title: Inactivation of Listeria monocytogenes using Water Bath Heat Treatment in Vacuum Packed Ricotta Salata Cheese Wedges.
abstract: Ricotta salata cheese is frequently contaminated on the surface with Listeria monocytogenes. Water bath heat treatment in vacuum packed whole ricotta salata cheese wheels demonstrated to be effective in inactivating L. monocytogenes. However, the risk of cross-contamination in ricotta salata wedges is increased during cheese cutting. Therefore, the effectiveness of heat treatment in ricotta salata wedges has to be demonstrated conducting a new validation study. In this study, 9 different time temperature combinations, 75, 85, and 90 °C applied for 10, 20, and 30 min each, were tested on artificially contaminated ricotta salata cheese wedges. The extent of the lethal effect on L. monocytogenes was assessed 1 and 30 d after the application of the hot water bath treatment. Five of 9 combinations, 75 °C for 30 min, 85 °C for 20, and 30 min, and 90°C for 20 and 30 min, demonstrated to meet the process criteria of at least 5 log reduction. Sensory analyses were also conducted in order to account for the potential impact on sensory features of ricotta salata wedges, which showed no significant differences between treatments.
  
  
  CONCLUSIONS
  This study allowed to select water bath heat treatments of vacuum packed ricotta salata wedges effective to reduce L. monocytogenes contamination. Such treatments can be successfully applied by food business operator to meet compliance with microbiological criteria through the designated shelf-life.
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Spanu
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Christian
authors.initials: C
authors.lastname: Scarano
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Spanu
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Pala
authors.affiliation: Depto. per la Ricerca nelle Produzioni Animali, Loc. Bonassai, S.S. 291 Sassari-Fertilia - Km., 18600, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Di Salvo
authors.affiliation: Depto. per la Ricerca nelle Produzioni Animali, Loc. Bonassai, S.S. 291 Sassari-Fertilia - Km., 18600, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Piga
authors.affiliation: Cooperativa Allevatori Ovini Formaggi Soc. Coop. Agricola, Loc. "Perda Lada" Fenosu, 09170, Oristano, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ullu
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Casti
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Lamon
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Cossu
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Ibba
authors.affiliation: Dept. of Veterinary Medicine, Univ. of Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: Enrico Pietro Luigi
authors.initials: EP
authors.lastname: De Santis
mesh_terms: D000328:Adult; D002611:Cheese / Q000382:microbiology*; D005260:Female; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling; D005516:Food Microbiology; D018857:Food Packaging; D006358:Hot Temperature; D006801:Humans; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013649:Taste; D014618:Vacuum
keywords: Listeria monocytogenes; post-lethality treatment; sens ry properties; whey cheese