Effect of lactic acid On Escherichia Coli O157: H7 and on color stability of vacuum-packaged beef steaks under high storage temperature

Abstract

The effect of lactic acid (LA) addition on Escherichia coli O157:H7 survivability as well as the color stability was determined in vacuum-packaged beef steaks storage at 10°C for 50 days. Longissimus dorsi muscle was portioned into beef steaks and inoculated with Escherichia coli O157:H7. Afterwards, the samples were submitted at three treatments: without lactic acid addition or non-treated (NT); with 0.56 M (5%, v/v) (L5), and with 1.13 M (10%, v/v) (L10) of lactic acid addition. Same division was performed with samples non inoculated. All samples were package at vacuum and stored at 10°C during 50 days. L10 demonstrated an efficient bacteriostatic effect (P < 0.05) against E. coli O157:H7 and total aerobic mesophilic bacteria. Nonetheless, LA induced a decrease (P < 0.05) in a* values in samples after application and during storage, promoting discoloration of beef steaks. Therefore, L10 was efficient in controlling E. coli O157:H7 even at abusive storage temperatures. However, this decontamination treatment affects negatively the color stability of beef.