Bill Marler’s literature review over the past four days, particularly today’s 4th installment, should cause you to wonder not "has my raw milk-based cheese been properly aged for 60 days according to legal requirements," but "whether my raw-milk based cheese was made by a cheesemaker whose production methods and raw materials ensure a safe product."  Those seem to be the best, if not only, lines of defense against producing and selling uncontaminated cheese from unpasteurized raw materials. 

Experimental studies of the behavior of pathogens in aged cheese show mixed results (Bachmann 1995; Back 1993; D’Amico 2008a; D’Amico 2008b; D’Amico 2010; Govaris 2002; Marth 1969; Reitsma 1996; Schlesser 2006). The studies are difficult to compare because of different experimental methods, and variations in how the cheese was manufactured for the experiments. For example, Reitsma (1996) found viable E. coli O157:H7 in cheddar cheese at 158 days, but used pasteurized milk in their comparisons. Schlesser (2006) inoculated cheddar cheese with a 5-strain E. coli O157:H7 cocktail and demonstrated an inadequate reduction at 60 days (1 log) and 120 days (2 logs); in contrast, heat treating the milk resulted in a 5-log reduction. D’Amico (2010) examined the behavior of E. coli O157:H7 in aged Gouda and stirred-cured cheddar cheeses manufactured from raw milk and was able to recover viable cells for more than 270 days in both cheese types using selective enrichment.

270 days is obviously 210 days beyond the mandatory 60 day aging period for raw milk-based cheeses set forth at Title 7 of the Code of Federal Regulations, section 58.439.  See also, part 1, part 2, and part 3 of Bill’s articles on the 60 day aging requirement. 

From Part 1:

A study in the December 1, 2010 issue of the Journal of Food Protection documents survival of E. coli O157:H7 in aged Gouda and stirred-curd cheddar cheese (D’Amico 2010). The authors conclude that “the 60-day aging requirement is based on decades-old research indicating that Brucella abortus is eliminated in cheddar cheese alone is insufficient to completely eliminate levels of viable E. coli O157:H7 in Gouda or stirred-curd cheddar cheese manufactured from raw milk contaminated with low levels of this pathogen.“

Very clearly, 60 days is not enough; the rule is misleading and ineffective; and cheesemakers should not rely on that standard as any kind of a prophylactic against the spread of disease.  Nor can adherence to that standard any longer be a valid reason for having less than exemplary manufacturing and sanitation methods in the production environment, and perhaps more importantly, requiring that the source of raw materials be a licensed, inspected, and reliable supplier.