title: Efficacy of household washing treatments for the control of Listeria monocytogenes on salad vegetables.
abstract: The efficacy of household decontamination methods at reducing Listeria monocytogenes on fresh lettuce (Lactuca sativa), cucumber (Cucumis sativus) and parsley (Petroselinum sativum) was studied. Inoculated vegetable pieces were immersed in washing solutions and surviving L. monocytogenes enumerated. Parameters investigated were storage temperature prior to washing, dipping water temperature, agitation, acetic acid concentration and immersion time. The results indicated that the storage temperature significantly affects the efficacy of dipping vegetables in water for the control of L. monocytogenes, as the reduction in count was greatest when products had been stored at cooler temperatures. Decontamination with acetic acid (up to 2.0% v/v) was shown to have some effect in most cases, but the highest observed decrease in count was 2.6 log cfu/g. Experiments investigating the effect of exposure time to acetic acid (0.5% and 1.0% v/v, up to 30 min immersion) indicated that immersing the vegetables for more than 10 min is of minimal benefit. The most significant factor affecting washing and decontamination efficacy was the vegetable itself: L. monocytogenes colonizing cucumber epidermis was far more resistant to removal by washing and to acid treatment than that on the leafy vegetables, and L. monocytogenes on parsley was the most susceptible. This shows that published decontamination experiments (often performed with lettuce) cannot necessarily be extrapolated to other vegetables.
authors.affiliation: Laboratory of Food Microbiology, Department of Food Technology, Alexandrian Technological Educational Institute of Thessaloniki, Thessaloniki, Greece.
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Nastou
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rhoades
authors.forename: Petros
authors.initials: P
authors.lastname: Smirniotis
authors.forename: Ioanna
authors.initials: I
authors.lastname: Makri
authors.forename: Michael
authors.initials: M
authors.lastname: Kontominas
authors.forename: Eleni
authors.initials: E
authors.lastname: Likotrafiti
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology; D015169:Colony Count, Microbial; D018553:Cucumis sativus / Q000382:microbiology; D003666:Decontamination / Q000379:methods*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D018545:Lactuca / Q000382:microbiology; D008089:Listeria monocytogenes / Q000187:drug effects / Q000502:physiology*; D028528:Petroselinum / Q000382:microbiology; D013696:Temperature; D013997:Time Factors; D014675:Vegetables / Q000382:microbiology*
chemical_list: D019342:Acetic Acid