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Survie d'Escherichia coli O157:H7 et de la Salmonelle dans le cidre et le jus d'orange selon les effets de l'ozone et de la température du traitement.

Survival of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice as affected by ozone and treatment temperature.

Auteurs : WILLIAMS R. C., SUMNER S. S., GOLDEN D. A.

Type d'article : Article

Résumé

The inactivation of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice treated with ozone was evaluated. A five-strain mixture of E. coli O157:H7 or a five-serovar mixture of Salmonella was inoculated into apple cider and orange juice. Ozone was pumped into the juices maintained at 4 °C, ambient temperature (approximately 20 °C), and 50 °C for up to 240 min, depending on the organism, juice, and treatment temperature. Samples were diluted in 0.1% peptone water, and surface plated onto recovery media. Recovery of E. coli O157:H7 was compared on tryptic soy agar (TSA), sorbitol MacConkey agar, hemorrhagic coli agar, and modified eosin methylene blue agar; recovery of Salmonella was compared on TSA, bismuth sulphite agar, and xylose lysine tergitol 4 (XLT4) agar. After treatment at 50 °C, E. coli O157:H7 populations were undetectable (limit of 1.0 log CFU/ml; a minimum 6.0-log CFU/ml reduction) after 45 min in apple cider and 75 min in orange juice. At 50 °C, Salmonella was reduced (apple cider) and was undetectable in orange juice after 15 min. E. coli O157:H7 at 4 °C was reduced in apple cider and in orange juice. Salmonella was reduced in apple cider and orange juice at 4 °C. Treatment at ambient temperature resulted in population reductions of less than 5.0 log CFU/ml. Recovery of E. coli O157:H7 and Salmonella on selective media was substantially lower than recovery on TSA. Ozone treatment of apple cider and orange juice at 4 °C or in combination with mild heating (50 °C) may provide an alternative to thermal pasteurization for the reduction of E. coli O157:H7 and Salmonella in apple cider and orange juice.

Détails

  • Titre original : Survival of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice as affected by ozone and treatment temperature.
  • Identifiant de la fiche : 2005-1379
  • Langues : Anglais
  • Source : Journal of Food Protection - vol. 67 - n. 11
  • Date d'édition : 11/2004

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