Increases in foodborne disease outbreaks associated with fresh produce have necessitated the need to identify potential sources of microbial contamination in produce and agricultural environments. The present study evaluated Salmonella prevalence and serovar diversity in show the potential of agricultural fruit production environments to act as reservoirs of clinically important Salmonella serovars.

A broad orange biome was described with pyrosequencing and gave insight into the likely survival and persistence of pathogens, especially as they may affect the quality and safety of the packed product. A close examination of the microbiota of fruit and the impact of intervention strategies on the ecological balance may provide a more durable approach to reduce losses and spoilage.

Foodborne disease outbreaks involving fresh produce have increased in recent years. The risk of infection from contaminated food is worsened by the increased prevalence of antibiotic-resistant strains. This study evaluated the prevalence of antibiotic resistance in Salmonella isolates (n = 263) from agricultural production systems through to the final packed product. Salmonella isolates were preliminarily identified by matrix-assisted laser desorption ionization-time-of-flight mass spectroscopy (MALDI-TOF MS) and API 20E and identities confirmed by invA gene polymerase chain reaction. Antimicrobial susceptibility was performed with 15 antimicrobial agents using the Kirby-Bauer disk diffusion test. Of the 263 Salmonella isolates assessed, 59.3% were resistant to one or more antimicrobials. The most frequently detected resistance was against chloramphenicol and kanamycin (46.7%), trimethoprim-sulfamethoxazole (28%), and streptomycin (14%), and the less frequently detected resistance was toward ampicillin (1.14%), amikacin (0.76%), and amoxicillin-clavulanic acid (0.38%). Multiple antimicrobial resistance (MAR) (resistance to ≥3 antibiotics) was found in 48.7% (76/156) isolates. The most common MAR phenotype was to chloramphenicol and trimethoprim/sulfamethoxazole-kanamycin (43.6%). Resistance to chloramphenicol, kanamycin, or trimethoprim/sulfamethoxazole was only observed in MAR phenotypes. All isolates were susceptible to ceftiofur, cefoxitin, ceftriaxone, ciprofloxacin, nalidixic acid, gentamicin, and tetracycline. This study confirms the importance of fresh produce production environments as potential reservoirs and fresh produce as carriers of antibiotic-resistant Salmonella spp. with significant clinical importance. Further studies to evaluate the actual level of health risk from these pathogens should include characterization of the antibiotic resistance determinant genes among the isolates.

This study investigated microbial population shifts on citrus carpoplane and the impact of irrigation and packhouse processing water in four commercial farms. Samples included oranges (n = 450) and water (n = 230). Mean microbial concentrations ranging from 1.6 to 3.6 log colony forming units (CFU)/cm2 were detected on unwashed fruit and were reduced at least by 2.0 log CFU/cm2 for bacteria, 0.8 log CFU/cm2 for fungi and 1.3 log CFU/cm2 for yeasts during washing with disinfectants and/or fungicides. Occasional spikes in concentration (mostly for bacteria) were observed following some packing steps including washing, fungicide treatment, waxing, and final packing. Evaluation of Escherichia coli O157:H7 and S. Typhimurium survival in fungicides typically used during packhouse processing showed them to be susceptible to guazatine, imazalil, philabuster, and ortho‐phenyl phenate. Both tested pathogens were able to survive in thiabendazole, fludioxinil and pyremethanil, except for S. Typhimurium in fludioxinil where it died within 4 hr of incubation. Practical applications Understanding the impact of current intervention strategies on the ecological balance of the citrus carpoplane may provide a more durable approach to reduced losses and spoilage and in developing crop‐specific management systems for food safety assurance. Our study showed process‐by‐process changes in microbial loads naturally present on healthy citrus fruit at harvest. Washing baths containing a sanitizing agent consistently reduced initial microbial loads on the citrus carpoplane. Further, potential survival of E. coli O157:H7 and S. Typhimurium in currently registered commercial postharvest fungicides, was demonstrated. The pesticide fludioxinil was observed to be effective against, S. Typhimurium providing some potential use as a kill step agent, which, however, needs further investigation.

Wastewater handling has been associated with an increased risk of developing adverse health effects, including respiratory and gastrointestinal illnesses. However, there is a paucity of information in the literature, and occupational health risks are not well quantified. Grab influent samples were analysed using Illumina Miseq 16S amplicon sequencing to assess potential worker exposure to bacterial pathogens occurring in five municipal wastewater treatment plants (WWTPs). The most predominant phyla were Bacteroidota, Campilobacterota, Proteobacteria, Firmicutes, and Desulfobacterota, accounting for 85.4% of the total bacterial community. Taxonomic analysis showed a relatively low diversity of bacterial composition of the predominant genera across all WWTPs, indicating a high degree of bacterial community stability in the influent source. Pathogenic bacterial genera of human health concern included Mycobacterium, Coxiella, Escherichia/Shigella, Arcobacter, Acinetobacter, Streptococcus, Treponema, and Aeromonas. Furthermore, WHO-listed inherently resistant opportunistic bacterial genera were identified. These results suggest that WWTP workers may be occupationally exposed to several bacterial genera classified as hazardous biological agents for humans. Therefore, there is a need for comprehensive risk assessments to ascertain the actual risks and health outcomes among WWTP workers and inform effective intervention strategies to reduce worker exposure.