How Long Should Cheese Be Aged? Will the Rules Be Changed?

Cheese Both cheesemakers and foodies are wondering and worrying about what the FDA will do next. 

Since 2009, the agency has been studying the question of whether 60 days of aging is sufficient to make cheeses produced with unpasteurized (raw) milk safe.  The fear is that the government might

a) lengthen the aging time period

b) forbid the use of raw milk in certain types of cheeses or even

c) ban the use of raw milk in cheeses altogether.


Why would any of these actions be taken, and what would be lost as a result?


The New York Times explains, “The new proposals…come after a very rough year for this country’s fast-growing gourmet cheese industry, marked by recalls and two multiststate E.coli outbreaks that sickened nearly 50 people.”  Greater safety is the government’s goal.


Since the 1940s, the 60-day aging rule has been in effect.  The belief was that, since raw milk has not been pasteurized to kill pathogens, aging is needed to allow the natural chemicals in cheese—the acids and salt—to destroy harmful bacteria.  However, scientists now believe that the 60-day rule is an inadequate guideline because different types of cheeses need different aging periods in order to be safe.


The manufacturers of artisan cheeses, along with their customers, claim that these cheeses have special unique flavors which are destroyed by pasteurization. Furthermore, an extension of the 60 days to 90 days might make it impossible for cheesemakers to produce some popular cheeses (such as blue cheese) because they don’t lend themselves to such prolonged aging.  Even worse is the fear that some gourmet cheesemakers—right now a thriving part of the agricultural scene—might suffer financially or even be put out of business.


But the health dangers from cheeses made with raw milk are real.  A 2008 study showed that listeria levels actually increases in some soft cheeses (for example, brie) as they aged, making them even more of a health threat.  The reason is that soft cheeses contain more moisture and, as they age, less acid, both conditions that allow bacterial growth.  One 2010 study showed that E.coli could survive in cheese for more than a year. However, there are additional safety issues with some artisan cheeses.  Some experts say that improved sanitation and more testing of  the products would make these cheeses safer.


We asked one of our Advisory Board members, Dr. Clair Hicks, a specialist in cheese, to comment on the aging of raw milk cheeses, and here’s what he told us: “If the cheese is imported and not labeled pasteurized, the consumer should age it  (in the refrigerator) for at least 90 days.  Why 90 days?  After 90-plus days of storage, the normal flora of bacteria in the cheese will overwhelm the listeria, and their numbers will fall to the point where they cannot be detected.”


“I would never recommend that a person, pregnant or otherwise, eat a fresh non-domestic, non-pasteurized soft cheese that had been aged less than 90 days.  The risk is just too high,” says Hicks. But here’s the catch: he adds, “The 90-day aging would eliminate the consumption of many soft cheeses because they don’t hold up for that many days of storage.”


For further information on this topic on Shelf Life Advice, click here:


Source(s): “Raw Milk Cheesemakers Fret Over Possible New Rules” “Raw milk debate simmers as states, FDA mull rules”


Clair L. Hicks, Ph.D., University of Kentucky, Dept. of Animal and Food Sciences


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