Prevalence and loads of fecal pollution indicators and antibiotic resistance of Escherichia coli in raw minced beef in Lebanon.

Abstract

Meat is an important source of high biological value proteins as well as many vitamins and minerals. Meat production has been increasing rapidly over the years. In Lebanon, beef meat is the most consumed out of the meat products. In 2014, the average consumption in Lebanon was 39.63 kg-capita. Contaminated beef meat can be an important source of bacterial pathogens, which cause severe foodborne illnesses. However, data on the contamination of beef meat is scarce in Lebanon. This is important, because beef meat is also consumed raw in Lebanon. Raw minced beef meat was selected for this study, because mincing can increase the risk of contamination and this matrix is used in a variety of Lebanese recipes. The overall aim of this research was to provide an assessment of microbiological quality of raw minced beef in Lebanon. The specific objectives of this study were to determine and quantify the prevalence and loads of fecal coliforms and Escherichia coli in raw minced beef in Lebanon. In addition, the antimicrobial resistance profiles of E. coli isolated from the raw minced beef were also determined. A total of 50 raw minced beef samples were obtained from butcheries and grocery stores in Beirut city. For each sample, 25 grams of raw minced beef was placed in a stomacher bag with 225 ml of sterile buffered peptone water. The bag was homogenized for up to 60 seconds in a stomacher. Serial 10-fold dilutions were prepared (10-1, 10-2, 10-4) using sterile peptone buffered water. The dilutions were spread onto RAPID’ E .coli 2 Agar plates, which were then incubated for 18 to 24 hours under aerobic conditions. After incubation, colonies that matched diagnostic phenotypes for fecal coliforms and E. coli were counted per gram of raw minced beef. The fecal coliforms counts were compared to LIBNOR standards, while the E. coli counts were compared to standards from other countries. From the samples, 120 E. coli isolates were retrieved and analyzed for antimicrobial susceptibility using the Kirby Bauer disk diffusi