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Cross-contamination is a key food safety risk during both harvesting and post-harvest processing of fresh produce. Very few effective intervention approaches are available for reducing cross-contamination risks from diverse food contact surfaces during harvesting and post-harvest processing. Therefore, developing an effective antimicrobial coating that can be simply applied on a diversity of food contact surfaces is highly desirable. This work demonstrates a cost-effective and one-step antimicrobial coating approach that can be applied on diverse food contact surfaces, such as plastic films, Sparta brushes, and polyfoam sponges. The incorporation of chlorine charged antimicrobial yeast cell wall particles (YCWPs) into chitosan-based coatings provides unique advantages in achieving a high concentration of chlorine on food contact surface and extending the stability of chlorine. Approximately 583 nmol/cm2 of active chlorine bound to the coated poly(vinyl alcohol-co-ethylene) (PVA-co-PE) film surface after 60 min of incubation with bleach at room temperature, which enabled a significant antimicrobial activity of this coating. An inactivation of approximately 3-log and 5-log units of Listeria innocua with organic load (COD = 500 mg/L) were achieved after treatment for 2 min and 5 min, respectively. This antimicrobial coating with chlorine charged YCWPs effectively reduce the cross-contamination between fresh produce and plastic films. Baby spinach leaves were selected as a model fresh produce. The results represent that chitosan-YCWPs coatings led to more than 3 log reduction in the bacterial population transferred to leaf surface upon 10 min of contact with contaminated plastic films, while native chitosan without chlorine charged YCWPs coating did not result in any significant reduction. The results in this study also demonstrate the feasibility of using this antimicrobial coating on contaminated sponges and brushes to reduce cross-contamination of fresh produce during washing steps. No bacterial cells were detected from the leaf surface after contact with contaminated sponges or brush samples coated with chitosan and chlorine-charged YCWPs. This cost-effective and one-step antimicrobial coating approach with a high potential of scale-up will significantly enhance the efficacy of surface sanitation and prevent the cross-contamination of fresh produce. |
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