title: Decontamination of Salmonella, Shigella, and Escherichia coli O157:H7 from leafy green vegetables using edible plant extracts.
abstract: Fresh cilantro, parsley, and spinach are products that are regularly consumed fresh, but are difficult to decontaminate, as a result, they are common vehicles of transmission of enteropathogenic bacteria. In this study, the efficacy of plant extracts as alternatives for disinfection of cilantro, parsley, and spinach that were artificially contaminated with Salmonella, Escherichia coli O157:H7, and Shigella sonnei was determined. Edible plant extracts obtained using ethanol as the extraction solvent were tested to determine the minimum bactericidal concentration (MBC) and those that exhibited the lowest MBC were selected for further studies. Leaves of fresh greens were washed with sterile water and dried. For seeding, leaves were submerged in suspensions of 2 different concentrations of bacteria (1.5 × 10(8) and 1 × 10(5) ), dried, and then stored at 4 °C until use. To determine the effects of the extracts, inoculated leafy greens were submerged in a container and subjected to treatments with chlorine, Citrol®, or selected plant extracts. Each treatment type was stored at 4 °C for 0, 1, 5, and 7 d, and the bacterial counts were determined. From the 41 plant extracts tested, the extracts from oregano leaves and from the peel and pulp of limes were found to be as effective as chlorine or Citrol® in reducing by > 2 logs, the population of pathogenic bacteria on leafy greens and therefore, may be a natural and edible alternative to chemicals to reduce the risk of Salmonella, E. coli O157:H7 and S. sonnei contamination on leafy vegetables.
  
  
  CONCLUSIONS
  The antimicrobial efficacy of the extracts of Mexican lime and oregano was clearly demonstrated on cilantro, parsley, and spinach. The extracts of Mexican lime and oregano provide alternatives to chlorine to significantly reduce bacterial pathogens that have been associated with outbreaks from contaminated leafy green vegetables. A simple, low cost, and labor-saving extraction system for production of the extracts was used.
authors: Dept. de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Univ. Autónoma de Nuevo León, Apdo, Postal 124-F, San Nicolás, Nuevo León, México 66451.
authors: Nydia
authors: N
authors: Orue
authors: Santos
authors: S
authors: García
authors: Peter
authors: P
authors: Feng
authors: Norma
authors: N
authors: Heredia
mesh_terms: D002957:Citrus / Q000737:chemistry; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D028526:Coriandrum / Q000187:drug effects / Q000382:microbiology; D003666:Decontamination / Q000379:methods*; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D008826:Microbial Sensitivity Tests; D031341:Origanum / Q000737:chemistry; D028528:Petroselinum / Q000187:drug effects / Q000382:microbiology; D010936:Plant Extracts / Q000494:pharmacology*; D012475:Salmonella / Q000187:drug effects* / Q000254:growth & development; D012760:Shigella / Q000187:drug effects* / Q000254:growth & development; D018724:Spinacia oleracea / Q000187:drug effects / Q000382:microbiology; D014675:Vegetables / Q000187:drug effects / Q000382:microbiology*
chemical_list: D010936:Plant Extracts