Short communication Assessment of carcass contamination with E. coli O157 before and after washing with water at abattoirs in Nigeria M. Bello a, ⁎, M.K. Lawan a , J.K.P. Kwaga a , M.A. Raji b a Department of Veterinary Public Health and Preventive Medicine, Ahmadu Bello University, Zaria, Nigeria b Department of Veterinary Pathology and Microbiology, Ahmadu Bello University, Zaria, Nigeria abstract article info Article history: Received 8 April 2011 Received in revised form 29 June 2011 Accepted 23 July 2011 Available online 29 July 2011 Keywords: E. coli Water Carcass contamination Abattoir The study was carried out to assess the level of beef carcass contamination with Escherichia coli including O157 strains before and after washing with water. Samples of water used for washing carcasses were collected and thirty beef carcasses were swabbed within a period of one month in each of three abattoirs located in North-Western states of Nigeria. E. coli were enumerated as indicator organisms. Using conventional biochemical tests, the isolation rate of E. coli in the 120 swab samples collected in each abattoir from external and internal surfaces of the carcasses was 58.3% at Kano abattoir, 70.8% at Sokoto abattoir, while 76.7% was recorded at Zango abattoir. E. coli counts from external and internal surfaces of the carcasses were enumerated as mean log and ranged between 4.3 Log 10 and 4.6 Log 10 cfu/cm 2 before washing, while the values were 4.6 Log 10 and 4.9 Log 10 cfu/cm 2 after washing. Data analysis revealed that the increase in E. coli counts after washing carcasses with water was statistically significant (P b 0.05) in all the abattoirs. However, there was no statistically significant difference (P N 0.05) between the 3 abattoirs in mean log of E. coli counts from external surfaces of carcass after washing. E. coli O157 was identified from both the water and surfaces of carcasses using Latex agglutination kit. A prevalence of 2.8% of E. coli O157 was detected in 360 swab samples from 90 beef carcasses examined. E. coli counts from water used in washing carcasses were between 22 and 120 cfu/100 ml. Of the 72 water samples, 3(4.2%) were positive for E. coli O157. In conclusion, there was increased contamination of carcasses during processing and water used in washing carcasses might have contributed to carcass contamination in all the abattoirs studied due to use of non-potable water. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Meat safety in the 21st century remains a key issue of public health concern to both developing and the advanced countries particularly under the present concept of one world one health. In recent years, some outbreaks of foodborne diseases in the United States caused by pathogenic bacteria such as E. coli O157:H7 and Listeria monocytogenes, have brought about meat safety issues to the forefront of societal concerns (Sofos, 2008). An estimated 10% of the population suffers from foodborne illnesses annually in Europe (Motarjemi and Kaferstein, 1999). In Nigeria, foodborne illness in human beings due to bacterial pathogens is well documented (Umoh et al., 1990). Similarly, a review on the safety of animal food products safety situation in Nigeria by Okoli et al. (2006), highlighted the fact that the production, handling, sales, and consumption of poor quality animal food products are serious public health problems in the country. The major meat consumed in Nigeria is beef (Taiwo et al., 2006). Biological, chemical, and physical hazards are encountered in beef slaughtered and processed in the abattoir. The biological hazards are mainly bacterial pathogens such as E. coli O157:H7, Salmonella and Listeria spp (Declan et al., 2004). E. coli has been used as indicator of possible post-processing contamination and its presence as indicator of fecal contamination in foods (Hilal et al., 2003). A display process for raw meat can be assessed with respect to microbiological safety by estimation of the growth of E. coli (Greer et al., 1994). In beef carcass processing, E. coli associated with cattle carcasses can increase or decrease during processing depending on factors such as the levels of contamination of live cattle, efficiency of evisceration and hygienic practice in the abattoir (Rigobelo et al., 2006). Slaughter plants have also been required to test carcasses for generic E. coli as an indicator of the adequacy of the plant's ability to control fecal contamination (Anonymous, 1994). This study was designed to assess the level of carcass contamination before and after washing with water, using E. coli as indicator organism and to determine the prevalence of E. coli O157 in all the 360 swab samples. 2. Materials and methods The study was carried out in 3 states of northwestern geopolitical zone of Nigeria. The zone was conditionally, for the purpose of this work, divided into 3 sub-zones. This included Sub-zone A which International Journal of Food Microbiology 150 (2011) 184–186 ⁎ Corresponding author. Tel.: + 234 803 5375073. E-mail address: mbrobah@yahoo.com (M. Bello). 0168-1605/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.ijfoodmicro.2011.07.029 Contents lists available at ScienceDirect International Journal of Food Microbiology journal homepage: www.elsevier.com/locate/ijfoodmicro