Bacteriological quality of indoor air environment in private and government owned abattoirs in benin city, nigeria

The airborne bacterial load of two abattoirs, private and government abattoirs in Benin City was studied using the settled plate methods. The air samples were collected during and after slaughtering operations in the two abattoirs monthly for a period of six months, between October, 2011 and March, 2012. The temperature and relative humidity of the two abattoirs were determined during each sampling time. The plasmid DNA profile of the isolated airborne bacterial was determined using the alkaline lysis method. The temperature reading ranged between 25 0C and 34 0C in the private abattoir and between 26 0C and 35 0C in the government abattoir. The relative humidity reading ranged between 46 % and 67 % in the private abattoir and between 34 % and 65 % in the government abattoir. The mean airborne bacterial counts on nutrient agar and blood agar in the private abattoir ranged from 17.55 x 102 ± 3.77cfu/m3 to 108.0 x 102 ± 10.35cfu/m3 during slaughtering and 12.84 x 102 ± 1.51 cfu/m3 to 49.71 x 102 ± 3.61 cfu/m3 after slaughtering. The mean airborne bacterial counts on nutrient agar and blood agar in the government abattoir ranged from 24.63 x 102 ± 3.75cfu/m3 to 58.30 x 102 ± 6.49 cfu/m3 during slaughtering and 15.62 x 102 ± 2.97 cfu/m3 to 114.13 x 102 ± 19.75 cfu/m3 after slaughtering. The mean airborne bacterial counts grown on eosine methylene blue agar in the private abattoir ranged from 1.057 x 102 ± 2.58 cfu/m3 to 22.54 x 102 ± 5.70 cfu/m3 during slaughtering and 2.44 x 102 ± 1.41 cfu/m3 to 9.87 x 102 ± 1.41 cfu/m3 after slaughtering. The mean airborne bacterial counts grown on eosine methylene blue agar in the government abattoir ranged from 1.05 x 102 ± 5.62 cfu/m3 to 24.40 x 102 ± 4.66 cfu/m3 during slaughtering and 1.06 x 102 ± 4.24 cfu/m3 to 21.08 x 102 ± 3.94 cfu/m3 after slaughtering. The result revealed the isolation of seven airborne bacterial isolates which include Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus sp., Bacillus sp., Pseudomonas sp., Klebsiella sp., and Escherichia coli. The frequency of occurrence and distribution of the airborne bacterial isolates revealed Staphylococcus. aureus (48.75%) and Bacillus sp. (28.68%) as the most frequently isolated airborne bacterial isolates in the private abattoir, while S. aureus (31.95%) and Bacillus sp. (41.93%) were also recorded as the most frequently isolated airborne bacterial isolates in the government abattoir. The statistical analysis showed no significant difference between the airborne bacterial counts recorded during and after slaughtering in the two abattoirs. The result of the plasmid determination revealed that the airborne bacterial isolates harboured plasmid sizes which ranged between 1.5 kbs to 25.2 kbs. The result revealed that, the quality of air in the abattoirs was greatly influenced by the population and type of airborne bacterial isolates, which play significant role in the level of hygiene in meat processing plants. The type and population of airborne bacterial isolates in the indoor air of the two abattoirs are of great concern, which serves as index of quality of air in the environment. Hence, great measures are taken to checkmate this menace caused by the poor hygienic systems in the abattoirs