MICROBIOLOGICAL QUALITY OF BEEF SUBPRIMALS AS AFFECTED BY LACTIC-ACIDSPRAYS APPLIED AT VARIOUS POINTS DURING VACUUM STORAGE

Beef strip loins were sprayed with 1.5% (vol/vol) lactic acid before a nd/or after 14, 28, 56, 84, and 126 days of vacuum-packaged storage at -1.1 or 2 degrees C to assess the effects on bacteria. Five different treatment combinations including a control (no spray treatment) and o ne treatment with prestorage acid spray followed by poststorage water spray (A/W) were evaluated. Compared to the controls, 97% of all acid- treated loins had lower microbial counts throughout the storage period . Prestorage acid spray (A/0) was more effective than poststorage acid spray (0/A) with the greatest effects (P < 0.05) being observed on da y 28, where the bacterial population was reduced by 1.9 and 1.5 log CF U/cm(2) for loins stored at -1.1 and 2 degrees C, respectively. Microb ial counts for loins with A/A (acid spray both before and after vacuum storage) or A/W treatments were lower than but not significantly diff erent from A/0 (P > 0.05). Poststorage washing resulted in a minimal d econtaminating effect, irrespective of the washing agent used. In addi tion, single spray treatment immediately after fabrication seems more effective and practical than a double spray. Temperature main effects showed that colder temperature (-1.1 versus 2 degrees C) reduced (P < 0.03) microbial growth throughout the storage period. Salmonella conta mination was not detected in any samples; however, 28% of the control and 4% of the spray-treated loins were positive for Listeria spp. Appr opriate time of acid application in combination with colder storage te mperature improved the microbiological quality of meat for at least fo ur weeks.