title: Survival of Mycobacterium avium subsp. paratuberculosis in ultra-filtered white cheese.
abstract: Mycobacterium avium subsp. paratuberculosis (Map) is considered as a potential public health threat due to its possible association with Crohn's disease in humans. This study aimed to investigate the survival of Map in ultra-filtered white (UFW) cheese, with special reference to the effect of initial inoculum level, addition of starter culture and salt concentration. Behaviour of Map was monitored during the storage of UFW cheese using F57-quantitative real-time PCR and culture assay. According to the results, higher inoculum level prolongs Map persistence in UFW cheese. Furthermore, the addition of starter culture was found as the main restrictive parameter affecting the survival of Map in UFW cheese. Meanwhile, salt concentration did not accelerate Map inactivation. It was concluded that UFW cheese has potential to support the survival of Map.
  
  
  CONCLUSIONS
  This study was conducted to investigate the factors that influence the survival of Mycobacterium avium subsp. paratuberculosis (Map) during the storage period of ultra-filtered white (UFW) cheese which represents a step forward to meet a critical industry need. Results revealed that the addition of starter culture could restrict the persistence of Map, while Map survival was not affected by higher salt concentration. In addition, persistence of Map was found dose-dependent. It was concluded that in UFW cheese, Map could survive the 60 days of storage period.
authors.affiliation: Department of Food Science and Technology, Tabriz Branch, Islamic Azad University, Tabriz, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Hanifian
mesh_terms: D000818:Animals; D002611:Cheese / Q000382:microbiology*; D061353:Food Storage; D008892:Milk / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction
keywords: F57-quantitative real-time PCR; Mycobacterium avium subsp. paratuberculosis; UF-white cheese; inoculum level; salt; starter culture