Synergistic antimicrobial activity of food-grade compounds in wax coatings on fruits during wax drying

Wax coatings are used in various fruit and vegetable products, including citrus, apples, peaches, cucumbers, and avocados, to improve the shelf life of fresh produce. In many industries, particularly citrus and apple, wax coatings are air dried using hot air. Although wax coatings improve the shelf life by reducing the loss of moisture, they have a limited impact on the inactivation of microbes on the fruit surface. To enhance the reduction of bacteria on fruit surfaces and to reduce the risk of cross-contamination during the wax coating process, this proposal aims to develop a synergistic antimicrobial approach that can be combined with wax coating and drying. The specific goals of this project are to (a) Assess the synergistic interaction of LAE and other food-grade compounds or extracts with mild heat to achieve rapid inactivation of bacteria inoculated in a wax suspension; (b) Assess the role of synergistic treatment) in the inactivation of the pathogens inoculated in a wax composition and pathogens inoculated on the surface of apples and citrus fruits; and (c) Evaluate the influence of the optimal synergistic treatments on the quality, microbial load, and shelf life of fruits.

This project aims to enhance the inactivation of bacteria on wax coatings and fruit surfaces during the wax coating drying process. The proposed enhanced inactivation of bacteria on wax coating and fruit surfaces will be achieved using a synergistic antimicrobial approach proposed in this research. This synergistic inactivation of bacteria is based on the combined effect of selected GRAS compounds added to commercial wax compositions with mild heat-assisted drying of wax coatings. Overall, this research is motivated by the needs of the fresh fruit industry to improve the safety of fresh fruits during postharvest processing. This research project focuses on both citrus and apple fruits. The specific goals of this project are to (a) assess the synergistic interaction of LAE (Ethyl lauroyl arginate) and other food-grade compounds or extracts with mild heat to achieve rapid inactivation of bacteria inoculated in a wax suspension; (b) evaluate the role of synergistic treatment in the inactivation of pathogens inoculated in a wax composition after coating on citrus fruits and apples; (c) demonstrate the efficacy of synergistic treatment to inactivate pathogenic inoculated on the surface of apples and citrus fruits; and (d) evaluate the influence of the optimal synergistic treatments on the quality, microbial load and shelf life of fruits. The success of this research will reduce the cross-contamination risks from wax compositions and brushes and improve fresh fruit safety by reducing the bacterial load on the fruit surface.

(1) Assess the synergistic interaction of LAE and other food-grade compounds or extracts with mild heat to achieve rapid inactivation of bacteria inoculated in a wax suspension (2) Assess the role of synergistic treatment (optimal combination of food-grade compounds in a wax coating and mild heat identified in Aim 1) in the inactivation of the pathogens inoculated in a wax composition on the surface of apples and citrus fruits (3) Measure the influence of synergistic treatment in the inactivation of the pathogens inoculated on the surfaces of apples and citrus, including the stem and calyx regions (4) Evaluate the influence of the optimal synergistic treatments identified in Aims 2 and 3 on the quality (including color), microbial load (endogenous), and shelf life of fruit during storage

This project is ongoing. A final report will be provided when the project is finished.