V.O. and Isola T.O’s research while affiliated with University of Ibadan and other places

Adhesion of bacteria to meat processing surfaces may act as potential sources of transmission of pathogens in meat industry. Several studies have shown that adhesion of bacteria to surfaces partly depends upon the nature of the inert surfaces and partly upon the bacterial surface properties. The aim of this study was to compare the adhesion of E. coli and E. coli O157: H7 on wood, glass and steel surfaces. Twenty abattoir isolates of E. coli (8) and E. coli O157:H7 (12) from meat tables in Ibadan municipal abattoir, Nigeria were assayed for bacterial adhesion. Bacterial adhesion was assessed on wood, glass and steel surfaces at ambient temperature for 24 and 72 h. Attachment to surfaces was quantified using a crystal violet binding assay. In this study, E. coli isolates adhered on all the three surfaces studied, viz. wood, glass and steel. The isolates varied in their ability to adhere to the surfaces. The adhesion by isolates at 24 and 72 h were significantly different (p<0.05). The mean absorbance values (nm) at 24 h showed that E. coli O157:H7 (SEH1) adhere more bacterial cells on wood (0.51±0.02), steel (0.15±0.00) and glass (0.12±0.01) surfaces than E. coli (SE) which was wood (0.38±0.02), steel (0.13±0.01) and glass (0.07±0.01). At 24 and 72 h, a significant difference (p<0.05) was observed between the isolates for wood and glass. However, at 24 h, a significant difference (p<0.01) ensued between E. coli 0157:H7 and E. coli for steel. E. coli and E. coli 0157:H7 adhere more bacterial cells on wood than on steel and glass. Bacterial adhesion is influenced by strains with high virulence factors and an extension of incubating period. Proper surface selection can reduce the ability of bacteria adhesion on meat contact surfaces.

Antibiotics sensitivity test was assayed on thirty (30) isolates (10 each for Escherichia coli, Listeria and Salmonella) from retail meat (beef) tables in Ibadan municipal abattoir, Nigeria. The isolates were tested for sensitivity for eight (Listeria) and ten (Escherichia coli and Salmonella) commonly used antibiotics using Bauer-Kirby disc diffusion assay. Antibiotics sensitivity profile expressed in mean zone of inhibition (mm) ± standard error of mean showed that all the isolates were resistant to three or more antibiotics. All the isolates were resistant to tetracycline. The incidence of antibiotic resistance in virulent strains: E. coli O157:H7 (60%) and Salmonella typhi (60%) was higher than the non virulent strains: E. coli (40%) and Salmonella spp, (50%), respectively. The overall incidence of antibiotics resistance in Listeria strains was relatively lower (37.5%) than the other pathogens. The high rate of resistance revealed abuse of antibiotic usage in cattle. The public health significance of these findings is that the resistant strains from meat tables may find their way into human population through food chain and occupational exposure.