Guidelines To Validate Control of Cross-Contamination during Washing of Fresh-Cut Leafy Vegetables

Abstract

The U.S. Food and Drug Administration requires food processors to implement and validate processes that will result in significantly minimizing or preventing the occurrence of hazards that are reasonably foreseeable in food production. During production of fresh-cut leafy vegetables, microbial contamination that may be present on the product can spread throughout the production batch when the product is washed, thus increasing the risk of illnesses. The use of antimicrobials in the wash water is a critical step in preventing such water-mediated cross-contamination; however, many factors can affect antimicrobial efficacy in the production of fresh-cut leafy vegetables, and the procedures for validating this key preventive control have not been articulated. Producers may consider three options for validating antimicrobial washing as a preventive control for cross-contamination. Option 1 involves the use of a surrogate for the microbial hazard and the demonstration that cross-contamination is prevented by the antimicrobial wash. Option 2 involves the use of antimicrobial sensors and the demonstration that a critical antimicrobial level is maintained during worst-case operating conditions. Option 3 validates the placement of the sensors in the processing equipment with the demonstration that a critical antimicrobial level is maintained at all locations, regardless of operating conditions. These validation options developed for fresh-cut leafy vegetables may serve as examples for validating processes that prevent cross-contamination during washing of other fresh produce commodities.

Microbial Contamination of Fresh Produce: What, Where, and How?

“…This can lead to the spread of pathogenic microorganisms between clean and contaminated plants (Baert et al., ; Gil, Selma, Lopez‐Galvez, & Allende, ; Holvoet, Jacxsens, Sampers, & Uyttendaele, ; Luo, ). Cross contamination may occur due to the transport of microorganisms via washing water, particles present in the water (that is, soil and small plant fragments), or plant to plant contact (Gombas et al., ). Factors such as the configuration of the washing system, type and quality of product, product to water ratio, and the type and concentration of antimicrobial treatment, if used, will influence the ability of a given product washing system in preventing cross contamination (Gombas et al., ).…”

“…Cross contamination may occur due to the transport of microorganisms via washing water, particles present in the water (that is, soil and small plant fragments), or plant to plant contact (Gombas et al., ). Factors such as the configuration of the washing system, type and quality of product, product to water ratio, and the type and concentration of antimicrobial treatment, if used, will influence the ability of a given product washing system in preventing cross contamination (Gombas et al., ). The efficiency of antimicrobial treatments used can also be affected by the presence of high organic matter content in washing water, resulting from the accumulation of soil, debris, and cut‐produce tissue fluids from RTE crops (Allende, Selma, Lopez‐Galvez, Villaescusa, & Gil, ; Luo, ).…”

Efficacy of Chlorine, Chlorine Dioxide, and Peroxyacetic Acid in Reducing Salmonella Contamination in Wash Water and on Mangoes Under Simulated Mango Packinghouse Washing Operations

“…The chemical oxygen demand (COD) was chosen as an estimate of organic load in the wash water and was measured using the dichromate reactor digestion method (Gonzalez et al, 2004;Davidson et al, 2014;Gombes et al, 2017;Teng et al, 2018). In order to simulate commercial process water, wash water samples were collected from a commercial packing house and COD was estimated.…”

Modeling of Free Chlorine Consumption and Escherichia coli O157:H7 Cross‐Contamination During Fresh‐Cut Produce Wash Cycles

“…The pH was relatively stable during washing, with a slight decrease in pH for all products tested. The pH was below the recommended upper limit of 7.0 for maximizing the concentration of hypochlorous acid, the form of chlorine with the highest efficacy against microorganisms (Deborde & von Gunten, ; Gombas et al., ). We expect no significant changes in our model parameters due to this pH change.…”

“…The question above relates to determining the functional form of both and . It should be noted that the efficacy of sanitizers in produce wash water depends primarily on their concentration as they have very short time span (order of seconds) to influence cross‐contamination (Gombas et al., ). In the context of fresh‐cut produce washing, this indicates that the forms of and should explicitly depend on C .…”