Purpose: A novel oxygen depletion technology, GreenLight, has seen increasing use as a screening tool for fresh food. This technology uses the oxygen respiration of viable aerobic organisms to rapidly estimate the Total Plate Count (Total Viable Count) of food samples. An automated system was used in a plant trial in Slovakia over a period of 4 months, to measure and improve the incoming quality of raw pork meat, as measured by TPC.
Methods: The study assessed incoming lots of pork meat from up to 5 suppliers, using the rapid system calibrated for results in CFU/g. Each sample was weighed and diluted following the preparation guidelines for ISO4833:2013. However, no serial dilutions or fixed incubation periods were required. Results for the overall period were tabulated to determine average counts, pass/fail and supplier trends.
Results: One hundred twenty-two (122) pork samples were tested over 4 months. The producer selected an automatic “fail” level of 1 million CFU/g (6 log CFU/g). In the evaluation period, 13 samples failed these criteria (10.7%). The mean result from the rapid system was 5.2 log CFU/g. Failed samples were identified by unique bar codes. The technology returned lower test times the higher the microbial load; therefore it was possible to predict a maximum assay period by which 99.9% of samples would show a countable result. This was found to be 8 hours.
Significance: The study predicts that this meat producer can identify TPC results within 8 hours, allowing rejection of incoming materials, identifying offending suppliers and rewarding compliant suppliers.