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June 13, 2011 at 1:44 pm #1252
I’d like to better understand the nature of the health risks of Home Dry Aging. Best I can tell several factors make home refrigerator dry aging more problematic than commercial dry aging: Temperature swings, humidity and meat surface moisture swings, and airborne contamination from other foodstuffs.
Of course yeast and bacteria normally and naturally exist and multiply on the surface of the meat over the course of dry aging including very long runs. My question is what differs between these cases and a case where the dry aging produces harmful toxins or bacteria. If the conditions outside of a certain envelope favor pathogenic organisms over benign ones, is there a source that details that?
Thanks.June 14, 2011 at 3:48 am #4781TheaKeymaster
Let me address your concerns first by saying that there is a need to have some clarification of terms and assumptions. You say: “I’d like to better understand the nature of the health risks of Home Dry Aging.” Are you referring to open air aging? UMAi DrybagSteak dry aging? Aging in a modern fridge? Or in a dorm fridge or a “beer fridge”? With cheesecloth or towels or bare? There are many ways that people conduct Home Dry Aging.
By the same token, having visited over a dozen commercial dry aging facilities, I can assure you there is a gold standard and there is reality. To assume that the gold standard has been applied to all commercial produced dry aged meat is unwise and incorrect.
The very few state-of-the art dry aging rooms are models of sanitized, controlled conditions–and they require such tremendous capital expense and maintenance, that the majority of commercial operations are “dry aging” is rather less than “optimally” controlled conditions. Often the “dry aging process” putting a subprimal a steel cooking tray on a rack merely draped in plastic to “age” in refrigerated warehouse space along side cardboard boxes of “wet-aging” meat in storage. Alternately, it is not uncommon to find meat resting on wire racks in a little used refrigerated cutting room along side cardboard boxes of finished product with people coming in and out of the room to pick up or drop off product. It may also be hung or racked in a refrigerated room and allowed to dry, occasionally with benefit of fans, but only aged for ten days, the minimum to qualify as “dry aged.” If you were to look into the process of commercial dry aging, your assumption of safety would certainly be shaken.
I would be very interested to understand where you gain your information for the impression that “Best I can tell several factors make home refrigerator dry aging more problematic than commercial dry aging.” While indeed, “temperature swings, humidity and meat surface moisture swings, and airborne contamination from other foodstuffs” pose potential risks, all but the rare specialized commercial dry aging operation experiences exactly the same swings and potential contamination challenges, not to mention flavor-impacting environmental influences.
While you are also right in your observation that “Of course yeast and bacteria normally and naturally exist and multiply on the surface of the meat over the course of dry aging including very long runs,” it is important to remember that like any cultured food (cheese, wine, fermented products like sauerkraut, yogurt and miso) the resulting flavors are often found desirable. What we assure you of with appropriately applied UMAi DrybagSteak is that outside flavors and the surface “funk” will be reduced or eliminated.
Your question as to is what differs between these cases of acceptable “culturing” and a case where the dry aging produces harmful toxins or bacteria is best answered by what the scientists who have studied our material have told us again and again–trust your nose. Bad meat is readily recognized by the human nose.
With proper storage temperatures (as in, those safe to store milk), regular circulation of air within the refrigerated environment and proper clean handing of the meat prior and during the aging time frame, pathogens are not a concern. Of course, this all assumes aging of fresh, whole muscle meat that has not been punctured, rolled, cut or in any other way had potential pathogens introduced within the meat.
It is also important to recognize that the meat still needs to be trimmed and cooked at appropriate temperatures to kill an potential surface pathogens.
Furthermore in answer to your question, “If the conditions outside of a certain envelope favor pathogenic organisms over benign ones, is there a source that details that?”, please refer to the research referenced on the UMAi DrybagSteak website Press page for two of the three published studies comparing dry aging traditionally with dry aging using UMAi DrybagSteak technology. Because the material is readily oxygen permeable, the anaerobic bacteria which pose the most likely pathogenic risk do not populate the surface of the meat with either method.
