Evaluation of chemical immersion treatments to reduce microbial populations in fresh beef.

The aim of the current study was to assess the ability of a number of chemicals (acetic Acid (AA), citric acid (CA) lactic acid (LA), sodium decanoate (SD) and trisodium phosphate (TSP)) to reduce microbial populations (total viable count, Campylobacter jejuni, Escherichia coli, Salmonella typhimurium and Listeria monocytogenes) on raw beef using an immersion system. The following concentrations of each chemical were used: 3 & 5% for AA, CA, LA, SD and 10 &12% for TSP. Possible synergistic effects of using combinations of two chemicals sequentially (LA+CA and LA+AA) were also investigated. L*, a* and b* values were measured before and after treatments and ΔE* values were calculated in order to determine any changes in the color of meat due to the use of these chemicals. In general, all chemical treatments resulted in significantly (p<0.05) reduced bacterial counts when compared to untreated controls. The greatest reductions were obtained by using LA3%, SD5%, AA5%, LA5% and SD3% for TVC, C. jejuni, E. coli, S. typhimurium and L. monocytogenes, respectively. However, no significant difference in microbial load was observed between the different concentrations of each chemical used (p>0.05). The application of combinations of chemical immersion treatments (LA3%+AA3% and LA3%+CA3%) did not result in further significant reductions in microbial populations when compared to single chemical treatments (P<0.05). Assessment of color changes in meat following the application of chemical immersion treatments indicated that using AA or CA at either concentration and LA at 5% led to an increase in the ΔE* value of >3 immediately after treatment and after 24h storage. The remaining treatments did not result in significant changes to the color of raw beef.