Cultivation of a Cheesemonger

A Blog of Cheese Culture and Cultures

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Raw Milk Products in the U.S., Volume 3: Artisans’ Response to FDA Regulations

In March 2000, Oldways and the The American Cheese Society joined forces to assemble an international coalition- the Cheese of Choice Coalition – in response to the murmurs that the Food and Drug Administration (FDA) was threatening to change the regulations about the sale of raw milk cheeses.  The United States allows the sale of raw milk cheeses aged for more than 60 days, under the assumption that 60 days of aging is enough for the acids and salts in cheese to help protect against harmful pathogens like listeria, salmonella, and E. coli. The coalition’s mission is to fight to preserve the rights of individuals to buy unpasteurized (raw milk) cheeses. (Oldways) Raw milk activist and naturopathic physician Ron Schmid characterizes microbiopolitics of pasteurized milk this way: “Pasteur’s mechanistic understanding of disease took away the individual’s power to prevent it, and placed the mandate to cure squarely in the hands of the medical professionals” (Paxson) . For Schmid, the the power to prevent illness from raw milk consumption includes both government regulations and knowledge in medical professionals as well as careful production practices by the individual. That milk from small herds of grass-fed cattle that never see a feed lot contains beneficial bacteria to cultivate diverse intestinal flora and fauna that could enable the human body to protect itself from disease.  After Pasteur, the realm of food safety has practically became a medicalization of food and eating and people want to be able to accept in the potentialities of collaborative human and microbial cultural practices.


Heather Paxson is an associate professor in MIT’s Department of Anthropology studying America’s artisanal cheesemakers, a politically mobilized group of small-scale farmers and artisans who crave the freedom to produce and eat any kind of cheese they desire, in opposition to government regulations. Paxson has defined American artisinal cheesemakers as those who use “sensory evaluation in their cheesemaking, such as running a finger through freshly set curd to decide if it’s ready to cut.” As of 2010, the number of these artisinal dairy farms in American was just under 400. (Gudrais) A handful of these creameries have been making cheese for a century or more, passing down the knowledge through generations. However, a majority of American artisanal cheesemaking began in the 1980s, and it was around this time that local farming and dairying gained popularity in a response to the ‘back-to-the-land’ movement.  Most of these new cheesemakers, serious about their craft, looked to methods tested by time by visiting Europe or corresponding with farmers there to determine which types of cheese and which grazing animals did well in climates similar to the locations of their own creameries. (Gudrais) The larger part of raw milk cheeses made in the US are made on a very small scale with milk from the maker’s own animals or from neighboring farms and without factory equipment.  Compared to industrial cheese manufacturing facilities, the risk of contamination is non-existent for these small-scale family farmers – such as the Lazor family.

Ann & Jack Lazor on Butterworks Farm


For the cheesemaker, the difference between pastuerization and raw milk is that pastuerization neutralizes enzymes and bacteria that develop the unique textures and flavors and produce character and complexity unique to that cheesemaker’s cheese. Many claim that it is impossible to find in that from pasteurized milk. (Although, it must be said that there are great cheeses made from pastuerized milk.) It is also claimed that pasteurization destroys enzymes and bacteria that have health benefits.  The French go as far as to call cheese made from pasteurised milk as dead cheese – and that is the whole point of the pasteurisation process — death. Although the Food and Drug Administration states pasteurization reducing milk’s nutritional value as a myth, (FDA) there is no mention by the FDA about having pasteurized cheese that is great tasting. 

 All cheese producers, industrial and artisan alike, face restrictions on getting raw-milk cheese to U.S. markets. By U.S. law (21 CFR 133.182), cheese made from raw milk must be aged at least 60 days at a temperature no less than 1.7◦C (35◦ F) before being sold or imported. The 60-day rule means to offer protection against pathogenic microbes that could thrive in the moist environment of a soft cheese.  While the FDA views raw-milk cheese as a potential biohazard, riddled with bad bugs, aficionados see it as the reverse: as a traditional food made by the action of “good” microorganisms—bacteria, yeast, mold—on proteins found in milk that serve to protect the cheese from more harmful microflora. However, The FDA’s rules are not about to loosen. But if artisanal cheese-makers can’t alter America’s pasteurization laws, what options remain for them? 


