Location: Food Safety and Intervention Technologies ResearchTitle: Fate of injured Salmonella and Escherichia coli 0157:H7 on Granny Smith apples after cold plasma and organic acids treatments
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/10/2019
Publication Date: N/A
Technical Abstract: Introduction. Inability of chlorine base antimicrobial treatments to kill all bacterial populations on fruit surfaces designated for fresh-cut preparation is a food safety problem. There is a need for an alternative sanitizer treatment that can achieve a better inactivation without damaging the surface characteristic and the atheistic appeal of the treated fruits. Purpose. To estimate percent population of injured bacterial pathogens after cold plasma treatments at 40s and how these injured populations will react upon further treatments with short chain organic acids. Methods. Granny Smith apples were inoculated with 107 CFU/ml Salmonella and Escherichia coli O157:H7 inoculum, respectively. All inoculated apples were exposed to cold plasma treatment for 40s, followed immediately by dipping in solution of organic acids for 5 min. Bacterial populations on apple surfaces before and after treatments were enumerated using selective and non-selective agar media. Injured populations by cold plasma treatments was assayed before and after organic acids exposure. Results. After inoculation of the apples, bacterial pathogens recovered on the apples averaged 4.6±0.18 log CFU/ g and 4.8±0.14 log CFU/g for Salmonella and Escherichia coli O157:H7, respectively. Cold plasma treatments for 40s led to average 0.5 log inactivation for the pathogens and the percent injured bacteria among the survivors averaged 18 and 20 % for Salmonella and Escherichia coli O157:H7, respectively. Cold plasma treatments followed immediately by dipping apples in organic acids solutions for 5 min led to 3.8 log inactivation, and the injured populations was < 1%. Significance. These results suggest that the injured pathogen on apple surfaces treated with cold plasma can be totally inactivated by immediate treatment with organic acid solution suggesting that this treatments procedure will enhance the microbial safety of treated apples designated for fresh-cut preparation.