Skip to main content
ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Microbial and Chemical Food Safety » Research » Publications at this Location » Publication #411153
Research Project: Integration and Validation of Alternative and Multiple Intervention Technologies to Enhance Microbial Safety, Quality, and Shelf-life of Food

Location: Microbial and Chemical Food Safety

Title: Effects of biotic and abiotic factors on attachment and survival of Salmonella Typhimurium on post-harvest produce

Author
item Olanya, Modesto
item Ukuku, Dike
item Niemira, Brendan
item Mukhopadhyay, Sudarsan

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Salmonella contamination of post-harvest produce is a persistent problem worldwide. Determination of factors that influence and adversely mitigate Salmonella attachment and its survival is essential for limiting contamination and enhancing pathogen reductions on produce. Post-harvest carrots, alfalfa sprouts, soybeans and pistachio were inoculated with 6-7 log CFU/g of S. Typhimurium by dipping each produce in 20mL of bacterial suspension in sterile stomacher bags. Storage temperature (5 and 25C) effects on Salmonella attachment (SR-values) were quantified after inoculations. Treatment of pathogen-inoculated produce with a biosurfactant (lauric acid amide pyrrolidine, LAPY), bacterial competitor (Bacillus subtilis), and physical decontamination with peptone water (PW) rinses on Salmonella attachment and survival were determined. SEM imaging was done to compare Salmonella attachment on produce before and after treatments. Pathogen populations were quantified by plating aliquots (100µL) from rinses and stomaching produce in PW and plating dilutions on XLT-4 selective medium (37C). Data on Salmonella populations were converted to Log CFU/g and were analyzed with analysis of variance (ANOVA) to assess significance of treatment effects by statistical analysis system (SAS Institute, Cary, NC). Storage temperatures influenced the strength of Salmonella attachment for produce types as SR-values were significantly (p<0.05) greater on pistachio and soybean (0.53-0.76) than alfalfa and carrots (0.10-0.13). LAPY application resulted in greater pathogen reductions on alfalfa, pistachio and soybean (2.1-3.0 logs), but not on carrot (<1.5 log). The presence of the bacterial competitor (B. subtilis), in combination with S. Typhimurium, resulted in non-significant reductions in pathogen attachment, except on alfalfa sprouts. Physical decontamination of pathogen-inoculated produce by PW rinse significantly (P<0.05) reduced bacterial attachment and Salmonella populations on produce. These results indicate that mitigation of Salmonella attachment by selective application of post-harvest decontamination measures may limit pathogen survival and enhance the safety of post-harvest produce.