And so, cheesemakers have learned how to adapt by refining their craft within America’s long-standing rules.  Paxson noted that as a result, some cheesemakers have developed their own styles and what has started as a form of small-business protest could yet yield artisanal and economic innovations, altering the taste and availability of cheese in America. “They can make an unpasteurized bloomy rind cheese, like a Camembert, last eight weeks, while in France it might last four weeks.” Other cheese-makers are taking commercially available bacterial cultures,” says Paxson “and figuring out how to blend them to get that rich and complex flavor” even with pasteurized milk. This still fits within her view of what it is to be an artisanal cheesemaker in the first place: “To have a feel for the milk, to have a sense of how to adjust the process in response to changes in the milk.” Moreover, Paxson says, “People are saying Americans are getting better at making cheese from pasteurized milk than the Europeans are, because they’ve had to.” (Dizikes)

Corporate dairies can live within the rules. In fact, through heavy lobbying of state and federal governments they write regulations to suit their operations. But for the niche dairy farmers, the same regulations are major impediments for their livelihood. It’s an strange situation – while politicians decry the demise of the family farm, they pass laws that in the name of food-safety that undermine these enterprising farmers. In terms of food safety, however, the US government says it knows best, and, what’s good for the giant dairies is good for the small family-size dairy farm. The government writes a single set of regulations that are designed for the huge dairy farms and dairies, where the many aspects of producing milk and milk products are all separated. Unlike small-scale farms, no one person is directly involved in all operations in a corporate dairy. No one is suggesting overthrowing the FDA—a safe food supply is not to be underestimated—however, a curious mix of political libertarians and foodies is questioning some of the motives and logics underpinning the Pasteurian food regime.

In the meantime, I find it absolutely thrilling to see that American can-do attitude in full force that when someone or something – even our own government – stands in our way of our dreams, we become more creative, clever, and resourceful in order to adapt. I think that the beauty of American artisinal cheeses is that we are not like Europe, but completely our own.  It is the struggles and challenges that the small-scale dairy farmers have faced that have given the most flavor to their cheese.  While the Coalition will continue to fight for the freedom to create young, unpasteurized cheeses, I am curious to see, to be able to witness, the creations that occur in the aging caves in the U.S.

Raw Milk Products in the U.S.: Volume 1: You Sell Raw Milk Cheese? Is That True?


Raw Milk Products in the U.S.: Volume 2: Creation of the “Pasteurization or 60 Day” Regulation



Dizikes, Peter. Against the common gouda: The government regulates how food is produced. MIT anthropologist Heather Paxson studies the rebellious cheese-makers who reluctantly adhere to those rules. MIT News, October, 2009

FDA. The Dangers of Raw Milk: Unpasteurized Milk Can Pose a Serious Health Risk. 08/22/2012

Gudrais, Elizabeth. American Cheese Cultures. Harvard Magazine, January-February 2010

Hall, Ross Hume. Will Fears of Germs Stymie a Small Farm Revival in the U.S.?. The Ecologist. June, 2001

Oldways and the Cheese of Choice Coalition

Paxson, Heather. Post-Pasteurian Cultures: The Microbiopolitics of Raw-Milk Cheese in the United States. Cultural Anthropology, Vol. 23, No. 1 (Feb., 2008), pp. 15-47


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Food for Thought: Cheese as Model Microbial Ecosystem – The Research of Rachel Dutton

This past Tuesday, I attended a talk by Rachel Dutton, doctor and Bauer Fellow, at Princeton University entitled “Food for Thought: Cheese as Model Microbial Ecosystem.”  I was invited by my friend, Alan, whom I met in Florence this past summer and is attending Princeton for his master’s in synthetic organic chemistry (Hi, Alan!)

Unfortunately, I cannot give a summary of her talk because it was a presentation of data on a project that is not yet complete.  However, she was able to send me some really amazing photos of microbes on cheese.

microflora on Cabot Clothbound Cheddar

microflora on Cabot Clothbound Cheddar

What I can share is the work that Rachel Dutton has done up to now.


