Evaluation of a modified method for the detection of oocysts on spinach leaves.
Fiche publication
Date publication
décembre 2020
Journal
Food and waterborne parasitology
Auteurs
Membres identifiés du Cancéropôle Est :
Pr VILLENA Isabelle
Tous les auteurs :
Razakandrainibe R, Kubina S, Costa D, Robinson G, La Carbona S, Aubert D, David A, Gargala G, Villena I, Favennec L, Chalmers RM
Lien Pubmed
Résumé
Despite the infection risk associated with the consumption of contaminated food, techniques for recovering and detecting oocysts from fruit and vegetables are generally inadequate due to the variable recovery efficiencies and high reagent costs, such as those presented by ISO 18744:2016 "Microbiology of the food chain -Detection and enumeration of and in fresh leafy green vegetables and berry fruits". Although an improved method for recovering these parasites from Iceberg lettuce, which reported increased recovery efficiency as well as lower costs, has been published, it appears to have limitations for the recovery of from saponin-rich leaves such as spinach (), which have previously been implicated in outbreaks. In this study, we refined the method to improve its use with these more challenging samples. The use of alkaline elution buffer (1 M glycine) of different pH values was evaluated for their effectiveness in removing from spinach leaves. The refinement of Utaaker's method showed, from spinach leaves inoculated with 100 oocysts, an increased oocyst recovery rate with an overall mean recovery rate of 33.79% ± 2.82%. The emergence of parasitic foodborne illnesses and outbreaks associated with the consumption of fresh produce demonstrates the need for the development of an optimal recovery process for parasites from suspected foods. Results showed that refinement of existing protocols could improve the retrieval of oocysts from these more challenging leafy greens.
Mots clés
Cryptosporidium parvum, Modified method, Oocyst recovery, Spinach, Spinacia oleraceae
Référence
Food Waterborne Parasitol. 2020 Dec;21:e00097