raw milk jpgRaw milk-based cheeses must be aged for a minimum of 60 days. The requirement appears at Title 7 of the Code of Federal Regulations, section 58.439. Recent recalls and outbreaks, along with a host of other recent raw milk-based cheese contamination events, makes you wonder whether 60 days is really enough aging time to make raw milk cheese safe to enjoy.  What is the 60 days based on?  Why not 59?  Why not 61?

Of course, its entirely possible that it is, and that the contamination in these recent events, including the recent cheese E. coli outbreak and listeria recalls, are from the production environment problems (cross-contamination), rather than within the cheesemaking ingredients themselves (feces in raw milk). Here is some literature on aging that I have found:

Any other literature on the topic?  I feel this issue needs some discussion.

  • Bill Anderson

    60 Days is a totally arbitrary number, not based on science or food safety. It was established in the 1950’s based on the production of cheddar, because that was how most cheese was made back then.
    Of course, back then they didn’t have to contend with modern anti-biotic resistant pathogenic organisms, brought into existance by our modern weakened immune systems due to the Standard American diet of highly processed refined sterile foods, as well as anti-biotic intensive, bio-tech intensive, grain-intensive CAFO farming methods which give birth to organisms like E. Coli O157:H7.
    Back in the 1950’s they also didn’t have a sophisticated consumer interested in old world styles of artisan raw milk cheese, like we do today.
    It is entirely possible to produce safe raw milk cheese that is only a day old. And it is possible to produce raw milk cheese that will never be safe no matter how long it is aged. It all depends upon the conditions and practices under which it is produced. The 60 day rules should be abolished and replaced with science-based regulation. The French certainly have done just fine with their diverse bounty of soft-ripened high-moisture raw milk cheeses aged only a few weeks. Why can’t Americans do the same?
    Oh wait, because we have the FDA. That’s right…

  • Carl Custer

    It’s not that the FDA didn’t know that 60 days could be insufficient to inactivate O157 for the past 4+ years. See below.
    Reminds me of FSIS and fermented sausages in the lat 80’s and early 90’s.
    It took “bodies”. Now FDA has bodies.
    Watch them leap into action. See FDA leap, Oh Oh Oh, See them run.
    Survival of a Five-Strain Cocktail of Escherichia coli O157:H7 during the 60-Day Aging Period of Cheddar Cheese Made from Unpasteurized Milk†
    National Center for Food Safety and Technology, 1Food and Drug Administration and 2Illinois Institute of Technology, Moffett Campus,
    Summit-Argo, Illinois 60501; and 3Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland 20740, USA
    Journal of Food Protection, Vol. 69, No. 5, 2006, Pages 990–998

