Sub-objective 4.1. Determine efficacy of postharvest sanitizers used in dump tank or flume systems for bacterial and viral foodborne pathogens, considering industry use and management practices.

Methods:

• Evaluation of chlorine and peroxyacetic acid for efficacy in model postharvest washing systems with varying organic load.
• Assess inactivation on inoculated stone fruit, cucumbers, and leafy greens during washing, transfer to the water and subsequent cross-contamination to uninoculated crop using Salmonella, L. monocytogenes, and a non-pathogenic bacterial surrogate.

Expected outcomes:

• Validation of minimum antimicrobial concentrations required to prevent cross-contamination using treatment conditions reflective of industry practices.
• Concentrations of each sanitizer needed for inactivation of pathogens will provide data which packinghouses can utilize to develop robust water management systems as part of their food safety plan validation.

Sub-objective 4.2. Determine critical parameters for effective sanitation of food contact surfaces most commonly associated with prevalence of foodborne pathogens and their indicators or where knowledge gaps exist.

Methods:

• Targeting of surfaces commonly used for packing crops (e.g. plastic and wooden bins, harvest totes, PVC rollers, high density polyethylene (HDPE), foam covered PVC rollers, brushes used for washing and waxing) which reflect areas with a greater incidence of foodborne pathogen niches.
• Evaluation of transfer from surfaces encountered during harvest to food contact surfaces and subsequently to model crops.
• Use of five-strain cocktail of L. monocytogenes or Salmonella and a non-pathogenic E. coli surrogate across all sites.
• Assessment of efficacy of cleaning and sanitation approaches for inoculated surfaces through three primary methods:
  1) clean with foam detergent, allow to sit for 1 min, rinse with distilled, deionized water and expose to the sanitizer
  2) rinse with distilled water and expose to the sanitizer
  3) expose to the sanitizer

Expected outcomes:

• Capture the risk tied to cross-contamination of various food contact surfaces encountered from harvest through packing.
• Determine efficacy of common sanitation approaches for inactivating L. monocytogenes or Salmonella on complex surfaces more commonly associated with bacterial niches.
• Provide packinghouse operators with science-based knowledge which can be incorporated to their standard sanitation operating procedures to effectively remove and/or inactivate transient bacteria which may be introduced during packing.