Rachel’s lab is located at Harvard University, in the FAS Center for Systems Biology.  The goal of her research is to identify the mechanisms and principles through which microbial communities function.  Coming to an understanding of the formation, function, and evolution of microbial ecosystems is seen as one of the most important challenges facing microbiology.

Rachel has observed that  “microbes usually do not exist as individuals in nature, but as part of complex, multi-species communities, however, microbes have traditionally been studied as individuals in the laboratory.”

The Dutton lab “will apply a range of culture-dependent and independent methods to study the microbial diversity in the surface-associated communities that make up the rind, on identifying and characterizing inter-species interactions, and on developing an experimental model system to study microbial ecosystems.” (Bauer Fellows Profile)

In order to fully understand how microbes function within the context of the complex communities in which they exist outside of the laboratory, model systems are needed.  The lab found cheese rinds to serve as that model system.  The lab studies patterns in natural microbial cheese communities and then tests hypotheses in the lab with in vitro models of community formation with a mixture of dried cheese curd powder and agar. (The Dutton Lab Website)



Determine the Flavors, Smells, and Textures

Rachel Dutton is attracted to cheese because of the simplified, experimentally tractable microbial ecosystems found growing on the surface and cheeses are ideal models to study the behavior of microbes in complex communities.  These communities, and their rich assembly of metabolic capacities, contribute much of the diversity in flavors, smells, and textures of the hundreds of different varieties of cheeses.  Camembert is covered entirely of microscopic organisms that contribute to the creation and consistancy of the paste, the unique flavors, and the familiar bloomy white rind.

Are Able to Communicate

The technical term for this community of organisms is ‘biofilm’ – a web of interconnected microbes that rely on each other to create their own environment.  Interestingly, biofilms are not just a large swath of microbes, but organized masses of organisms that have been proven to have communication capabilities. In a process called quorum sensing, individual cells constantly send out and measure chemical signals.  Through these chemical signals, if a bacterium or fungus can recognize enough of its own kind (or enough other species) in the area, the cells switch from acting as individuals to acting as part of a community of connected organisms.

Protect the cheese

With the addition of  strands of protein and sugars, the microbes weave themselves with these other molecules to become much tougher.  This toughness proves beneficial for cheesemakers in that the biofilm resists the growth of undesirable bacteria and mold, while regulating the flow of gas and moisture into and out of the cheese.

Can Have an Extremely Diverse Community

Industrial cheesemaking techniques ensure that cheeses are inoculated with just one or two key species, so a commercial Brie might be dominated by only a single strain of Penicillium camemberti. While this method does keep cheese production consistent, it doesn’t provide complex, interesting flavors as found on many artisinal cheeses.

Cheesemakers carefully control each element in a cheese’s creation so that the right milk is colonized by the right bacteria and fungi at the right time.  Cheese aging caves are kept at specific temperatures and humidities to cultivate desired species of fungi.  Any slight adjustment in these numbers could cause an explosive bloom of an unwanted microbes.

The students in Rachel Dutton’s undergraduate lab class at Harvard analyzed the rind of Winnimere, a cheese produced at Jasper Hill Farm, VT, and

Winnimere Cheese from Jasper Hill Farm (

found an “exceptionally cosmopolitan” community of microorganisms living there.  The rind of Jasper Hill’s Winnimere is washed in beer brewed from microbes living in the cheese’s aging cave. It was not unexpected that many salt-loving (halophilic) bacteria were discovered on the rind, but what did come as a surprise was the range of other unfamiliar bugs that are also found in places like Etruscan tombs, Tunisian oil wells, or Arctic sea ice.

Culture magazine commented that the discovery of these microbes on cheese is a far cry from the “big three” that dairy scientists generally focus on: the Lactococcus bacterial strains that produce the cheese paste, the Penicillium fungi that produce blue and bloomy rinds, and the Brevibacterium that supply the pungent pieds-de-Dieu aroma of washed rinds.

While the exact role of each of the oddball microbes found in Winnimere isn’t known, it is understood that without this specific mix living on the rind, Winnimere wouldn’t have its unique flavor. The Dutton lab is working hard to figure out the purpose of each microbe, and their interaction within the larger cheese rind community.

