title: Comparison of different washing treatments for reducing pathogens on orange surfaces and for preventing the transfer of bacterial pathogens to fresh-squeezed orange juice.
abstract: The objectives of this study were to compare the effectiveness of various washing treatments for reducing Escherichia coli O157:H7, Salmonella sp., and Listeria monocytogenes populations on orange surfaces and to measure the effect of some of these treatments in  preventing the transfer of pathogens during juice extraction. Orange surfaces inoculated with L. monocytogenes or a mixture of E. coli O157:H7 and Salmonella Typhimurium were washed by water spray and then sprayed with or dipped in water at 80°C for 1 min, 70% ethanol  for 15, 30, or 45 s or 1, 2, or 4 min, 2 or 4% lactic acid solution at 55°C for 15, 30, or 45 s or 1, 2, or 4 min, or 200 mg/liter hypochlorite at pH 6.5 or 10 for 15 s. The surviving populations of these pathogens on the oranges were enumerated after each treatment. In a further stage,  the ability of these pathogens to be transferred to the juice during extraction was tested. Juice was obtained from inoculated oranges that were subjected to selected treatments using chlorine, lactic acid, ethanol, and hot water as described above, and then bacterial counts in orange juice  were determined. The application of these treatments reduced the populations of pathogens on orange surfaces by 1.9 to >4.9 log, 1.9 to >4.6 log, and 1.4 to 3.1 log cycles for E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes, respectively. The treatments  using hot water or lactic acid showed greater reductions than other treatments. The time, antimicrobial concentration, and form of application affected the bacterial reduction. All treatments resulted in undetectable counts in the juice. Nevertheless, pathogens were recovered by the enrichment-plating  method. Treatment of oranges before juice extraction may reduce the risk associated with consuming orange juice.
authors: Departamento de Farmacobiología, Universidad de Guadalajara, Guadalajara, Jalisco 44430, México.
authors: N E
authors: NE
authors: Martínez-Gonzáles
authors: L
authors: L
authors: Martínez-Chávez
authors: C
authors: C
authors: Martínez-Cárdenas
authors: A
authors: A
authors: Castillo
mesh_terms: D001628:Beverages / Q000382:microbiology*; D032084:Citrus sinensis / Q000382:microbiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development; D000431:Ethanol / Q000494:pharmacology; D005506:Food Contamination / Q000032:analysis* / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006801:Humans; D006997:Hypochlorous Acid / Q000494:pharmacology; D007773:Lactates / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development; D012475:Salmonella / Q000187:drug effects / Q000254:growth & development; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000494:pharmacology
chemical_list: D007773:Lactates; D014867:Water; D000431:Ethanol; D006997:Hypochlorous Acid