Cleaning and handling implements as potential reservoirs for bacterial contamination of some ready-to-eat foods in retail delicatessen environments.
This study assessed the association of bacteria with cleaning tools, such as floor mops (n = 25) and cleaning cloths (n = 39), and handling devices, such as disposable plastic gloves (n = 20), used during filled baguette and assorted salad preparation in four selected retail delicatessens in Johannesburg, South Africa. Samples of each cleaning or handling tool were prepared for aerobic (APC), coliform (CC), Escherichia coli (EC), Bacillus cereus (BCC), and Staphylococcus aureus (SAC) counts, as well as tested for the incidence of Listeria monocytogenes (LM) and Salmonella (SALM) by standard plating methods. Bacterial populations attached to the cleaning and handling tools were observed by scanning electron microscopy (SEM). Ten selected gram-positive isolates were further analyzed by 16S rRNA sequence analysis and compared with isolates from filled baguettes and assorted salads. The floor mops consistently yielded the highest APCs, CCs, and ECs (5.7, 4.1, and 3.0 log CFU/g, respectively), while gloves had the lowest corresponding counts (3.6, 2.0, and 1.0 log CFU/g, respectively). Low BCCs and SACs were recorded in this study (ca. 1.2 log CFU/g), while SALM and LM were each detected in five cleaning tool samples. SEM showed rods and cocci attached to handling and cleaning tools. Furthermore, results of 16S rRNA sequence analysis indicated that several gram-positive isolates were identified as S. aureus, Staphylococcus pasteuri, Staphylococcus sciuri, and Enterococcus faecalis. Genetically similar strains (100% similarity) were isolated from cleaning and handling tools and associated ready-to-eat (RTE) foods. Cleaning and handling tools may act as reservoirs of contamination for RTE foods during preparation in retail delicatessens in South Africa. The transfer of potential pathogens, such as S. aureus, to foods from cleaning and handling tools may hold food safety implications.
Christison
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CA
School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.
Lindsay
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von Holy
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D001419:Bacteria / Q000254:growth & development*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D003428:Cross Infection; D004197:Disease Reservoirs; D004866:Equipment Contamination; D005504:Food Analysis; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005522:Food Services / Q000592:standards*; D017575:Gloves, Protective / Q000382:microbiology; D006801:Humans; D006920:Hygiene; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013019:South Africa; D013045:Species Specificity
D012336:RNA, Ribosomal, 16S