Application of hazard analysis critical control point (HACCP) concept to study cattle slaughterhouse hygiene and Carcass contamination in Zambia

Abstract

The Hazard Analysis Critical Control Point (HACCP) concept was applied for the first time to four Zambian cattle slaughterhouses to study slaughterhouse hygiene and bacterial contamination of carcasses. Swabs were collected from carcass surfaces and also from the following environmental surfaces, which were likely to come in contact with carcasses: knives, cutting saws, tables, walls, floors, aprons and worker's hands. Samples were collected from animals at the following operational points: before skinning; after skinning; after evisceration; and after carcasses were chilled for 24 hours. At each operational point, four sites were swabbed except for point A were only two sites were swabbed. Similarly, four different sites were swabbed from each environmental surface per visit. A total of 2176 swabs were collected from 72 carcasses, and 96 swabs from the above mentioned environmental surfaces from slaughterhouses A and B. Observational results for various hygiene categories where scored for slaughterhouse A, B, C and D. Slaughterhouses A and B, in which microbiological contamination analyses were done, had overall mean aerobic plate count, mean total coliform count, and mean coliform count ranges of logio3.67 - 4.14/cm^; logio 1.63 - 2.44/cm^ and logio 1.23 - 1.59/cm^ respectively. Municipal slaughterhouses C and D, with no defined slaughter and dressing procedures, recorded lowest hygiene assessment scores (18.7% and 21.3%) of hygiene satisfaction, respectively). Carcasses that recorded zero duplicate coliform count after skinning were in the range 25 - 30% where as zero duplicates after evisceration ranged from 15-20.3%, Effect of chilling as a critical control point was better illustrated by changes in means of total coliform count (logio 184 to 0.00) and faecal coliform count data (logw 2.5] to 0.00/cm^) than aerobic plate count data (logw 4.10 to 3.82/cm^). Salmonella was isolated from carcasses at all sampling points with skin samples recording high isolation frequencies.The results of this study indicate that neither aerobic plate count nor total coliform counts alone is sufficient to analyse carcass contamination levels at various operational points but the two, however, are complimentary. This study has also demonstrated high levels of bacterial contamination on carcasses, which is known to be associated with poor hygiene. There appears a need to establish slaughter and dressing procedures, and quality assurance programmes based on risk assessment and maximum utilisation of resources. Meat standards also need to be set and this will need an active legislative support to improve both meat safety and quality, and hygiene standards in Zambian cattle slaughterhouses.