Premium
Evaluating the Extraction Efficiency of Food Borne Pathogens on Automated Homogenizer Platforms
Author(s) -
Garrett Shari,
Atwood James,
Easparro Brandon
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1082.3
Subject(s) - homogenizer , food science , food processing , sample preparation , food products , analyte , food safety , food microbiology , pulp and paper industry , microbiology and biotechnology , environmental science , biology , chromatography , chemistry , bacteria , genetics , engineering
There is an ever increasing demand for food and beverage manufacturers to adhere to rigorous food safety regulations. As part of the global need for safe food, food and beverage manufacturers test their products for the presence of food borne pathogens. While safety regulations describe what pathogens should be controlled through testing there is no predefined method of sample preparation or detection. Typically, the first step in a food borne pathogen detection study is the disaggregation of the food product or the washing of the sample to release bacteria from the food surface using a Stomacher. While the later method is great for large masses of food stuffs, some researchers may require small amounts of product for analysis. Bead mill homogenizers, as well as rotor‐stator homogenizers, can be used to aid in the sample preparation process. Processing can be completed in less than one minute while maintaining bacterial cell and analyte integrity. Depending on the pathogen of interest and the food matrix, the downstream results, including sensitivity can vary greatly based on the sample preparation method chosen. With this is mind, we analyzed two sample preparation techniques on commonly contaminated foods. Meat and spinach samples were inoculated with known levels of recombinant E.coli expressing Green Fluorescent Protein. The inoculated samples were processed on a bead mill homogenizer and an automated rotor‐stator homogenizer. The homogenates were grown on nutrient agar and the proportion of viable cell recovery was quantified. Limit of detections were determined by lysis of recovered homogenates, DNA purification and PCR amplification. It was determined that both homogenization techniques were able to process food samples for the extraction of live cells and plasmid DNA. The processing efficiency can deliver a 76% cell recovery with a PCR detection limit to 1×10 −5 CFUs/ml. A linear relationship was demonstrated between the number of CFUs to intensity of DNA amplified via PCR. A detection limit of 10 −5 CFUs is comparable to some food testing methods; however the vigorous processing of bead mill and rotor stator technology has the potential to eliminate the standard pre‐enrichment step needed for the detection of food pathogens.