Reduction of the attachment, survival and growth of L. monocytogenes on lettuce leaves by UV-C stress

Inactivation of Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcus aureus by sequential light-emitting diodes (LEDs) treatment at 365 nm and 420 nm

Frequent outbreaks caused by foodborne pathogens pose long-term risks to consumer health. To proactively reduce the load of pathogenic bacteria during food processing, a novel light-based antibacterial approach was developed by sequential application of 365 nm and 420 nm light-emitting diodes (LEDs). Results demonstrated that after treatment with 365 nm (480 J/cm2) followed by 420 nm (307.2 J/cm2), the reduction of Listeria monocytogenes reached 4.05 ± 0.31 log CFU/mL, significantly higher (an additional 1.8 log CFU/mL, P < 0.05) than cumulative reductions achieved by each 365 nm (2.25 ± 0.92 log CFU/mL) and 420 nm (0.02 ± 0.15 log CFU/mL) treatments. Further analysis revealed that the enhancement in bacterial reduction achieved through the sequential treatment with 365 nm and 420 nm was primarily driven by the exposure time to 365 nm. The inactivation mechanisms were investigated, considering possible photothermal, physical, and oxidative effects. Findings showed that the antibacterial effect of sequential treatment was mainly ascribed to intracellular oxidation generated by reactive oxidative species (ROS), namely hydrogen peroxide and superoxide anion. The antibacterial mechanism of two LEDs may result from the sensitization of bacterial cells to excessive ROS, as evidenced by fluorescent intensity measurements and chemical scavenger assays. This research provides new insight for improving the efficacy of UVA and blue light treatment to control food contamination by Listeria.

Edible Coating for Fresh-Cut Fruit and Vegetable Preservation: Biomaterials, Functional Ingredients, and Joint Non-Thermal Technology

This paper reviews recent advances in fresh-cut fruit and vegetable preservation from the perspective of biomacromolecule-based edible coating. Biomaterials include proteins, polysaccharides, and their complexes. Compared to a single material, the better preservation effect was presented by complexes. The functional ingredients applied in the edible coating are essential oils/other plant extracts, metals/metal oxides, and organic acids, the purposes of the addition of which are the improvement of antioxidant and antimicrobial activities and/or the mechanical properties of the coating. The application of edible coating with other preservation technologies is an emerging method, mainly including pulsed light, short-wave ultraviolet, modified atmosphere packaging, ozonation, and γ-irradiation. In the future, it is crucial to design coating formulations based on preservation goals and sensory characteristics. The combination of non-thermal preservation technology and edible coating needs to be strengthened in research on food preservation. The application of AI tools for edible coating-based preservation should also be focused on. In conclusion, edible coating-based preservation is promising for the development of fresh-cut fruits and vegetables.