Preslaughter spray-washing effects on physiological stress responses and skin and carcass microbial counts in goats

Abstract

Preslaughter management procedures that decrease fecal contamination of skins/hides are likely to reduce biological hazards on carcass surfaces during slaughter and processing. This trial was conducted to determine the effects of preslaughter spray-washing on stress responses and skin and carcass bacterial counts in goats. Twenty meat goats were slaughtered in two groups (replicate) on 2 different days (10 goats/replicate). Animals were randomly allotted to treatment (1 min spray-wash) or control (no wash) groups ( n = 5/(treatment replicate)). Blood and skin swab samples were collected from control and treated animals before and after the washing treatment. Bacterial counts on the carcasses immediately after dressing were also recorded. Treatment, sampling time or treatment × sampling time did not affect the plasma cortisol, glucose and non-esterified fatty acid (NEFA) concentrations. Skin aerobic plate counts were the same in both treated and control groups prior to washing treatment, but were significantly less in the treated group when sampled after washing (treatment × sampling time, P < 0.05). Aerobic plate counts were 3.6 and 4.4 log 10 CFU/cm 2 in the treated and control groups, respectively. However, skin Escherichia coli counts did not significantly decrease due to spray-washing treatment. Spray-washing treatment also did not influence carcass E. coli or aerobic plate counts. Results indicate that skin bacterial counts can be significantly reduced by preslaughter spray-washing, without increasing stress in goats. Preslaughter spray-washing may be a cost-effective skin decontamination method that can be easily adopted in goat slaughter plants.