  • Young Bill, for as much time as you spend on the internet, I am somewhat surprised that you missed these:
    Raw Milk Cheese Outbreaks – France
    De Valk, H., E. Delarocque-Astagneau, et al. (2000). “A community–wide outbreak of Salmonella enterica serotype Typhimurium infection associated with eating a raw milk soft cheese in France.” Epidemiol Infect 124(1): 1-7.
    In 1997, a community-wide outbreak of Salmonella enterica serotype Typhimurium (S. typhimurium) infection occurred in France. The investigation included case searching and a case-control study. A case was defined as a resident of the Jura district with fever or diarrhoea between 12 May and 8 July 1997, from whom S. typhimurium was isolated in stool or blood. One hundred and thirteen cases were identified. Thirty-three (83 %) of 40 cases but only 23 (55 %) of 42 community controls, matched for age and area of residence, reported eating Morbier cheese (Odds ratio: 6.5; 95 % Confidence Interval: 1.4-28.8). Morbier cheese samples taken from the refrigerators of two case-patients and one symptom-free neighbour cultured positive for S. typhimurium of the same phage type as the human isolates. The analysis of distribution channels incriminated one batch from a single processing plant. These findings show that an unpasteurized soft cheese is an effective vehicle of S. typhimurium transmission.
    Deschenes, G., C. Casenave, et al. (1996). “Cluster of cases of haemolytic uraemic syndrome due to unpasteurised cheese.” Pediatr Nephrol 10(2): 203-205.
    A cluster of four patients (1 girl, 3 boys) from a French village (2,000 inhabitants) had acute haemolytic uraemic syndrome (HUS) between March 1992 and May 1993. All had prodromes with fever and diarrhoea, then acute renal failure, anaemia, schistocytosis and thrombocytopenia. Peritoneal dialysis was carried out in three children (duration 3-12 days). The verotoxin VT2 gene was identified by polymerase chain reaction in the stools of two children. Some days prior to the diarrhoea, all children had eaten a cheese made with unpasteurised mixed cows’ and goats’ milk from the same farm. A case control study showed that the occurrence of HUS was linked to the consumption of this milk product (P = 0.006). The VT 2 gene was isolated from the cheese and from the stools of goats and cows from the farm, but not from the stools of farm employees.
    Desenclos, J. C., P. Bouvet, et al. (1996). “Large outbreak of Salmonella enterica serotype paratyphi B infection caused by a goats’ milk cheese, France, 1993: a case finding and epidemiological study.” BMJ 312(7023): 91-94.
    OBJECTIVE: To assess the magnitude of a nationwide outbreak of infection with Salmonella enterica serotype paratyphi B and identify the vehicle and source of infection. DESIGN: A case finding study of S paratyphi B infection between 15 August and 30 November 1993; a pair matched case-control study; an environmental investigation at a processing plant that produced a raw goats’ milk cheese incriminated in the outbreak; phage typing and genotyping of food and human S paratyphi B isolates. SETTING: France, 15 August to 30 November 1993. SUBJECTS: 273 patients with S paratyphi B infection; 59 pairs of cases and controls matched for age, sex, and city of residence. MAIN OUTCOME MEASURES: Numbers of cases and incidence rates by region of residence and age; matched odds ratios for dairy food preferences. RESULTS: Among the 273 cases there was one death; 203 (78%) strains belonged to phage type 1 var 3. The incidence of infection was greatest in the region where goats’ milk cheese is commonly produced. Comparison of cases and controls showed a 12-fold greater risk of illness (95% confidence interval 1.6 to 92.3) from eating brand A unpasteurised goats’ milk cheese. S paratyphi B isolates of phage type 1 var 3 were recovered from cheese A, goats’ milk at the plant processing cheese A, and goats’ milk supplied to the plant by a single farm. Genotypic IS 200 typing of food and human 1 var 3 phage type isolates showed a common IS 200 pattern. CONCLUSION: This outbreak emphasises the potential health hazards of widely distributed unpasteurised milk products in France and the need for their close bacterial monitoring.
    Dominguez, M., N. Jourdan-Da Silva, et al. (2009). “Outbreak of Salmonella enterica serotype Montevideo infections in France linked to consumption of cheese made from raw milk.” Foodborne Pathog Dis 6(1): 121-128.
    In 2006, an outbreak of Salmonella enterica serotype Montevideo infections occurred in France. A matched case-control study and microbiological, environmental, and veterinary investigations were conducted to determine the source of this outbreak. A case was defined as a resident of France in whom Salmonella Montevideo was isolated from a stool or blood specimen between October 16, 2006, and January 6, 2007. Patients were interviewed using a standardized questionnaire. Salmonella Montevideo food isolates collected in 2006 by the nonhuman Salmonella surveillance system were reviewed, and a trace-back investigation was carried out. Salmonella strains isolated in case-patients and in suspected food were subtyped by pulsed-field gel electrophoresis (PFGE). Twenty-three cases were identified. Ten (63%) of the 16 interviewed cases against only 11 (35%) of the 31 controls reported eating a soft cheese made with raw milk from cows. Contaminated cheese was traced to a single processing plant that had faced an episode of Salmonella Montevideo contamination in September-October 2006. At that time, the distribution of batches of cheese found contaminated by Salmonella Montevideo was blocked. Microbiological investigation indicated that 70% (16/23) of strains isolated from case-patients and 93% (28/30) of strains isolated from cheese produced by the incriminated plant shared indistinguishable PFGE patterns. Comparing the onset of illness of cases and cheese production time in the incriminated plant, we concluded that this Salmonella outbreak was caused by raw-milk cheese in which low-level contamination had gone undetected.
