The purpose of this paper is to evaluate the frequency and antimicrobial susceptibility pattern of pathogens present in ready-to-eat salads available at a local market.
A 100 salad samples were collected aseptically. Each sample (25 g) was homogenized in 225 ml of sterile peptone water and was serially diluted up to 1×106. Dilutions were inoculated on nutrient agar by surface spread plate technique. Aerobic colony count (ACC) was estimated by counting the colonies. Bacterial isolates were cultured on blood and MacConkey agar and identified on the basis of their morphology, culture characteristics and confirmed by API 20E and 20NE. Antimicrobial susceptibility was determined as per CLSI 2014.
ACC range was 1.1×103 cfu/g to 5.8×109 cfu/g. Among these the highest ACC was found in channa chat (4.9×104 to 5.8×109 cfu/g). A total of 127 microorganisms were identified; 73 were gram negative rods (GNRs) and 24 were gram positive cocci (GPC). Among GNRs; Klebsiella spp. (n=18) was the predominant whereas among GPC, Staphylococcus aureus (n=6) were the chief pathogen. Klebsiella spp. showed 100 percent resistance to ampicillin, 89-78 percent to amoxicillin/clavulanic acid and 33 percent to imipenem, however, Enterobacter spp. were resistant to ampicillin (100 percent) amoxicillin/clavulanic acid (77 percent) and imipenem (23 percent). Staphylococcus aureus showed resistance to co-amoxiclav (83 percent) and penicillin (75 percent).
This study revealed that effective control measures must been implemented and respected by throughout the entire food chain and better surveillance studies should be performed at national level to reduce the spread of bacteria by fresh salads.
This paper explore the high prevalence of multidrug-resistant pathogens in different salads and most of the salads were found to be unhygienic for consumption.
The authors would like to thank all the owners of the restaurants and venders for providing the salad samples.
Ilyas, S., Qamar, M.U., Rasool, M.H., Abdulhaq, N. and Nawaz, Z. (2016), "Multidrug-resistant pathogens isolated from ready-to-eat salads available at a local market in Pakistan", British Food Journal, Vol. 118 No. 8, pp. 2068-2075. https://doi.org/10.1108/BFJ-02-2016-0058
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