Don’t be afraid!
As a person who tends to want to follow rules, it is sad to be reminded that a good portion of food production regulations have little to do with actual food safety, rather they are the result of a ponderous, rigid system that steam rolls forward, sometimes based more on the ease of generalizing rather than the complexity of reality. The FDA has never liked wood shelves, especially when you sit food, in this case naturally rinded cheese, directly on its porous surface. Wood does not fit their Good Manufacturing Practice (GMP) model for a cleanable surface. While wood aging shelves have technically never been okay with the FDA, they have until now been mostly ignored and the decision to allow them been left to individual states .In many” big cheese” states, the regulators defer to the scientific knowledge of the leading expert within each state. For example, in both Oregon and Wisconsin (where at least 30 million pounds of cheese is aged on wood each year) the departments of agriculture have an official stance of “no wood shelves”. But in both states if a cheesemaker gets a thumbs up from the academic expert regarding their maintenance protocol for the shelves, then they have been allowed.
Isn’t that sensible? Did you hear me mention the words “scientific knowledge”? Let’s review what is well researched and known about wood shelves. (I’ll give you some references at the end of this post). Guess how many outbreaks of food borne illness they have been implicated in since the dawn of cheesemaking? Zero. This doesn’t mean that pathogens can’t exist on a wood shelf. If a cheese is contaminated and the wood poorly cared for, it will pass it to the shelf, no matter what material it is made from. Contamination of any aging shelf can happen when poor practices occur at any stage of cheese production, but it is not any more likely when wood is used. Bottom line.
Pros and Cons
So why do cheesemakers and affinuers (the folks that age cheese) love wood shelving? Tradition? Romance? Practicality? In the days before the invention of plastic, that ubiquitous, malleable material that we now take so for granted, wood was the logical and singular option. But fortunately it was also perfect. Like naturally aging cheese, wood “breathes”, it holds moisture without being wet, pulling it both out of the cheese, but also helping keep the aging space at a steady level of humidity. Not unlike the natural stone walls and bricks of the pre-modern aging space. Wood shelves used in aging room also take on the same family of fantastically helpful microflora – yeasts, molds, and especially bacteria – that help create distinctive, out-of-this-world cheeses. The usefulness of these microbes has not only to do with flavor, but also with the final safety of the cheese.
Given what I have just told you about how awesome wood shelving is, why isn’t everyone using it? (At least 60% of American Cheese Society cheesemaker members do) Or at least trying to use it? First it is, not surprisingly, highly discouraged thanks to the stance of our federal friends. Second, the knowledge of how to properly care for wood is tucked away in the minds of a few and only a smattering of books and papers. Third many make only fresh cheeses where aging is not used. And finally, it is more work. More work is not what most cheesemakers need or can even contemplate. Let me tell you about our experience with wood shelves in our own aging room.
Wood Shelves at Pholia Farm
A few years ago we got permission from our inspectors to use wood shelves as long as we consulted with Dr. Lisbeth Goddik,Oregon State University’s Dairy Extension Specialist – a darned amazing woman. She suggested routine cleaning of the shelves with mild soap and warm water, then after rinsing with plain water either wiping the boards down with vinegar or a lactic acid bacteria wash. We did both. We marked which side of each shelf was treated with vinegar and which with bacteria. After aging the cheeses for many months, and before selling them, we swabbed the shelves and sent samples of the cheese to Agrimark lab. All results, for cheese and shelves, whether vinegar or lactic acid bacteria washed, were free from pathogens. So why did we stop? Ironically enough it was another aging room reality that is on the FDA’s hit list (not recent hits list…) cheese mites. I won’t go into too much detail about these little buggers (see one of my most popular posts for all of the itchy details), but what is pertinent is that the dark underside of the cheese sitting on the board was very desirable real estate for the mites. This required more frequent cheese rind labor, something that we were not prepared to do at that time. But I am now.
