Factors that affect proliferation of Salmonella in tomatoes post-harvest: the roles of seasonal effects, irrigation regime, crop and pathogen genotype.

Main Objectives: Fresh fruits and vegetables become increasingly recognized as vehicles of human salmonellosis. Physiological, ecological, and environmental factors are all thought to contribute to the ability of Salmonella to colonize fruits and vegetables pre- and post-harvest. The goal of this study was to test how irrigation levels, fruit water congestion, crop and pathogen genotypes affect the ability of Salmonella to multiply in tomatoes post-harvest.

Internal colonization of Salmonella enterica serovar Typhimurium in tomato plants.

Several Salmonella enterica outbreaks have been traced back to contaminated tomatoes. In this study, the internalization of S. enterica Typhimurium via tomato leaves was investigated as affected by surfactants and bacterial rdar morphotype, which was reported to be important for the environmental persistence and attachment of Salmonella to plants.

Untangling metabolic and communication networks: interactions of enterics with phytobacteria and their implications in produce safety.

Recent outbreaks of vegetable-borne gastrointestinal illnesses across the globe demonstrate that human enteric pathogens can contaminate produce at any stage of production. Interactions of enterics with native plant-associated microbiota influence the microbiological safety of produce by affecting the attachment, persistence and proliferation of human pathogens on plants. Supermarket surveys have revealed that bacteria, but not fungi or mechanical damage, promote the growth of Salmonella enterica on produce.

Chlorine dioxide gas from an aqueous solution: reduction of Salmonella in wounds on tomato fruit and movement to sinks in a treatment chamber.

Chlorine dioxide (ClO2) off-gassed from an aqueous solution and reacted incrementally with potassium iodide solutions (sinks). After 30 min, 45% of the initial dose was detected as chlorite ion in the sink, whereas 35% of the initial dose was still in the source. Aqueous solutions of ClO2 can be used as a source of ClO2 gas in various laboratory experiments involving treatment of fruits or vegetables.

Applications of Chlorine Dioxide Gas for Control of Bacterial Soft Rot in Tomatoes.

Chlorine dioxide (ClO) gas was generated from a mixture of sodium chlorite and ferric chloride plus water (impregnated into zeolite) in a Tyvek sachet over a 2- or 24-h period. The gas was distributed by a fan over wound-inoculated tomato fruit (Lycopersicon esculentum) enclosed in a sealed aluminum pressure cooker. Within 24 h of inoculation with 6 log CFU of Erwinia carotovora subsp.

Reduction of poliovirus 1, bacteriophages, Salmonella montevideo, and Escherichia coli O157:H7 on strawberries by physical and disinfectant washes.

The efficacy levels of different physical and chemical washing treatments in the reduction of viral and bacterial pathogens from inoculated strawberries were evaluated. Escherichia coli O157:H7, Salmonella Montevideo, poliovirus 1, and the bacteriophages PRD1, phiX174, and MS2 were used as model and surrogate organisms. Chemicals readily available to producers and/or consumers were evaluated as antimicrobial additives for the production of washes.

Postharvest Decay Risk Associated with Hydrocooling Tomatoes.

Tomatoes (breaker stage) hydrocooled with a cell suspension of Erwinia carotovora subsp. carotovora containing 50 to 200 mg of free chlorine per liter (ppm) (10°C, pH 7) remained decay free during a 10-day storage at 20°C. Sporadic disease appeared during storage of tomatoes similarly cooled with chlorinated water containing spores of Rhizopus stolonifer.