P2-24 Rapid Detection of Microbial Contamination in UHT Beverages Using Microbial Luminescent Technology

Tuesday, August 2, 2016
America's Center - St. Louis
Gabriela Lopez-Velasco, 3M Food Safety, St. Paul, MN
Sailaja Chandrapati, 3M Food Safety, Maplewood, MN
Neil Percy, 3M Food Safety, St. Paul, MN
Cristina Constantino, 3M Brazil, Sumare, Brazil
Introduction: Beverages processed with ultra-high temperature treatments (UHT) or extended shelf life (ESL) have increased demand in the food market. Microbial analysis for testing commercial sterility is traditionally done with agar plating after product enrichment, which can take several days to confirm a negative result delaying product release.

Purpose: To evaluate a novel universal rapid detection kit based on microbial ATP bioluminescence for screening commercial sterility compared to traditional methods including growth on agar and pH measurement.

Methods: A variety of twenty-one UHT or ESL beverages (n=2/beverage/microorganism tested) were inoculated with 10 to 100 CFU/container utilizing a panel of microorganisms including a combination of bacteria (gram positive, gram negative and lactic acid bacteria),  yeast and molds as applicable. A negative control (uninoculated blank) and positive control (inoculated with ~1,000 CFU) were also included in each matrix (N=1,104 total samples). Inoculated beverage containers were pre-enriched at 30°C for up 48 and 72 hours for dairy beverages and juices or juice dairy combinations, respectively. After enrichment beverages were screened for commercial sterility utilizing standard methods agar (SMA) as a reference method, pH and a novel universal Microbial Luminescence System based on the detection of microbial ATP.

Results: Utilization of microbial ATP bioluminescence resulted in a rapid method to screen commercial sterility in UHT beverages. Sensitivity and specificity were 98 and 99%, respectively, compared to agar. The study demonstrated that the novel universal kit can detect the presence of microbial contamination > 48 hours sooner than the traditional agar method. The study also demonstrated that pH is not a reliable parameter to screen for commercial sterility as not all microorganism will modify the pH during pre-enrichment.

Significance: Microbial ATP bioluminescence can provide a rapid result to screen commercial sterility by significantly reducing time to product release and thus reducing inventory hold times.