An article in The New York Times about Rachel Dutton’s lab states that “…as word about the lab’s work spread, first among microbiologists, then among cheesemakers, Ms. Dutton’s in-box filled with requests from nonscientists, including chefs, bakers and even a pickle maker in Berkeley, Calif. Packages started showing up at her office, containing food samples for her to analyze. …Chefs are looking for a signature taste, something that is completely unique to their location. “What makes terroir is the microbes. It’s literally what’s in the air.”

“There really is no one else doing what she is doing,” said Mr. McGee, a contributor to The New York Times Dining section. “Academic microbiologists have not taken an interest in small-scale fermentation, focusing on food safety rather than food quality. There is really only one person at the moment.”  And Vince Razionale, the cheese buyer for Cambridge-based Formaggio Kitchen has said that “her work was described as “groundbreaking.”

In the bigger picture, beyond developing cheese textures and flavors, Dr. Dutton sees cheese as a model for how all kinds of microbial systems work. Helping researchers better understand microbial communities could mean that cheese could act as a proxy for the biofilm of an oil-slicked wetland or the distressed lung of a cystic fibrosis sufferer.



A majority of this post is a summarization of the article Microbe Managing – The Lifesaving Potential of Cheese Bacteria written by Will Fertman for Culture magazine.

Will Fertman. Microbe Managing – The Lifesaving Potential of Cheese Bacteria. Culture magazine, Fall 2012

Peter Andrew Smith. For Gastronomists, a Go-To Microbiologist. New York Times, September 17, 2012

FAS Center for Systems Biology Bauer Fellows Program Profile page

The Dutton Lab website

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The Ripening of a Camembert


Le Camembert,

The ripening process of cheese is very complex and involves microbiological and biochemical changes to the curd resulting in the flavor and texture characteristic of the particular variety.

Dairy fermentations involve microbial interactions at several levels.  These interactions lead to different microbiota playing their role in a succession important to the progress of the fermentation and the quality of the final product.  They take place in the form of complex interactions between the starter culture, yeast and microflora in mold-ripened cheeses

The Flora of Camembert Cheese

Although a considerable variety of molds and fungi has been observed on Camembert cheeses, a list of possibly twenty species would include those which were often found.  Among these are perhaps six species of Penicillium, two or three of Aspergillus, Geotrichum candidum (previously known as Oidium lactis)Cladosporium herbarum, one or two of Mucor, one or more of Fusarium, Monilia candida, and two species perhaps related to it, with the incidental occurrence of Acrostalagmus cinnabarinus, a Cephalosporium, various species of Alternaria, and Stysanus.  Besides these, yeasts such as Kluyveromyces lactis were found in large numbers and considerable variety in many cases.

We are just going to focus mainly on  P. camemberti and G. candidum whose mycelium development is responsible for the bloomy aspect of Camembert-type cheese.

Geotrichum candidum

It has been noted that G. candidum is abundant upon every brand of Camembert.  The wide genotypic and phenotypic diversity of Geotrichum candidum strains…[and] G. candidum possesses many different metabolic pathways that are of particular interest to the dairy industry. G. candidum is of importance in the maturation of cheese, and much is known about its direct contribution to cheese ripening and flavour formation.  Its diverse metabolic potential means that G. candidum can play an important role in the ripening of many soft and semi-hard cheeses and make a positive contribution to the development of taste and aroma. It may also influence the growth of other microorganisms, both valuable and detrimental. The significance of the presence of G. candidum in cheese depends on the particular type of production and on the presence of biotypes featuring specific types of metabolism.  However, in situ metabolic pathways involved in cheese ripening and their regulations are mainly unknown (Boutrou, Guéguen)

Penicillium camemberti

The comparison of the results  by a 1906 study done by  Charles Thom, mycologist in Cheese Investigations in the Dairy Division of the Bureau of Animal Industry, showed that a single species of Penicillium was present upon every Camembert cheese that was examined and in partially ripened cheeses this mold often covered the majority of the cheese surface.  This mold is known as “Penicillium Camemberti” or the “Camembert mold.”  This species develops a large and characteristic growth of aerial mycelium in addition to a densely felted mass of white threads which penetrate the surface of the cheese for 1 or 2 mm. and largely constitute the rind.