So Why the Ruling?
Consider for a moment that the FDA is tasked with an enormous responsibility. As that responsibility grows and food systems expand it becomes more expeditious to simplify. This means generalized rules that apply to everyone – versus thoughtful, logical exceptions. Think about it, before a couple of decades ago, you would be hard pressed (like one of those fabulous wood aged European Comtes) to find any US made cheese that was aged in a cellar type situation with a natural rind. Consequently the paradigm for aging became a squeaky clean walk in cooler. The regulations that developed reflected that reality. With the looming burden of the Food Safety Modernization Act, it’s not surprising that they are now seeking to streamline and enforce existing regulations, rather than allow states to take the responsibility of allowing exceptions.
As we move forward as cheesemakers, I think we need to nurture a new paradigm, one in which the aging room is not treated as a processing room, but as a separate type of space in which a different set of GMP’s apply. When I was at a cheese science conference in England, it was repeatedly said that “The dairy/cheese plant is NOT A HOSPITAL”, nothing could be more true in a room in which you are counting on microbes to flourish.
What Can We Do?
I am a member of the American Cheese Society’s Regulatory and Academic committee. This morning (June 10th) we finalized the press release and position of the largest body of cheese professionals in the United States. (See the document at: http://www.cheesesociety.org/wp-content/uploads/2014/06/ACS-Statement-on-Safety-of-Aging-Cheese-on-Wood.pdf )
So support ACS (join if you are not a member), contact your state representatives, let the FDA know how you feel, and most importantly keep buying and making great cheese! Now, I am going to go put those beautiful Pacific maple shelves back in the aging room. Watch out cheese mites, I’m watching you!
The best overall summary of the topic: Donnelly, Catherine, Cheese and Microbes (2014), American Society for Microbiologists, 171-174
Ak, N. O., Cliver, D. O., & Kasparl, C. W. (1994). Decontamination of Plastic and Wooden Cutting Boards for Kitchen Use. Journal of Food Production, 57, 23–30.
Guillier, L., Stahl, V., Hezard, B., Notz, E., & Briandet, R. (2008). Modelling the competitive growth between Listeria monocytogenes and biofilm microflora of smear cheese wooden shelves. International Journal of Food Microbiology, 128, 51–57.
Mariani, C., Briandet, R., Chamba, J.-F., Notz, E., Carnet-Pantiez, A., Eyoug, R. N., & Oulahal, N. (2007). Biofilm ecology of wooden shelves used in ripening the French raw milk smear cheese Reblochon de Savoie. Journal of Dairy Science, 90, 1653–1661.
Mariani, C., Oulahal, N., Chamba, J.-F., Dubois-Brissonnet, F., Notz, E., & Briandet, R. (2011). Inhibition of Listeria monocytogenes by resident biofilms present on wooden shelves used for cheese ripening. Food Control.
Nese, AK, Cliver, Dean, Kaspar, C. (1994). Cutting Boards of Plastic and Wood Contaminated Experimentally with Bacteria. Journal of Food Protection, 57(1), 16–22.
Oulahal, N., Adt, I., Mariani, C., Carnet-Pantiez, A., Notz, E., & Degraeve, P. (2009). Examination of wooden shelves used in the ripening of a raw milk smear cheese by FTIR spectroscopy. Food Control.
Schvartzman, M. S., Maffre, A., Tenenhaus-Aziza, F., Sanaa, M., Butler, F., & Jordan, K. (2011). Modelling the fate of Listeria monocytogenes during manufacture and ripening of smeared cheese made with pasteurised or raw milk. International Journal of Food Microbiology, 145 Suppl 1, S31–S38.
Zangerl, P., Matlschweiger, C., Dillinger, K., & Eliskases-Lechner, F. (2010). Survival of Listeria monocytogenes after cleaning and sanitation of wooden shelves used for cheese ripening. European Journal of Wood and Wood Products, 68(4), 415–419.