Three of the organic acids - malic, citric and tartaric - were most effective against S. Typhimurium and E. coli O157:H7, more than against L. monocytogenes. With irradiation factored in, the results were significant against all the pathogens.
"We want to determine the least amount of plant extracts that we can use and the least amount of irradiation dosage to get the best inhibitory effect," explained Navam Hettiarachchy, a UA food science professor who supervised the project.
Previous research by Hettiarachchy's research team showed that extracts from grape seed and green tea cut L. monocytogenes to unnoticeable levels when applied in combination with nisin, a bacteriocin recognized as a safe food preservative. The researchers are also using the plant extracts to serve as antioxidants, which minimizes lipid oxidation (the process that causes meat quality to deteriorate by adversely affecting characteristics such as flavour, colour and texture).
Hettiarachchy and its team have examined the effects of irradiation on the chicken's colour and texture and found no significant change. Irradiation, however, has not yet been applied widely in the United States as many companies have worried about potential resistance among consumers.
Hettiarachchy suggested that labels on irradiated products could have a brief explanation of irradiation to educate consumers: "I am hopeful that with time the public will become aware of irradiation processing so that they accept irradiation in processing poultry and meat products for safety against pathogens. A new education component is very important and may be the key for acceptance for irradiated food products by the consumer," Hettiarachchy concluded.