During aging, Geotrichum candidum and yeasts grow initially, but they are soon followed by a dense growth of Penicillium camemberti:

Microbial count on acidified potato dextrose agar medium (pH 3.5) of the K. lactis LMA-437 (●), G. candidum LMA-436 (□), and P. camemberti (▲) ripening culture.

Salts migrating to the rind

Salts are ionic compounds that result from the neutralization reaction of an acid and a base.  Both lactate, from lactic acid, and Calcium (Ca) and Phosphate (PO4)  are defined in chemistry as salts.  P. camemberti and G. candidum oxidatively metabolise lactate to CO2 and water, deacidifying the cheese surface and resulting in a higher pH at the rind of the cheese.   This deacidification causes a pH gradient to develop from the center of the cheese to its surface and this established pH gradient of decreasing values towards the center of the cheese causes lactate to migrate towards the surface where it is used as a carbon source by P. camemberti.   As the cheese continues to age and the microbes continue to metabolize, pH increases to about 7.0 in the outer part of the cheese and about 5.5 in the centre.  The change of pH is most pronounced on the surface of the cheese, which is covered by the white mycelium of the P. camemberti after a week of maturation.  When lactate becomes depleted, casein, a milk protein, is then metabolised.

Calcium phosphate, found in high quantities in or on the casein micelles, is also soluble in acid environments, and as the pH of the surface of the cheese decreases, calcium phosphate migrates towards the surface of the cheese, where it then precipitates as a layer of Ca3 (PO4)2.  This migration results in a calcium phosphate gradient from centre to surface and  the depletion of calcium phosphate in the center of the cheese assists in the development of the desired soft texture of the cheese.  Reduction in the concentration of calcium phosphate, together with increased pH and proteolysis (the breakdown of proteins – casein proteins in this case) results in softening of the interior, which is characteristic of mature Camembert-type cheese.

Further metabolisation of casein results in the formation of ammonia from amino acids.  In very mature cheese, ammonia is produced at the surface from proteins and diffuses into the curd.  A cheese that smells very strongly of ammonia is extremely old and probably should not be eaten.

Enzymes migrating into the paste

The proteinases (enzyme that conducts proteolysis) from P. camemberti  migrate very slowly into the cheese, and only reach a depth of about 6mm from the surface.  This means that their direct participation in the enzymatic reactions deep in the interior of the cheese is limited.  The important enzymatic activities in the interior of the cheese are caused by the enzymes from the rennet, the plasmin from the milk and enzymes from the lactic acid starter cultures.

Final Thoughts

The French have been producing Camembert cheese for hundreds of years.  The creamy consistency and delicious, earthy flavors (flavor chemistry is a post I hope to tackle soon) all result from ambient fungi.  While it is true that some cheesemakers spray the necessary fungi on their cheeses in the aging caves, there are still many that allow the fungi to settle naturally  to ripen the cheese.  It is interesting to me – and I hope I have enlightened you as well – about what you’re eating and the relationship between you and the fungi on the cheeses you love.   The research on cheese microflora continues today – there are many studies and unanswered questions.



Marie-Hélène Lessard,  Gaétan Bélanger, Daniel St-Gelais, and Steve Labrie. The Composition of Camembert Cheese-Ripening Cultures Modulates both Mycelial Growth and Appearance. Appl Environ Microbiol. 2012 March; 78(6): 1813–1819.  doi: 10.1128/AEM.06645-11   last accessed: 11/16/2012

Paul L. H. McSweeney, Biochemistry of Cheese Ripening, Vol 57, No 2/3 May/August 2004 International Journal of Dairy Technology.   Dept. of Food and Nutritional Sciences, University College, Cork, Ireland.  last accessed: 11/16/2012

Charles Thom. Fungi in Cheese Ripening: Camembert and Roquefort. U.S. Department of Agriculture, Bureau of Animal Industry, Bulletin No. 82. 1906. last accessed: 11/16/2012

Herbert William Conn. The Camembert Type of Soft Cheese in the United States. U.S. Department of Agriculture, Bureau of Animal Industry, Bulletin No. 75. 1905

Karl Esser, ed. The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research: Industrial Applications X, 2nd ed. Dec 1, 2010

Boutrou R, Guéguen M. Interests in Geotrichum candidum for Cheese Technology Int J Food Microbiol.  2005 Jun 25;102(1):1-20.

