To investigate the persistence of Map during the manufacture and ripening of Cheddar cheese which will contribute to a more accurate risk assessment for this organism in food (dairy) and food processing operations.<P>
The work also aims to investigate the thermotolerance and clumping phenomenom of this potential human pathogen through a proteomics approach.
Progress: Two culture media have been identified which can be used to enumerate Map during the laboratory manufacture and ripening of Cheddar cheese. A laboratory-scale Cheddar cheese production system (manufacture, vacuum packaging and ripening), simulating commercial Cheddar production has been used in conjunction with the identified culture medium to study the persistence of Map over the manufacturing process and six month ripening period.
Results to date demonstrate the persistence of three Map strains (a type strain and two isolates from pasteurized milk) throughout the first six months of ripening with D-values between 80 – 110 days for the strains tested. Results also indicate recovery of a small percentage of the Map load in the whey fraction during the process.