to 0.50, 0.94, and 0.21 log CFU/cm2, and tests after 24 hours 0.91, 1.56, and 0.44 log CFU/cm2 remained.

The bacteria found on pre-treated beef carcasses were generally found to be highest on midline, then neck, followed by rump while most bacteria for hog carcasses, most bacteria were found on the belly, then jowl, followed by ham.