In closing, we would like to remind readers that we have seen too often that “commercial” processes are not a guarantee of food safety. Good practice is the same everywhere–and you can most assuredly safely, prudently create a dry aging environment in your home refrigerator where risk can be effectively mitigated. We offer UMAi DrybagSteak technology as an assist to accomplish this with greater ease and assurance.June 14, 2011 at 2:57 pm #4782
Thanks for your reply.quote :
Ideally all of the above as it would be great to better understand all the differences among all those different conditions, but I know that little if any testing has been done, so I’d be happy with whatever is known about any home-aging setup vs. a “commercial” dry age.quote :
I get your point that you’ve observed real-world commercial dry aging to be scarily haphazard. I’ll rephrase my question to ask about home dry aging vs gold-standard dry aging, i.e. carefully, correctly, and professionally done dry aging with all the right equipment and controls.quote :
Observation and common sense to me that a home fridge is not a well-controlled environment. For example, I’ve measured the temp swings in my home fridge using a scientific thermometer. It takes ~3 minutes to recover back to <38F on the bottom shelf of my normally loaded (decent thermal mass) residential fridge. Assuming ~6 opens per day that's ~20 minutes a day that dry aging meat is exposed to temps >38F. Typical fresh food and meats spoil or are thrown out after a week but meat undergoing a 21 day dry age would encounter ~400 minutes at temps >38F. I’m curious if that presents any additional risks versus a carefully controlled aging environment with uninterrupted <38F temps.
Similar situation with humidity/surface moisture as in the winter where I live it's dry as a bone but in the summer there is high ambient humidity that produces a light fog of condensation on my internal fridge surfaces when I open the door.quote :
The implication here is that these swings are not causing any detected health problems in the marketplace. Which is somewhat reassuring and good to know. But less reassuring than a study of what the safe parameters for dry aging actually are. I realize that probably hasn’t been done by the FDA or anyone else, unfortunately!quote :
Sorry, but this is misleading and dangerous. Pathenogenic organisms and their associated toxins are odorless and tasteless. It is true that a foul odor is a good sign the conditions have gone far enough outside safe parameters that all kinds of unwanted organisms are growing, but the reverse is not true, that a lack of foul odor indicates no pathogenic organisms are growing
I have read the two papers linked on the site and I appreciate the information they do provide but they are clearly focused on comparing bagged dry aging vs. open air dry aging in terms of moisture loss and taste difference. They don’t address what the safe environmental parameters of dry aging are. I’m very eager to read any studies that do, given that commonly practiced dry aging parameters are outside typical food safety norms along several dimensions, in my mind raising the risk of problems if just one other dimension goes awry.June 15, 2011 at 2:04 am #4783TheaKeymaster
You are correct on all counts:
1) There are no studies that we have seen comparing home dry aging with gold standard dry aging.
2) A home fridge does have the potential widely ranging temperature fluctuations.
3) We have no data to share with you comparing the surface microbacterial environment of dry aging meat with and without temperature fluctuations.
4) And, yes, dangerous pathogens may indeed be without scent. We are simply sharing the advice we were offered by the meat scientists when we asked, “How would someone at home know if the meat is spoiled?”
We are sorry we do not have the research that you seek comparing various styles of home dry aging with model commercial dry aging, but hope that this response provides some answers.
What we offer is a product that, when applied as directed, has been demonstrated to protect the surface of the meat from environmental contamination, and avoid creating an anaerobic environment within the sealed environment (in which the most lethal of pathogens can develop).
With any dry aging, it is essential to bear in mind the following best practices:
1) Optimal temperatures consistently do not range outside of 32-38 degrees.
2) 100% of the surface of the meat exposed to air within the refrigerated environment.
3) Excellent air flow is maintained in a modern, frost free refrigerator.
4) Only whole muscle meat is used, never punctured, rolled or handled in any way that will introduce additional bacteria to the surface or interior of the meat before applying UMAi DrybagSteak.
5) Post dry aging trim is thorough and not consumed.
6) Cooking of the meat is done as indicated by public health guidelines–the surface is exposed to high heat and the internal temperature reaches 165 degrees Fahrenheit.
Dry aging at home can be done with minimal risk if all these guidelines are followed. UMAi DrybagSteak allows you to accomplish this in a clean, sealed environment.June 18, 2011 at 1:43 pm #4794
Thanks for your candor and the helpful best practice summary.
I’m bemused that such a huge effort is made by agriculture, food science, and regulatory agencies to study and manage time, temperature, and contamination conditions of common beef production while production conditions for beef that sits around rotting for a month are ignored and left to haphazardly implemented, anecdotal practices
Given 1% of the beef supply is dry aged with millions of people eating it, I’d have expected at least some scientific study of what constitutes safe dry-aging.
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