    Haeghebaert, S., P. Sulem, et al. (2003). “Two outbreaks of Salmonella enteritidis phage type 8 linked to the consumption of Cantal cheese made with raw milk, France, 2001.” Euro Surveill 8(7): 151-156.
    Salmonelloses are one are the main causes of foodborne infections in industrialised countries. In France, the incidence of human salmonellosis recorded by the National Reference Centre for Salmonella and Shigella (CNRSS) in 2001 was 21 cases per 100,000 inhabitants, and Salmonella serotype Enteritidis represented 39% of cases (1). This article reports the investigation results of two community outbreaks of salmonellosis that occurred simultaneously in the south west of France, and which were linked to the consumption of cheese made from raw milk.
    Ostyn, A., M. L. De Buyser, et al. (2010). “First evidence of a food poisoning outbreak due to staphylococcal enterotoxin type E, France, 2009.” Euro Surveill 15(13).
    At the end of 2009, six food poisoning outbreaks caused by staphylococci were reported in France. Soft cheese made from unpasteurized milk was found to be the common source of the outbreaks. Staphylococcal enterotoxin type E was identified and quantified in the cheese using both official and confirmatory methods of the European Union Reference Laboratory (EU-RL). To our knowledge, this is the first report of food poisoning outbreaks caused by staphylococcal enterotoxin type E in France.
    van Cauteren, D., N. Jourdan-da Silva, et al. (2009). “Outbreak of Salmonella enterica serotype Muenster infections associated with [unpasteurized] goat’s cheese, France, March 2008.” Euro Surveill 14(31). http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19290
    Salmonella enterica serotype Muenster (hereafter referred to as S. Muenster) is rare in France and in Europe. In France, a nationwide outbreak of gastrointestinal illness due to S. Muenster occurred during March and April 2008. Twenty-five laboratory-confirmed cases of S. Muenster were documented by telephone using a trawling questionnaire. Four patients were admitted to hospital and no death was recorded. Among the 21 interviewed cases, 16 reported consumption of goat’s cheese in the days prior to symptoms. The investigation incriminated goat’s cheese from producer X as being the most likely source of the outbreak. S. Muenster was isolated from both cases and the incriminated goat’s cheese. The pulsed-field gel electrophoresis profiles of the food isolates of producer X and the isolates from cases were indistinguishable. Following the withdrawal of the contaminated batch of cheese, the number of cases decreased to its usual level. To our knowledge, this is the first published outbreak of S. Muenster associated with food consumption in Europe.
    Vernozy-Rozand, C., M. P. Montet, et al. (2005). “Isolation and characterization of Shiga toxin-producing Escherichia coli strains from raw milk cheeses in France.” Lett Appl Microbiol 41(3): 235-241.
    AIMS: To evaluate Shiga toxin-producing Eschericha coli (STEC) prevalence in 1039 French raw milk cheeses including soft, hard, unripened and blue mould cheeses, and to characterize the STEC strains isolated (virulence genes and serotypes). METHODS AND RESULTS: STEC strains were recovered from cheese samples by colony hybridization. These strains were then serotyped and genetically characterized. These strains (32 STEC) were then recovered from 18 of 136 stx-positive samples: 19 strains had stx2 variant genes stx(2vh-a) (n = 2), stx(2NV206) (n = 2), stx(2EDL933) (n = 4) and stx2d (n = 11). Thirty strains had the stx1 gene and one strain, the eae gene. Combinations of stx2 and stx1 genes were present in 17 (81%) of the STEC strains. Nineteen strains belonged to the O6 serogroup and the other strains belonged to the O174, O175, O176, O109, O76, O162 and O22 serogroups in decreasing frequency. CONCLUSIONS: No conclusion can be drawn at the moment concerning the potential risk to consumers because the O6:H1 serotype has already been found associated with the haemolytic uremic syndrome and almost no isolate had the eae gene. SIGNIFICANCE AND IMPACT OF THE STUDY: The large number of STEC strains recovered from the cheese samples evaluated in this study emphasizes the health risks associated with raw milk cheeses. This further emphasizes the immediate need to identify and implement effective pre- and postharvest control methods that decrease STEC carriage by dairy cattle and to eliminate contamination of their cheeses during processing.

