title: Survival kinetics of Mycobacterium bovis during manufacture and ripening of raw milk Cheddar and Caerphilly cheese produced on a laboratory-scale.
abstract: OBJECTIVE
  Persistence of Mycobacterium bovis was investigated in UK raw milk cheeses.
  
  
  RESULTS
  Replicating traditional cheese production methods under stringent CL3 containment conditions, Cheddar and Caerphilly cheeses were produced with Myco. bovis inoculated raw milk. High-inoculum investigations used three Myco. bovis genotypes; later low-inoculum investigations used only Myco. bovis AF2122/97. High-inoculum Cheddar (n = 9) and Caerphilly (n = 9) were matured for a minimum of 12 and 4 months respectively; maturation of low-inoculum Cheddar (n = 3) and Caerphilly (n = 3) was up to 11 weeks. Survival of Myco. bovis was monitored by enumeration at different points throughout cheese manufacture and ripening. D values were calculated as follows: 57 and 59 days in high-inoculum Cheddar and Caerphilly, respectively, and 41 and 24 days in low-inoculum Cheddar and Caerphilly respectively.
  
  
  CONCLUSIONS
  Mycobacterium bovis is concentrated in cheese curd and a proportion lost with the whey. Reduction in viability during manufacturing is limited, while significant Myco. bovis inactivation occurs during maturation. Inactivation was improved, during Caerphilly ripening, when acid development was enhanced by increasing the proportion of starter culture.
  
  
  CONCLUSIONS
  Mycobacterium bovis inactivation data obtained could be used to inform assessment of the risk posed to consumers by raw milk dairy products.
authors: Food Microbiology, Queen's University Belfast, Belfast, UK. r.forgrave@qub.ac.uk.
authors: R
authors: R
authors: Forgrave
authors: Sustainable Agri-Food Science Division, Agri-Food and Biosciences Institute (AFBI), Belfast, UK.
authors: J A
authors: JA
authors: Donaghy
authors: Sustainable Agri-Food Science Division, Agri-Food and Biosciences Institute (AFBI), Belfast, UK.
authors: A
authors: A
authors: Fisher
authors: Food Microbiology, Queen's University Belfast, Belfast, UK.|Sustainable Agri-Food Science Division, Agri-Food and Biosciences Institute (AFBI), Belfast, UK.
authors: M T
authors: MT
authors: Rowe
mesh_terms: D000818:Animals; D002611:Cheese / Q000382:microbiology*; D019649:Food Industry; D005516:Food Microbiology; D007700:Kinetics; D050296:Microbial Viability; D008892:Milk / Q000382:microbiology; D009163:Mycobacterium bovis / Q000302:isolation & purification*
keywords: 
  Mycobacterium bovis
  ; cheese manufacture; cheese ripening; food safety; raw milk; survival kinetics