The food industry is facing a major transition regarding methods for confirmation, characterization, and subtyping of Salmonella . Whole-genome sequencing (WGS) is rapidly becoming both the method of choice and the gold standard for Salmonella subtyping; however, routine use of WGS by the food industry is often not feasible due to cost constraints or the need for rapid results. To facilitate selection of subtyping methods by the food industry, we present: (i) a comparison between classical serotyping and selected widely used molecular-based subtyping methods including pulsed-field gel electrophoresis, multilocus sequence typing, and WGS (including WGS-based serovar prediction) and (ii) a scoring system to evaluate and compare Salmonella subtyping assays. This literature-based assessment supports the superior discriminatory power of WGS for source tracking and root cause elimination in food safety incident; however, circumstances in which use of other subtyping methods may be warranted were also identified. This review provides practical guidance for the food industry and presents a starting point for further comparative evaluation of Salmonella characterization and subtyping methods.

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Aims: Inactivating microbial contaminants in fresh produce commonly uses chlorine washing. The effectiveness of ozone was explored as an alternative to chlorine in produce washing for ensuring microbial safety while maximizing water reusability. Methods and Results: An ozone washing system was designed to permit continuous addition of contaminated produce and the reuse of washing water. The effectiveness of ozonation (<2 mg l À1 ) was determined using Bacillus subtilis spores as a stricter measure of efficiency with processing time of 10 min. As a comparison, chlorine (c. 100 mg l À1 ) was tested in parallel. Water quality characteristics, including chemical oxygen demand, total suspended solids, disinfectants concentration and microbial reduction were measured. Ozonation showed an average of 1Á56 log reduction of B. subtilis spores on lettuce, while chlorination achieved a 1Á30 log reduction. The effluents after ozonation demonstrated improved water quality, both in physicochemical quality and microbial quality compared to chlorination. Conclusion: Aqueous ozone treatment is effective against microbial contaminants on fresh produce and enables extended use of washing water. Significance and Impact of the Study: The results provide significant data about ozone disinfection efficacy and its impact on the water reusability, which can facilitate the ozone utilization in the fresh produce production as an environmental friendly alternative.

Aims: The internalized human pathogens in fresh produce are not effectively removed during conventional washing, and therefore, it may cause foodborne illness when the produce is consumed raw. Thus, effective nonthermal processes are needed to prevent this risk. Methods and Results: Green fluorescence protein-tagged Salmonella Typhimurium was either sprayed on the surface of iceberg lettuce or injected into the bottom part (bulb) of green onions to induce bacterial internalization. The contaminated vegetables were collected after 2 days and subjected to surface disinfection. Different fluencies of UV-C radiation (75-900 mJ cm À2 )and two fluencies of UV-C (450, 900 mJ cm À2 ) combined with chlorine and peracetic acid (PAA) were applied to the produce to examine the inactivation efficiency of internalized bacteria. A range of 1Á96-2Á52 log reduction in the internalized Salmonella was achieved when the lettuce was treated with higher UV-C fluency (150, 450, 900 mJ cm À2 ) or UV-C combined with chemical disinfectants. Significant reduction (1Á00-1Á49 log CFU g À1

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