P3-109 Reduced Time to Detection of Alicyclobacillus acidoterrestris in Fruit Juice Concentrates Using the Pall GeneDisc® Rapid Microbiology System

Wednesday, August 6, 2014
Exhibit Hall D (Indiana Convention Center)
Christopher McNamara, Ocean Spray Cranberries, Inc., Lakeville-Middleboro, MA
Danielle Wedral, Pall Corporation, Port Washington, NY
Patrick Zoder, Pall Corporation, Menlo Park, CA
Cally Toong, Ocean Spray Cranberries, Inc., Lakeville-Middleboro, MA
Margarita Gomez, Ocean Spray Cranberries, Inc., Lakeville-Middleboro, MA
Introduction: Alicyclobacillus acidoterrestris is an acidophilic, thermophilic, gram-positive bacterium that causes spoilage of fruit juices due to endospore survival of pasteurization.  Ingredient risk assessment is part of an overall strategy to prevent A. acidoterrestris spoilage.  However, traditional culture-based methods may take over a week, causing production delays, product holds or supply chain disruptions.

Purpose: This study compared the time needed to detect A. acidoterrestris spores in juice concentrates using culture-based methods and the GeneDisc System—a real time, quantitative, PCR-based system.

Methods: Apple and orange juice concentrates were inoculated in triplicate with A. acidoterrestris spores at 0.5 spores/ml and 0.1 spores/ml.  Concentrates were diluted 1:10 with water (apple) or YSG broth (orange) and heat shocked at 80°C for 10 min.  Orange juice was incubated at 43°C and sampled daily.  Apple juice was filtered through a 0.45 µm pore-size filter.  The filter was placed in 10 ml YSG broth, incubated at 43°C and sampled daily.  For analysis by culturing, samples were plated on YSG agar and incubated at 43°C.  For analysis, DNA was extracted from samples and amplified per the system protocol.

Results: Samples spiked with 0.5 spores/ml were detected positive by the system after a 24-hour enrichment.  Cycle threshold (Ct) values were 13.43 ± 0.96 for apple juice and 27.67 ± 3.45 for orange juice (mean ± sd).  Using culturing, A. acidoterrestris was not detectable until at least 48 hrs.  Samples spiked with 0.1 spores/ml were detected positive by the system after a 48-hour enrichment.  Ct values were 15.50 ± 1.23 for apple juice and 31.27 ± 6.15 for orange juice.  Detection by culturing required 48 hrs for apple juice and up to 5 days for orange juice.

Significance: The system can substantially reduce the time needed to detect A. acidoterrestris contamination of fruit juice concentrates.