Effect of Pre-and Post-Slaughter Lactic Acid Spray on Microbial Population Reductions and Quality Characteristics of Lamb Carcasses

The sheep fleece serves as the primary source of carcass contamination. In this study, before and after slaughter, lactic acid was sprayed for microbial decontamination for lamb carcasses. Eighteen male lambs were randomly assigned to two groups: a treatment and control groups. Each treatment group consisted of six lambs that received sprays of 3% or 6% lactic acid in two distinct phases: (I) applied to a live animal's hide/fleece and (II) was applied to carcass surfaces immediately after slaughter. Remaining six animals, the no-spraying treatment was used as the control group. Microbiological samples were then collected from animal skins or fleece before spraying, and carcass surfaces 24 h after slaughter. The characteristics of the meat quality were also analyzed. Total aerobic counts, coliforms, Escherichia coli, Bacillus, Pseudomonas, and Staphylococcus were detected in both the external hide/fleece and the carcass surface samples. Nonetheless, treatments involving lactic acid sprays markedly decreased counts of all examined microbes on carcass surfaces compared with the non-sprayed control group. Treatments involving 3% and 6% lactic acid sprays reduced Escherichia coli and total coliforms counts by 2.36, 2.51, and 2.67, 2.71 cfu/cm2 of the carcass surfaces, respectively. Likewise, treatments spraying with 3% and 6% lactic acid treatments led to reductions of 4.20 and 4.31 cfu/cm2 for the populations of total aerobic count, 1.72 and 2.06 cfu/cm² for Pseudomonas, 2.02 and 2.06 cfu/cm² for Bacillus and 1.83 and 2.75 cfu/cm² for Staphylococcus, respectively. No significant differences were observed in the physicochemical sensory attributes between the control and spray treatments indicating that spraying lactic acid application pre-slaughter did not cause stress to the animals. Spray application of lactic acid pre- and post-slaughter stages is practical and can be used for optimizing food safety as it effectively ensures reduce bacterial contamination of lamb carcasses without negatively impacts the quality.