Purpose: The purpose of these experiments was to define the optimal application parameters for acidified sodium chlorite (ASC) applied to beef sub-primals and parts and trim within a processing plant.
Methods: Portioned (100 cm2) beef sub-primals or parts and trim were inoculated with United States Department of Agriculture Food Safety Inspection Service approved pathogenic surrogate organism (5 Escherichia coli strains, 5 log CFU/cm2). Sub-primal samples were stored at 4°C or -20°C and tempered at 4°C (6 h) before conditioning and treatment. The surface of sub-primal samples was conditioned with water or a peroxyoctanoic and peroxyacetic acid mixture (POAA; 180-210 ppm, 1-2 s) directly before treatment with ASC (800 – 1100 ppm, pH 2.35 – 2.50) acidified with citric acid (CA) or sodium acid sulfate (SAS). ASC was applied in-plant to beef sub-primal samples within a top and bottom spray cabinet at 6.8, 7.9, 11.4, or 18.9 l/min for 18 or 30 s. Beef parts and trim were stored at 4°C and treated through an auger application system at 13.2 l/min for 15 s. Surviving E. coli (2 plants, 2 replicates per plant, 3 samples per repetition) were enumerated from samples after treatment. Counts (log CFU/cm2) were analyzed in the general linear model of Minitab and means were separated (α=0.05) using Fisher’s least significant difference.
Results: Fewer E. coli (P < 0.05; 0.4-0.5 log CFU/cm2) were recovered from sub-primals stored at 4°C than from those that were frozen and tempered (application surface temperatures of 4.3±1.0°C and -1.0±0.3°C, respectively). In general, conditioning the sub-primal surfaces before ASC treatment with water or POAA treatment and increasing the application volume above 6.8 l/min did not enhance (P ≥ 0.05) its efficacy. CA may be preferred as the acidulant of ASC as fewer (P < 0.05) E. coli were recovered from sub-primals (0.5-0.7 log CFU/cm2) and parts and trim (1 log CFU/cm2) than when SAS was the acidulant.
Significance: These data may be used for the in-plant validation of ASC and indicate the optimal surface temperature, application volume, and acidulant for ASC when applied on beef sub-primals and parts and trim.