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Creation of the ‘Pasteurization or 60 Day’ Regulation

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.

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You sell raw milk cheese? Is that true?

cheeses at the shop where I work

Customer: “The card on this cheese says that it is made from raw milk… is that true? I didn’t think they were allowed to sell raw milk cheese…”

Me:  “It is raw milk, but it’s been aged for at least 60 days…as per the USFDA regulations”


This question has come up more than once.  And so, it got me to thinking, what is the story behind this 60-day rule?

While doing research for the answer to this question, I came across many other topics that may help give you, the reader, a better and more comprehensive understanding of raw and pasteurized milk and milk products in the United States. And so, I realized that in order to properly tell this story I’ll have to let it unfold in multiple parts.  First, I’ll give a brief background on what raw milk is, the ways milk can become contaminated, and the pasteurization of milk as per the regulations of the U.S. Food and Drug Administration.  Next, I’ll go ahead and look into the story of how the regulation developed throughout history, and perhaps address various states’ regulations regarding raw milk sales and European regulations regarding the manufacture and sales of raw milk and fresh cheese as well as a discussion of the flavor of pasteurized versus unpasteurized cheeses.  For now, let us begin with the basics:

What is Raw Milk?

Raw milk is un pasteurized milk from cows, goats, sheep, or other animals.  It is thought, but not known exactly, that less than 1% of milk sold to consumers in the United States has not been pasteurized.

What Contaminates Could Be Found In Raw Milk?

According to the Center for Disease Control (CDC), raw milk can carry harmful bacteria and other germs that can make you very sick or kill you.  A wide variety of bacteria (e.g.,  Brucella, Campylobacter, Listeria, Mycobacterium bovis (a cause of tuberculosis),Salmonella, Shiga toxin-producing Escherichia coli [e.g., E. coli O157], Shigella, Yersinia), viruses (e.g., norovirus), and parasites (e.g., Giardia) that can make people sick or on few occasions, be fatal are sometimes found in raw milk.  The CDC also states that while it is possible to get foodborne illnesses from many different foods, raw milk is one of the riskiest of all.

These bacteria, viruses, and parasites may introduce themselves to milk through many different routes, such as:

• Cow feces coming into direct contact with the milk
• Infection of the cow’s udder (mastitis)
• Cow diseases (e.g., bovine tuberculosis)
• Bacteria that live on the skin of cows
• Environment (e.g., feces, dirt, processing equipment)
• Insects, rodents, and other animal vectors
• Humans, for example, by cross-contamination from soiled clothing and boots

What Is Pasteurization?

Pasteurization is the process of heating milk to a high enough temperature for a long enough time to kill illness-causing bacteria contained in the milk and is the only way to kill many of the bacteria in milk that can make people very sick.

According to Code of Federal Regulations Title 21, Volume 8, Section 1240.61 (Revised as of April 1, 2012), the terms “pasteurization,” “pasteurized,” and similar terms shall mean the process of heating every particle of milk and milk product in properly designed and operated equipment to one of the temperatures given in the following table and held continuously at or above that temperature for at least the corresponding specified time:

Milk Pasteurization Regulations According to 21CFR1240.61

Is Pasteurization 100% Effective?

Pasteurized milk products have occasionally caused illnesses and outbreak because of germs introduced in the dairy after the pasteurization process. However, pasteurized milk that is correctly handled in the dairy, bottled, sealed, and refrigerated after pasteurization, and that is properly handled by the consumer, is very unlikely to contain illness-causing bacteria. Considering the amount of pasteurized milk consumed in the United States, illness from it is exceedingly rare.



(1) Raw Milk Questions and Answers, Center For Disease Control and Prevention Website  Last Accessed: November 4, 2012

(2) 21CFR1240.61  Last Accessed: November 4, 2012