  • Bill Marler

    Do you have a copy of SCHLESSER Et Al JFP 2006?
    A conclusion:
    Populations of E. coli O157:H7 increased during the cheese-making operations as a result of concentration, growth, or both. Populations of E. coli O157:H7 in cheese aged for 60 days at 78C were reduced by 1 log from day 1 levels. These studies confirm previous reports in the literature that demonstrate 60-day aging at $28C is inadequate
    to reduce the number of viable pathogens during cheese making. The current 60-day aging period required in the manufacture of unpasteurized milk Cheddar cheeses may not provide sufficient public health protection.

  • Raw-milk based cheeses, like the gouda made by Bravo Farms that is currently linked to at least 33 E. coli O157:H7 illnesses in Arizona, New Mexico, California, Nevada, and Colorado, must be aged for a minimum of 60 days. The requirement appears at Title 7 of the Code of Federal Regulations, section 58.439.
    One has to believe that the requirement is solely an issue of public health–i.e. pathogenic bacteria in raw milk-based cheeses aged less than 60 days may survive the aging process. Is the inverse also true? Will pathogenic bacteria be totally inactived, or killed, by an aging process longer than 60 days? Or is there some wiggle room?
    One of several things happened to cause the Bravo Farms cheese E. coli outbreak. Maybe Bravo was following the law and aging at least 60 days; if so, the 60 day aging requirement certainly needs to be re-examined, particularly if even consumers knowledgeable about the rationale behind the 60 day aging requirement can’t even rely on the adequacy of the requirement, much less consumers who do not know what they are eating.
    But many artisan cheeses are aged less than 60 days, and my guess would be that most of those cheeses aged less than 60 days don’t carry a plain written warning on the label stating as much. Is it possible that Bravo was not following the requirement of 7 CFR 58.439 (there is no indication how long Bravo’s gouda is aged on its website)? Did Costco know it, and if so, was it telling consumers about it?

  • This kind of idle speculation is the stuff that fans the flames of food hysteria. No reputable cheesemaker is going to skirt the 60 day rule and to suggest otherwise – and to further suggest some kind of conspiracy between Bravo and Costco – is absurd.
    But then again, Marler’s firm has a vested interest in planting these seeds, no? (see lawsuits filed by firm against Bravo, as covered earlier in this blog).
    Cheese (made with raw milk and pasteurized milk) is made safely – and legally – every day in the US and all over the world.

  • Tami, really? Can you explain what “vested interest” I have in raising legitimate issues about the rationality of the 60 day rule? There is a growing body of literature in the US and Europe that cheese aged for 60 days – plus or minus – does not kill all pathogens. Bravo’s cheese has sickened 37, putting one in kidney failure. Clearly, something went wrong here – yes?

  • Of course, raising issues about the 60 day rule is completely legitimate – nor did I suggest otherwise. Your conspiracy theory is pretty far our there, though.
    Absolutely something went wrong at Bravo. And we don’t know what. That will have to wait for all of the various test results and etc. to come out.
    I have complete respect for you, you are brilliant at what you do. That being said, I think it’s reasonable in the context of any of your discussions about Bravo to point out that your firm has filed several cases against Bravo.

  • Doc Mudd

    Conscientious cheesemakers soil themselves when they defend industry miscreants who are documented to have produced tainted product and even poisoned people.
    I can only conclude from profuse groundless apologies that all producers and their product are suspect. Otherwise, why wouldn’t some forcefully advocate for consumer safety and police their own industry? It cannot be that so many apologists are all stupid, do they simply not care??
    Smug industry apologists have precipitated a sad turn of events for legitimate producers..if there are any out there. Damned fools, damned stubborn fools.

  • I can only conclude from profuse groundless apologies that all producers and their product are suspect. Otherwise, why wouldn’t some forcefully advocate for consumer safety and police their own industry? It cannot be that so many apologists are all stupid, do they simply not care??

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  • So let me get this strait. If we want to make milk-biased cheese we need to give it at least 60 days. And are we supposed to get the mold testing charleston thing done on top of that?