|BERRIOS-RODREGUEZ, AMARYNETTE - University Of Puerto Rico|
|ORELLANA, LYNETTE - University Of Puerto Rico|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/31/2020
Publication Date: N/A
Technical Abstract: Introduction: Periodic occurrences of foodborne pathogens and contamination of minimally processed foods have been commonly reported. Among the foodborne pathogens, Escherichia coli O157:H7 and Salmonella enterica have been most frequently associated with food safety concerns. Purpose: Evaluate the efficacies of hurdle interventions consisting of low-dose radiation (R), sanitizer (S) and biocontrol (B) treatments on the survival of E. coli O157:H7 on post-harvest carrot and tomato at different storage times and temperatures. Methods: Low dose radiation (0.5 kGy), nisin-based sanitizer (low pH, 2 mL/g), and biocontrol microbe (non-pathogenic, Pseudomonas fluorescens, ~6 Logs) were applied on post-harvest carrot and tomato previously inoculated with cocktail of pathogenic E. coli O157:H7 strains relative to control. Two and three hurdle treatment effects on survival and reductions of pathogens were also assessed. Results: The survival of E. coli O157:H7 on post-harvest produce were significantly (P<0.05) reduced by treatments (membrane damage / competitive exclusion) and their combinations at different storage temperatures (5 and 20C) and times (0 and 7days). Mean reductions of E. coli O157:H7 on carrot and tomato by hurdle treatments ranged from 1.20-1.77 logs and 0.40-2.82 logs, at 5C, respectively. Similarly, E. coli reductions at 25C were 1.03-3.11 logs on carrot and 1.30-2.97 logs on tomato. Sanitizer had greater efficacies than radiation and biocontrol treatments. Significance: The survival of E. coli O157:H7 was significantly (P<0.05) impacted by sanitizer, radiation, and biocontrol treatment to a lesser extent. Hurdle applications had synergistic effects and its use can improve the microbiological safety of post-harvest carrot and tomato.