Chemical Composition, Bacterial Load And Prevalence of Verotoxigenic Escherichia coli in Donkey Meat Sold at Ezzamgbo, Ebonyi State Nigeria

ABSTRACT

This study was carried out to evaluate the chemical composition and bacterial load of donkey meat as well as the prevalence of verotoxigenic Escherichia coli (VTEC). The study adopted the survey and experimental designs. A questionnaire, which comprised three sections, was developed to elicit information on the demographics, source of meat, and factors that influence choice of meat consumed by the respondents. The instrument for data collection was validated by three experts. A pilot study was conducted and the Cronbach Alpha Reliability Coefficient of 77.5% was determined. Four hundred and fifty copies of the questionnaire were administered to respondents in Ezzamgbo who were selected by a simple random sampling technique. This comprised meat sellers (117), butchers (36), farmers (72), civil servants (130), students (68), artisans (18) and donkey hide sellers (9). Systematic random sampling was employed to select 60 donkeys at slaughter. From each of the selected donkeys, three meat cuts (shank, sirloin and ribs) giving a total of 180 meat samples were collected and processed for chemical composition and bacteriological analysis. The meat cuts were analysed for mineral content, percentage moisture, protein, fat and ash. The bacterial load of the meat was evaluated by mean aerobic plate count (APC) on nutrient agar and mean coliform count (MCC) on MacConkey agar. Suspected E. coli isolates were characterized by conventional biochemical tests and Analytical Profile Index (API). Confirmed E. coli were presumptively identified as VTEC on sorbitol MacConkey agar (SMAC). The prevalence of VTEC O157 and non O157 was determined using specific latex agglutination test. The resistance profiles of the isolates to commonly used antibiotics were evaluated using the disc diffusion method. The chemical composition and bacteriological survey were subjected to one way analysis of variance and significant means were separated using Duncan’s multiple range test at the significance level of p < 0.05. The factors that influence the preference for meat type were affordability, tenderness and flavour. The brightness of the meat, availability and religious and cultural restrictions had no direct influence on the choice of meat type. Forty-four, forty-one and forty-nine percent of the respondents indicated that beef, donkey and chevon, respectively are cheap and affordable. Seventy-four percent of the respondents indicated that the hike in price of beef was influenced by the insurgence in Northern Nigeria while Fifty-three percent indicated that the insurgence in the North has influenced the price of donkey meat and chevon. Sixty nine, forty and sixty-eight percent of the respondents indicated that beef, donkey meat and chevon, respectively are soft and tender but eighty percent indicated that chevon have good aroma or flavour while sixty-two and thirty-five xv percent stated that beef and donkey meat have good aroma. There were no significant differences (p > 0.05) in the iron content and percentage moisture and protein between the various meat cuts. There were significant differences (p > 0.05) in zinc, magnesium, calcium and phosphorus contents and percentage ash and fat between the meat cuts. The mean values of the chemical composition of donkey meat were 74.11±1.20% moisture, 1.73±0.50% ash, 21.37±0.79% protein and 2.30±0.22% fat, 3.76±0.47 mg/100 g zinc, 4.27±0.30 mg/100 g calcium, 3.04±0.21 mg/100 g magnesium, 0.60±0.06 ppm iron and 0.046±0.01 ppm phosphorus. The mean APC for the meat cuts were 1.2 x 108 ±2.35 x 107 cfu/g, 9.16 x 107 ±2.01 x 107 cfu/g and 1.08 x 108 ±2.27 x 107 cfu/g for the shank, sirloin and ribs respectively. There were no significant (p > 0.05) differences in the mean APC values between the different meat cuts. The MCC of the rib (2.47 x 107 ± 5.26 x 106 cfu/g) was significantly higher than those of the shank (1.94 x 107 ± 4.28 x 106 cfu/g) and sirloin (9.90 x 106 ± 2.16 x 106 cfu/g). A total of 108 E. coli isolates, comprised 52 from the shank, 30 from the sirloin and 26 from the rib, were obtained from the 180 meat samples. Thirty-seven of these isolates were sorbitol negative out of which 28 were confirmed VTEC O157:H7 while 16 were confirmed non-O157: H7. The overall prevalence rate of VTEC O157:H7 was 15.56%. Resistance to ampicillin, streptomycin, amoxicillin/clavulanic acid and tetracycline were exhibited by 100, 85.71, 78.5 and 42.86%, respectively of the VTEC O157:H7 strains. It was concluded that the factors that influence individuals’ choice of meat are availability, price, flavor, brightness, and health related issues. Religious and cultural sentiments had little influence on the consumption of meat generally. Donkey meat is frequently masked as beef and sold to unsuspecting consumers. Donkey meat is nutritional wholesome as it contains high protein, ash, zinc, calcium, magnesium, phosphorus and iron. Donkey meat sold at Nkwo-Jaki is unsafe for human consumption using the bench mark of microbial standard. The contamination of the meat is associated with the health status of the animal, the environment and the personnel handling the meat. The prevalence of 15.56% of VTEC and 8.89% of nonO157 makes donkey meat sold at Nkwo-Jaki unsafe and may pose a threat to the health of individuals who consumes the meat. The high level of resistance of the bacterial isolate in this study shows that there is possibility of indiscriminate use of antibiotics in donkeys or the personnel handling the meat are infected with bacteria that have developed resistance to most of the antibiotics used.