Rapid detection of microbial contamination in UHT milk: practical application in dairy industry

Abstract

Microbial quality of ultra-high temperature (UHT) milk is usually ascertained by a total bacterial count (TBC) cultivation. But this is time consuming, so there is a tendency to search for faster and simpler methods. We compared three instruments, focusing on shortening the detection time and their suitability for practical use in dairy plants. Two of them, RapiScreen Dairy 1000 and Promilite III, detect microbial contamination by measuring adenosine triphosphate bioluminescence; the third, GreenLight, is based on oxygen consumption analysis. In the laboratory experiments, samples of UHT milk, were spiked with low concentration of microorganisms and then the level of microbial contamination was evaluated using the above-mentioned instruments together with cultivation method as a control. The instruments were also applied in a dairy plant to test 182 real samples. All investigated methods determined microbial quality faster than the TBC, but in some cases false positive and false negative results were obtained. Therefore, precise testing including optimizing pre-incubation time for bacteria enrichment is needed prior to industrial use.

Application of Biosensors for Detection of Pathogenic Food Bacteria: A Review

“…Other studies have examined the use of the bioluminescence -based ATP technique compared to total bacterial count (TBC) cultivation for rapid microbial identification to monitor ultra-high temperature (UHT) milk quality [186]. ATP bioluminescence was suitable for detecting very low concentrations of microbial content compared to results for conventional total bacterial counts, and the analysis time was only 20 min.…”

Immobilization of Firefly Bioluminescent System: Development and Application of Reagents

“…The FLuc-based biosensors have the widest application in the food industry to determine the degree of bacterial contamination of foodstuff and beverages and, thus, assess their quality [3]. Methods have been worked out to assess the quality of milk [4][5][6], beer [7][8][9], drinking water [10,11], and meat [12]. A somatic cell count assay has been proposed as a diagnostic indicator of cow mastitis [13].…”