Preventing Salmonella on Tomatoes Using Peroxyacetic Acid in Water Systems

Jim Crocker
30th May, 2024

Preventing Salmonella on Tomatoes Using Peroxyacetic Acid in Water Systems

Image Source: Natural Science News, 2024

Key Findings

  • The University of Florida study found that peroxyacetic acid (PAA) can prevent Salmonella cross-contamination in tomato flume tanks
  • Higher organic loads reduce the stability of PAA, making it less effective
  • PAA concentrations as low as 5 mg/L can prevent cross-contamination at low contamination levels if no organic load is present
Tomato processing often involves using flume tanks, which can be a source of cross-contamination and potentially lead to foodborne illnesses. A recent study conducted by the University of Florida aimed to evaluate the effectiveness of peroxyacetic acid (PAA) at concentrations of up to 80 mg/L in preventing Salmonella enterica cross-contamination in a controlled flume tank environment[1]. The research focused on how PAA performs under different levels of organic load, measured as chemical oxygen demand (COD). Organic load is significant because it can affect the stability and efficacy of sanitizers. The study used tomatoes inoculated with a high level (108 CFU/tomato) and a lower level (106 CFU/tomato) of a rifampin-resistant Salmonella cocktail. Both inoculated and uninoculated tomatoes were introduced into the flume tank containing varying concentrations of PAA (0-80 mg/L) and organic load (0 or 300 mg/L COD). The study found that higher organic loads significantly reduced the stability of PAA, causing it to break down faster. When the tomatoes were contaminated at the higher level (108 CFU/tomato), cross-contamination occurred even with 80 mg/L of PAA, irrespective of the organic load. However, for tomatoes contaminated at the lower level (106 CFU/tomato), PAA concentrations as low as 5 mg/L were effective in preventing cross-contamination when no organic load was present. At 300 mg/L COD, 100% of the tomatoes showed cross-contamination at 5 mg/L PAA. Increasing the PAA concentration to 10 mg/L effectively prevented cross-contamination, regardless of the organic load. These findings suggest that PAA can be an effective sanitizer for preventing bacterial cross-contamination in tomato flume tanks, especially at concentrations lower than the maximum limit. This offers a more environmentally friendly option for tomato packinghouse operators. Previous studies have explored the efficacy of various sanitizers in similar settings. For instance, research on fresh-cut lettuce showed that chlorine and Tsunami were effective in reducing E. coli in processing water and preventing cross-contamination between contaminated and uncontaminated produce[2]. Similarly, another study assessed the effectiveness of hypochlorous acid (HOCl) in a model flume system for tomatoes, finding that 25 ppm of HOCl was adequate to prevent Salmonella cross-contamination under certain conditions[3]. Further research indicated that 100 ppm of HOCl was necessary to prevent cross-contamination in the presence of high organic load[4]. The current study expands on these earlier findings by focusing on PAA as an alternative sanitizer. It highlights the importance of maintaining appropriate sanitizer levels and managing organic load to ensure the effectiveness of the sanitizing agents. The results align with previous research that emphasizes the need for proper monitoring and maintenance of water quality in flume tanks to prevent pathogen cross-contamination during postharvest washing of tomatoes[5]. In summary, the University of Florida study demonstrates that PAA, even at lower concentrations, can effectively prevent Salmonella cross-contamination in tomato flume tanks, provided that the organic load is managed. This makes PAA a viable and environmentally friendly option for tomato packinghouse operations, contributing to safer food processing practices.



Main Study

1) Evaluating the efficacy of peroxyacetic acid in preventing Salmonella cross-contamination on tomatoes in a model flume system.

Published 30th May, 2024

Related Studies

2) Prevention of Escherichia coli cross-contamination by different commercial sanitizers during washing of fresh-cut lettuce.

3) Control of Salmonella Cross-Contamination between Green Round Tomatoes in a Model Flume System.

4) Determination of Optimum Sanitizer Levels for Prevention of Salmonella Cross-Contamination of Mature Round Tomatoes in a Laboratory Model Flume System.

5) Determining Bacterial Load and Water Quality Parameters of Chlorinated Tomato Flume Tanks in Florida Packinghouses.

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