Camembert-type cheese quality and safety implications in relation to the timing of high-pressure processing during aging

摘要

Bloomy rind cheeses, including Brie, Camembert,and related varieties, are at high risk of contaminationby environmental pathogens during manufacture andripening. This risk is particularly high during ripeningdue to open-air exposure of the product. Currently, nokill step is applied after manufacture or post ripeningto control food safety risks associated with Listeriamonocytogenes contamination. Instead, cheesemakersmust rely on sanitation and environmental monitoringto reduce this risk. High-pressure processing (HPP) isa nonthermal food-processing technology that can effectivelyreduce bacterial contaminants with minimalimpact on the organoleptic properties of various foods.The objective of this study was to evaluate HPP as apotential intervention to maintain Camembert cheesequality and reduce risk associated with L. monocytogenes.Timing of HPP treatments (3, 11, and 45 d aftermanufacture) was based on the growth of L. monocytogenesduring Camembert cheese ripening. High-pressureprocessing treatment of fully ripened cheeses (45 d) resultedin destruction of the surface mold, which causedbrowning and yellowing of the cheese rind. ApplyingHPP treatment earlier in the ripening process (11 d)resulted in a similar degradation of cheese appearance,which did not improve with continued ripening. ApplyingHPP treatment shortly after production (3 d;before the surface flora developed) delayed the developmentof the cheese rind and the textural ripening of thecheese. This early treatment time also resulted in freewhey being expelled from the cheese, creating a firmerbody. Applying HPP 11 d after manufacture resultedin >5 log reduction of L. monocytogenes at 450 and 550MPa with holding times of 10 min. Although HPP waseffective at reducing L. monocytogenes associated withbloomy rind cheeses, the quality deterioration wouldbe unacceptable to consumers. Cheesemakers mustcontinue to emphasize sanitation and environmentalmonitoring to reduce the risk of L. monocytogenes inbloomy rind cheeses.