Pathogen enrichment device (PED) enables one-step growth, enrichment and separation of pathogen from food matrices for detection using bioanalytical platforms

The bottleneck for accurate detection of foodbome pathogens is separation of target analytes from complex food matrices. Currently used sample preparation methods are cumbersome, arduous and lengthy; thus, a user-friendly system is desirable. A hand-held sample preparation system designated pathogen enrichment device (FED) was built that contains a growth chamber, filters, and an ion exchange cartridge to deliver bacteria directly onto the detection platforms. Escherichia coli 0157:H7, Salmonella enterica and Listeria monocytogenes were used as model pathogens. Spinach, ground beef, hotdogs, and eggs were used as model foods to evaluate PED performance, and results were compared with traditional bag enrichment method. Bacterial cells were inoculated at 1, 10, and 100 CFU/g of the sample and enriched in PED using appropriate pathogen-specific selective enrichment broths. The bacterial cell counts in both PED and stomacher-bag were comparable and the pH in PED-recovered cell suspension was close to neutral whereas the pH of cell suspension in the stomacher-bag was slightly acidic. The bacterial recovery from the PED was 79-100% and was directly detected by lateral-flow immunoassay (LFIA), quantitative PCR (qPCR) and light scattering sensor with sample-to-result time of 8-24 h with a detection limit of 1 CFU/g. In qPCR, the amplified PCR products appeared in 4-5 cycles earlier with PED-enriched cultures compared to the cultures enriched in stomacher-bag. The hand-held PED proved to be a one-step procedure for enrichment and recovery of homogenous particle-free bacterial cells for detection using immunological, molecular or biosensor-based platforms. (C) 2015 Elsevier B.V. All rights reserved.