Evaluation of sanitation protocols for nonconventional food-contact surface materials used in produce packinghouses

Evaluation of sanitation protocols for nonconventional food-contact surface materials used in produce packinghouses

Jan. 1, 2024 - Dec. 31, 2025

2024CPS03

University of Arkansas

$206,108.00

Kristen Gibson, Ph.D.
University of Arkansas

There is a lack of guidance in the produce industry on cleaning and sanitizing porous food-contact surfaces in packinghouse environments. Current practices need to be validated to assess any associated microbial risks, and future guidance should be data-driven prior to implementation. This proposal focuses on evaluating cleaning and sanitizing practices for porous food-contact surfaces in packinghouses across the U.S., and the associated risks of product contamination influenced by surface/equipment characteristics in these environments. Semi-structured Interviews with growers at very small to medium operations as well as Extension Specialists across the U.S. working with produce growers will aid in characterizing the most common porous food-contact surfaces and current cleaning and sanitizing practices. The experimental approach in the laboratory will be informed by these interviews. First, the persistence and potential growth of microorganisms on six porous food-contact surfaces subjected to a variety of conditions relevant to produce production environments will be assessed. This work will be followed by evaluation of cleaning and sanitizing protocols for each of the six porous food-contact surfaces. The data generated from this research will help characterize the risks associated with porous food-contact surfaces and limit cross contamination during packing operations.

Technical Abstract

Limited knowledge is available in the peer-reviewed literature on cleaning and sanitizing (C&S) efficacy of unconventional, often porous, food-contact surfaces (FCS) in produce packinghouse environments. Based on discussions with the produce industry and produce safety extension specialists, C&S of packinghouse surfaces ‘as needed’ is subjective and largely based on visual inspection and convenience. There is a lack of guidance for C&S best practices on porous FCS in produce packing areas, and there is a need for evidence-based Sanitation Standard Operating Procedures (SSOP). This research will determine the effectiveness of C&S practices for common porous FCS found in the produce industry, specifically growers with medium, small, very small, and limited season operations. In the proposed work, a mixed methods approach will be used to verify porous FCS selection and parameters for evaluation. Specifically, semi-structured interviews will be conducted with 15 to 20 growers from medium, small, very small, or seasonally limited operations within Arkansas and the northeast U.S. These interviews will be transcribed followed by thematic analysis to identify common porous FCS, C&S practices, and reasons for surface selection. Based on these interview data and Extension Cooperator feedback, pathogen persistence and removal by C&S will be determined for porous FCS coupons (25 cm²) under a variety of experimental parameters. Pathogens include Listeria monocytogenes (5 strain cocktail), Salmonella enterica (5 strain cocktail), Shiga toxin-producing Escherichia coli (STEC; 4 strain cocktail), Tulane virus (TuV; human norovirus surrogate), and Aichivirus A (AiV; same virus family as Hepatitis A virus). Additional experimental factors include i) bacterial pre-growth conditions such as low water activity, minimal medium, temperature stress; ii) inoculation matrix (wet vs. dry); and iii) FCS cleanliness (clean vs. visibly dirty). Microbial persistence and/or growth (bacteria only) on six porous FCS over a 7-day period under four temperatures (32°C, 27°C, 21°C, 15°C) at 50% relative humidity will be determined. Efficacy of C&S treatments for surfaces under the aforementioned parameters will also be determined. Three sanitizers are proposed for evaluation with formulations including peroxyacetic acid + hydrogen peroxide, isopropyl alcohol, and chlorine dioxide. Upon study completion, specific, data-driven guidance for C&S of common, porous FCS utilized by growers with medium, small, very small, and limited season operations will be provided.