Location: Produce Safety and Microbiology ResearchTitle: Reduction of Listeria monocytogenes and Salmonella Typhimurium on blueberries through brief-exposure to antimicrobial solutions coupled with freezing Author
|Tadepalli, Shravani - University Of Maine|
|Anderson, Ryan - University Of Maine|
|Zhang, Rong - University Of Maine|
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2019
Publication Date: N/A
Interpretive Summary: Blueberries are susceptible to microbial contamination and to reduce foodborne illnesses associated with blueberries, it is important to utilize effective decontamination methods. This study evaluated the efficacy of brief-exposure to different antimicrobial washes (chlorine (Cl2), chlorine dioxide (ClO2), ozone (O3), and lactic acid) when coupled with frozen storage, (-12°C for 1 week) in inactivating foodborne pathogens (Salmonella Typhimurium and Listeria monocytogenes) on blueberries. The results indicated that the combination of antimicrobial treatment and frozen storage was more effective in reducing pathogens than wash treatments alone. This protocol can be incorporated in suitable processing procedures in the food industry to prevent pathogen contamination.
Technical Abstract: This study evaluated the efficacy of different brief-exposure antibacterial washes (= 3 min) coupled with frozen storage against Listeria monocytogenes and Salmonella Typhimurium on blueberries. Inoculated berries where treated with chlorine (200 ppm), chlorine dioxide (15 ppm), ozone (3 and 5 ppm), and lactic acid (2%) for short exposure times (10 s, 1 min, or 3 min) and antibacterial effectiveness was determined with or without an additional freezing hurdle (-12 ºC; 1 week). Wash treatments alone resulted maximum log reductions from 1.0-2.8 while the additional freezing step increased this range to 3.7-6.6. The greatest reduction of L. monocytogenes (6.6 log) and S. Typhimurium (5.3 log) was observed after freezing combined with 3 min exposure to 2% lactic acid or 15 ppm ClO2 respectfully. After treatment there was no residue measured by utilized methodologies. However, lactic acid treatment resulted in a change of aroma. In conclusion, wash treatments of blueberries utilizing short exposure times maintained antimicrobial effectiveness and can be further enhanced by coupling with freezing.