FDA Study Reviews Effectiveness of Cheddar Cheese Aging Process

A recent study by the U.S. Food and Drug Administration (FDA) confirms that the 60-day aging process increases the safety of cheddar cheese. The results of the study were published in the May 2006 issue of the Journal of Food Protection.

FDA conducted the study to determine whether the 60-day minimum aging period had any effect on the safety of cheese made with milk that was either raw or heat treated. The current federal standard for cheddar cheese requires that the milk used for making cheddar cheese must be pasteurized or the cheese must be cured at a minimum temperature of 35°F for at least 60 days.

During the study, cheddar cheese made from unpasteurized milk was inoculated with a cocktail of Escherichia coli 0157:H7, and samples were collected during the manufacturing process. Although populations of E. coli increased during the cheese making operation, they decreased during the 60-day ripening period.

The study found a reduction in the number of pathogens, even in cheddar cheese made with raw milk. For cheddar cheese made from heat-treated milk, the combined heating and aging process offered a high level of protection from the pathogens. FDA expressed some concern, however, that the 60-day aging process may not be sufficient to eliminate all pathogens for cheddar cheese made with raw milk, although the agency does not plan any further action to change current regulations.

The study also shows that 60-day aging may not completely eliminate pathogens that potentially could be reintroduced during cheese ripening, though IDFA feels current practices allay this concern.

"In today's modern dairy plants, the likelihood of recontamination after heat treatment is unlikely to begin with," said Allen Sayler, IDFA senior director of regulatory affairs. "In addition to very stringent internal cheese plant processing controls, state and federal employees regularly conduct inspections to evaluate the safety of the cheese manufacturing process."

Most cheese manufacturers use pasteurized milk for making cheddar cheese, and of those using unpasteurized milk, the vast majority heat-treat the milk they use to make cheddar cheese.

For more information, contact Sayler at asayler@idfa.org or 202-220-3544.

Posted May 22, 2006