Calcium sulfate may limit C. jejuni contamination of fresh poultry.

C. jejuni is a leading cause of acute bacterial gastroenteritis in the United States and many developed countries. Epidemiologic studies have identified poultry as a leading means of transmitting the pathogen. But it appears that an acidic calcium sulfate-based formulation may be a highly effective treatment for reducing the C. jejuni contamination of fresh poultry.

Scientists at the University of Georgia individually tested glycerol monolaurate, hydrogen peroxide, acetic acid, lactic acid, sodium benzoate, sodium chlorate, sodium carbonate and sodium hydroxide for their ability to inactivate C. jejuni in pure culture. A treatment at 4 C for up to 20 minutes with 0.01% glycerol monolaurate, 0.1% sodium benzoate, 100 mM sodium chlorate or 1% lactic acid did not significantly reduce C. jejuni populations. But treating the product with 0.1% and 0.2% hydrogen peroxide reduced C. jejuni levels by about 1 [log.sub.10] cfu per ml and 3 [log.sub.10] cfu per ml, respectively.

Treatments composed of 0.5% acetic acid, 25 mM sodium carbonate or 0.05 N sodium hydroxide reduced C. jejuni levels by more than 5 [log.sub.10] cfu per ml within 2 minutes. Combinations of 0.5% acetic acid and either 0.05% potassium sorbate, or 0.5% acetic acid plus 0.05% sodium benzoate, reduced C. jejuni populations by more than 5 [log.sub.10] cfu per ml within 1 minute. A combination of acidic calcium sulfate, lactic acid, ethanol, sodium dodecyl sulfate and polypropylene glycol also reduced the number of C. jejuni by more than 5 [log.sub.10] cfu per ml within 1 minute.

All chemicals or combinations of chemicals for which there was greater than a 5-[log.sub.10]-cfu-per-ml reduction in pure culture were further evaluated for their antimicrobial activity to C. jejuni on chicken wings at 4 C. A treatment of 2% acetic acid for up to 45 seconds reduced C. jejuni levels by about 1.0 [log.sub.10] cfu per g. A treatment of 100 mM sodium carbonate for up to 45 seconds reduced the amount of C. jejuni by 1.8 [log.sub.10] cfu per g.

Treatments using 0.1 N sodium hydroxide for up to 45 seconds reduced C. jejuni populations by 3.0 [log.sub.10] cfu per g, and a polypropylene glycol treatment for 15 seconds reduced the population of C. jejuni by 5 [log.sub.10] cfu per g. An additional study was done with chicken wings that were heavily inoculated with C. jejuni and held at 4 C for 24 hours before they were treated with polypropylene glycol. This treatment inactivated 5 [log.sub.10] C. jejuni per g within 15 seconds.

Further information. Michael Doyle, Center for Food Safety, University of Georgia, Griffin Campus, Melton Building, Griffin, GA 30223; phone: [phone]; fax: [phone]; email: [e-mail].