Purpose: This study evaluated the efficacy of increasing concentrations of lactic acid (88%, Birko Corporation) to reduce STEC contamination on chilled beef subprimals when applied as a spray prior to vacuum packaging and after 24 h of wholesale bagged storage.
Methods: Beef strip loins (n= 12) were inoculated with a 7-serogroup STEC cocktail, (30 min attachment). Subprimals were sprayed with increasing concentrations of LA (3.0-10.0 % at 0.5% intervals) or a water control (0%). Meat surface excision samples and color readings (L*, a*, and b*) were obtained from each subprimal post-inoculation, 5 min after a LA spray, and after 24 h of vacuum packaged storage. Three replications were performed.
Results: LA spray reduced STEC contamination on subrimals by 0.2 – 0.7 log CFU/cm2 (initial level of ca. 5 log CFU/cm2). All LA concentrations except 3 % produced a higher population reduction (P ≤ 0.05) compared to water. No differences (P > 0.05) were observed in reductions among LA concentrations of 3.5 -10 %. After chilled vacuum packaged storage, subprimal STEC populations did not change (P > 0.05). Application of higher concentrations of LA reduced (P ≤ 0.05) L* and b* color values compared to the water control; similar results were observed after the 24-h chill period.
Significance: LA sprays ≥ 3.5% may reduce STEC contamination on chilled beef subprimals (by <1 log cycle), but application of higher concentrations provided similar reductions and may negatively impact product color.