Cultivation of a Cheesemonger

A Blog of Cheese Culture and Cultures

Creation of the ‘Pasteurization or 60 Day’ Regulation

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Okay, let’s get to what we came here for

History of Milk Pasteurization in the U.S.

The pasteurization or aging of cheese was not regulated in the U.S. until 1949.  Before then, there were only few preexisting standards by the FDA – standards of identity for only three American varieties of cheese – cheddar, colby, and washed curd and soaked curd cheese – were essentially quality control measures dictating milkfat content and production methods that contained no reference to pasteurization or aging.

Prior to WWII, production in the American cheese industry was very similar to the practices found in Europe.  Cheese manufacture was confined to smaller farms which drew on local milk supplies.  It was not until cheese manufacturing was made at such a large-scale industrial process that milk from many dairy farms from multiple states was needed to enter the cheese production facilities.  It was this interstate shipment and combining milk sources that put milk-safety in danger.  The FDA had to acknowledge the dangers of the new cheese production procedures and in response, instituted pasteurization and aging requirements.

On February 21, 1947, the FDA first revealed its concern for pasteurization and aging in a Notice of Hearing for the adoption of several dozen new standards of identity. Without discussing its reasons, the agency proposed to modify the three existing standards and to have all of the new standards require either aging or the use of pasteurized milk in manufacturing.  The final rulemaking release from April 22, 1949, offered the FDA’s rationale for the standards of identity which survive to this day:

“Consumers expect, and have a right to expect, that manufacturers of cheese shall take reasonable precautions to render the finished cheese safe for human consumption. Under present conditions reasonable caution on the part of manufacturers of cheese intended for human consumption without further processing requires that the milk used be pasteurized, or in the alternative that such cheese, after manufacturing, be held for a period whereby it can reasonably be expected that it will be safe for human consumption. It will promote honesty and fair dealing in the interest of consumers to include in the definition and standards of identity of the different varieties and classes of cheese requirements that the milk used be pasteurized or the cheese held for a period whereby it may be reasonably expected that the cheese will be rendered safe. Based on the best evidence available now it is reasonable to require that when the milk used in manufacturing cheese is not pasteurized the cheese be held after it is manufactured for not less than 60 days at temperatures of not less than 35◦F.”

The FDA’s strong concern for consumer expectations of safety led it to set the aging requirement at 60 days with very little scientific evidence to support such a specific duration regardless of cheese variety.  In its rule-making release, the agency admitted as much:

“Viable pathogenic microorganisms in cheese, even when present to such an extent as to be capable of causing disease in humans, tend to die when the cheese is held for some time at temperatures above 35◦F. It is not known with certainty how long cheeses must be held before they become safe. . . .No outbreak has been reported from cheese held 60 days or more.”

The Health Research Group of Public of Public Citizen petitioned the Secretary of the Department of Health and Human Services (HHS) to promulgate a regulation banning all sales, interstate and intrastate, of raw milk and milk products in the United States on April 10, 1984.  After a few months, the citizens’ group then filed suit in federal district court to compel HHS to promulgate such a rule.  The court ordered HHS to respond to the petition, finding that there had been unreasonable delay.  The Commissioner of Food and Drugs then denied the petition, forcing the Health Research Group to seek judicial review. This time, its request for relief also challenged the agency’s failure to terminate the stay of the 1973 regulation which had required pasteurization of fluid milk products through standards of identity.  In Public Citizen v. Heckler , the court ruled that the denial of the petition had been arbitrary and capricious, and ordered the FDA to institute rule-making procedures for a regulation banning the interstate sale of all raw milk and milk products.

And so, nearly three years later, on June 11, 1987, the FDA proposed a rule requiring mandatory pasteurization for all milk and milk products in final package form intended for direct human consumption.  The relevant portion of the rule was promulgated as originally proposed and is contained today in 12 C.F.R. §1240.61:

“No person shall cause to be delivered into interstate commerce or shall sell, otherwise distribute, or hold for sale or other distribution after shipment in interstate commerce any milk or milk product in final package form for direct human consumption that has not been pasteurized except where alternative procedures are provided by regulation, such as Part 133 of this chapter for curing of certain cheese varieties.”

The regulation applies to cheese as it applies to any other milk product and incorporates the standards of identity in 12 C.F.R. §133 for purposes of allowing certain cheeses to be aged at least 60 days instead of made from pasteurized milk.

However, it wasn’t until, academic researchers in South Dakota took on the experiment of bacteria survival on raw milk in 1995 and demonstrated that Esherichia coli O157:H7 (E. coli) bacteria could survive the 60-day aging period.  These results suggested that existing regulations were insufficient to protect consumers from pathogens and that all cheese, whether fresh or aged over 60 days, should be made from pasteurized milk.  Three years later, a trade group consisting of large-scale manufacturers of both specialty cheeses and process cheeses created a compilation of such relevant studies and contacted the FDA.

That same year, the FDA announced that it would research whether pathogenic bacteria contained in raw milk cheese could survive the 60-day aging period.  Such a discovery would justify a complete ban on interstate sales of raw milk cheese, making the current regulations even more restrictive.  The FDA’s studies were funded by former President Clinton’s Food Safety Initiative and conducted by government researchers at the National Center of Food Safety and Technology in Chicago.

In summary, the studies found that in the event that 60-day aging is found to be inadequate to provide the appropriate level of public health protection, an evaluation of alternative control measures would assist the agency in the development of policy in this area. Validation of the effectiveness of current or alternative process control measures used in the manufacture of aged hard cheese would result in a greater assurance of a safe food supply and enhanced public confidence in these products.

However, the controversy was not finished yet.  Catherine W. Donnelly, a professor in food microbiology at the University of Vermont, conducted an independent review of the FDA study as well as the 1995 South Dakota study.  Donnelly found two critical flaws in the design of the 1995 South Dakota study of E. coli: (1) the researchers had injected strains of E. coli into cheddar samples made from pasteurized milk, and (2) the samples were injected with several thousand times more bacteria than could realistically enter cheese during the manufacturing process.

The first design flaw meant that E. coli bacteria were never exposed to lactic acid during fermentation, as would normally happen in manufacture of cheese from raw milk. The high acidity that occurs naturally in the cheese making process helps kill pathogens. The second design flaw meant that the South Dakota study might have produced overly pessimistic and alarmist results.

Publication of Donnelly’s independent research and activism by the Cheese of Choice Coalition produced sufficiently negative publicity that the FDA’s review lost its priority status in 2002.

As of when the referenced document was published, the FDA’s results, scheduled for release in September of 2002, have not been released.

Next Posts: Pushback from Artisinal Cheesemakers

and What’s the Appeal of Raw Milk Cheese?


(1) Knoll, Laura P., Origins of the Regulation of Raw Milk Cheeses In the United States, April 26, 2005

This paper is submitted in satisfaction of the Food and Drug Law course paper and the Written Work Requirement at Harvard Law School.


One thought on “Creation of the ‘Pasteurization or 60 Day’ Regulation

  1. Thanks Mia! It seems that a study where e. coli was injected into a pasteurized cheese would also fail to observe the protective, competitive value of good microbes in raw milk cheese. I wonder if anyone has done a comparative study with raw vs pasteurized cheeses contaminated post-production.

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