Novel spider web trap approach based on chitosan/cellulose nanocrystals/glycerol membrane for the detection of Escherichia coli O157:H7 on food surfaces.

The aim of this study was to develop a novel approach allowing simultaneous enrichment as well as specific and fast detection of Escherichia coli O157:H7 by indirect ELISA using optimized support membrane based on chitosan (CHI), cellulose nanocrystals (CNCs), and glycerol (GLY). Therefore, combining the step of the capture of the pathogen and enrichment steps for the microbial growth led to a high detection signal at a low inoculation level without cross-reaction with Pseudomonas and Salmonella strains. The detection was performed by varying incubation periods and different level of inoculations. The signal of detection in samples incubated with the chitosan-based support reinforced with CNCs and directly from E. coli O157:H7 bacterial culture was much higher as compared to CNCs-free support with cell-free supernatant samples. The CCG support reinforced with 0.6% CNCs improved the detection signal of E. coli O157:H7 by 25% compared to control. The whole bacterial culture showed a higher immobilization signal than unfiltered and cell-free supernatant. The spider web trap approach (SWTA) detect E. coli O157:H7 after only 4 h of enrichment compared to 24 h with conventional methods. The adjustment of this innovative SWTA could minimize the risks of cross-contamination and consequently, food product recalls by facilitating significantly the detection of foodborne pathogens in samples collected from food surface, tools and work surfaces in food processing industries.

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