sodium-hypochlorite and Salmonella-Food-Poisoning

Efficacy of sanitizers in an overhead spray and brush roller system was examined for reducing Salmonella on unwaxed, mature green tomatoes. Surface inoculated tomatoes were treated in the overhead spray system for 5, 15, 30, and 60 s. A sodium hypochlorite (NaOCl) study tested NaOCl (25, 50, and 100 mg/L) against a water control. A sanitizer study examined NaOCl (100 mg/L), chlorine dioxide (ClO₂; 5 mg/L), peroxyacetic acid (PAA; 80 mg/L), and water. The overhead spray system was also compared to a scale-model flume. All NaOCl concentrations were significantly more effective at removing Salmonella than water and achieved at least a 3-log₁₀ CFU/mL reduction at different treatment times (P < 0.05). NaOCl (100 mg/L) achieved a 4 ± 1.8 log₁₀ CFU/mL reduction at 15 s. In the sanitizer study, NaOCl, ClO₂, and PAA achieved at least a 3-log₁₀ CFU/mL reduction at 15 s and between 3.9 and 5.5 log₁₀ CFU/mL reductions at 30 to 60 s. NaOCl (100 mg/L) in the overhead spray system significantly reduced more Salmonella than in the flume at 15 to 60 s. NaOCl flume treatment only reached a 1.3 ± 1.1 log₁₀ CFU/mL reduction at 15 s. Results of this study demonstrate the ability of sanitizers in the laboratory model overhead spray system to reduce Salmonella on tomato surfaces. An overhead spray system could be implemented instead of flumes to achieve higher pathogen reduction with less water and sanitizer use, thereby lowering packing costs.. The use of a non-recirculating, overhead spray brush roller system could offer a cost effective and efficacious way of washing tomatoes. The use large communal dump tanks in tomato processing has been suspected as a source of contamination in the tomato processing process. If effective, the brush roller system could augment or possible replace currently used dump tanks.

Topics: Bacterial Adhesion; Chlorine Compounds; Colony Count, Microbial; Cost Savings; Disinfectants; Food Preservation; Fruit; Osmolar Concentration; Oxides; Peracetic Acid; Salmonella; Salmonella Food Poisoning; Sodium Hypochlorite; Solanum lycopersicum; Species Specificity; Surface Properties; Time Factors

In Rio Grande do Sul, southern Brazil, Salmonella Enteritidis is one of the principal microorganisms responsible for foodborne disease. The present study was conducted to compare the sodium hypochlorite resistance of Salmonella Enteritidis SE86 with that of other strains of Salmonella Enteritidis isolated from different regions of the world and to investigate the involvement of the rpoS and dps genes in resistance to this disinfectant. We tested five Salmonella Enteritidis wild-type (WT) strains isolated from different countries, two mutant strains of Salmonella Enteritidis SE86, and two tagged (3XFLAG) strains of Salmonella Enteritidis SE86 for their resistance to sodium hypochlorite (200 ppm). The survival of the WT and attenuated strains was determined based on bacterial counts, and tagged proteins (Dps and RpoS) were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with anti-FLAG antibodies. None of the WT strains of Salmonella Enteritidis were totally inactivated after 20 min. The SE86 strain lacking dps was more sensitive to sodium hypochlorite than was the WT SE86 strain, with a 2-log reduction in counts after 1 min. The RpoS and Dps proteins were actively expressed under the conditions tested, indicating that in Salmonella Enteritidis SE86 these genes, which are expressed when in contact with sodium hypochlorite, are related to oxidative stress.

Topics: Brazil; Colony Count, Microbial; Disease Outbreaks; Drug Resistance, Bacterial; Electrophoresis, Polyacrylamide Gel; Food Contamination; Food Microbiology; Genes, Bacterial; Humans; Microbial Sensitivity Tests; Salmonella enteritidis; Salmonella Food Poisoning; Sodium Hypochlorite

Raw sprouts have been implicated in a number of foodborne disease outbreaks. Because contaminated seeds are usually responsible, many sprout producers attempt to disinfect seeds before germination and detect sprout contamination during production. In March 2001, we detected an increased number of Salmonella serotype Kottbus isolates in California. Overall, we identified 31 cases from three western states. To identify the cause, we conducted a case-control study with the first 10 identified case-patients matched to 20 controls by age, sex, and residential area. Our case-control study found illness to be statistically associated with alfalfa sprout consumption. The traceback investigation implicated a single sprouter, where environmental studies yielded Salmonella Kottbus from ungerminated seeds and floor drains within the production facility. Pulsed-field gel electrophoresis patterns of all patient, seed, and floor drain Salmonella Kottbus isolates were indistinguishable. Most implicated sprouts were from seeds that underwent heat treatment and soaking with a 2,000-ppm sodium hypochlorite solution rather than the Food and Drug Administration (FDA)-recommended 20,000-ppm calcium hypochlorite soak. Other implicated seeds had been soaked in a calcium hypochlorite solution that, when tested, measured only 11,000 ppm. The outbreak might have been averted when screening tests of sprout irrigation water detected Salmonella in January; however, confirmatory testing of these samples was negative (but testing improperly utilized refrigerated irrigation water). Producers should use the enrichment broth of positive screening samples, not refrigerated irrigation water, for confirmatory testing. Until other effective disinfection technologies are developed, producers should adhere to FDA recommendations for sprout seed disinfection.

Topics: Adult; Aged; California; Case-Control Studies; Disease Outbreaks; Disinfectants; Dose-Response Relationship, Drug; Electrophoresis, Gel, Pulsed-Field; Female; Food Contamination; Food Microbiology; Humans; Male; Medicago sativa; Middle Aged; Salmonella; Salmonella Food Poisoning; Seeds; Sodium Hypochlorite