Bacteriological and chemical quality of water used in carcass washing in Kajiado slaughterhouses in Kenya

Washing carcasses with water at ambient temperature is a common decontamination intervention practiced across many small and medium slaughter facilities (SMS) in Kenya. While carcass washing is primarily done to enhance appearance by getting rid of visible contaminants, when poorly implemented, the intervention has the potential to become a source of contamination by introducing both spoilage and pathogenic bacteria, diminishing beef hygiene. The aim of this study was to investigate the bacteriological and chemical quality of slaughterhouse tap water used in washing beef carcasses in Kajiado slaughterhouses. Previous studies of slaughterhouse water quality in Kenya have not dealt with portable water, major focus being on quality of effluent prior to discharge. Total and faecal coliform, Escherichia coli, Salmonella and Shigella spp. in sampled water were examined with cultural methods. Water pH, temperature, electrical conductivity (EC), total dissolved solids (TDS), turbidity, Iron (Fe), aluminium (Al), fluoride, nitrate, nitrite and ammoniacal nitrogen were determined using several analytical instruments. Three out of five tap water samples (60%) tested positive for E. coli and Pseudomonas aeruginosa while one sample (20%) had isolates confirmed as having Salmonella species. Water sample temperatures ranged between 23.4 and 26.1 ℃ which were over the World Health Organization’s (WHO) regulatory level of 20 ℃. Forty percent of the samples exceeded Fe guidelines, recording 0.35 ppm (M3) and 0.24 ppm (M1C), with the latter also exceeding in EC (2533 ppm), and TDS (1260 ppm). One spring water (M1A) and one borehole water (M2A) sample had ammoniacal nitrogen and fluoride levels of 0.72 ppm and 2.05 ppm, respectively which were beyond the WHO regulatory limit. Aluminium and nitrate levels were low ranging from 0.027 to 0.059 ppm and 0.42 to 2.24 ppm, respectively. Nitrites were not detected. The study concluded that faecal contamination of water intended for beef hygiene and slaughterhouse sanitation operations raises public health concern for the presence of microbial risks including enteric pathogens and opportunistic infections. The study recommends sensitization of slaughterhouse management and local authority on role of water quality in slaughter operations and the establishment of sustainable water treatment and monitoring plans. Additionally, the study recommends further research to investigate seasonality of water quality and sustainable water treatment methods. Key words: Slaughterhouse tap water, carcass washing, chemical water quality, faecal contamination