Nasser Karimzadeh, P.E.
December 6, 2017
My company, National Engineers Inc., provides engineering services and continuously seeks solutions to mitigate food contamination and improve pathogen control in the meat and poultry industries. We recently evaluated the technology offered by airPHX Environmental that uses a unique spectrum of Reactive Oxygen Species (ROS) to eliminate airborne and surface pathogens. Our evaluation included independent lab testing to confirm effectiveness and field testing in a commercial poultry processing plant. We then evaluated options for deployment of this technology in the meat and poultry industries.
THE PATHOGEN PROBLEM
Antimicrobial resistant pathogens such as Escherichia coli O157:H7, Salmonella spp and Listeria monocytogenes pose an ongoing and increasing challenge for the food safety professionals, particularly in the meat and poultry industries. E. coli bacteria lives in the intestine of animals and it is transferred from intestine to meat during slathering of cattle or evisceration of poultry. E. coli can be easily transferred from an infected animal to another by contact during the harvesting process. E. coli can cause severe, bloody diarrhea and abdominal cramps, followed by serious organ system damage such as kidney failure. According to Fortune Magazine (article published on May 6, 2016), “Bacteria Contamination cost the American Food Industry over $55.5 billion in recall, litigation, settlements and associated safety problems. Most cases of food-borne illness are sporadic, meaning they cannot be traced to a specific “outbreak”—an event known to have caused illness in others. Even in the case of an outbreak, it is very difficult to identify those who fall ill. For example, out of every 29 people who get sick from a typical salmonella outbreak, the CDC estimates that just one will be formally diagnosed. Existing methods to address this challenge have included thermal pasteurization, organic acid application (lactic, acetic, and Inspexx), and ozone technology. For example, a common practice in the beef packing industry is the treatment of hot beef carcasses with up to 5% lactic acid. Lactic acid attacks non-stainless-steel metals severely. We are presently working on multiple projects in the beef industry to replace refrigeration evaporators in the cooling rooms that have been damaged by lactic acid. Additionally, lactic acid can negatively impact waste treatment operations by killing the useful bacteria in the waste treatment facility and increasing both fresh water usage and waste water. Thus, the pathogen control methods all have limitations and can have adverse effects in product and plant operations and can likewise increase the cost of processing operations.
airPHX uses “atmospheric cold plasma” to generate its ROS. Pathogens are eliminated in a two-step process: (1) any airborne organisms are oxidized immediately by the ROS as they pass through a reaction chamber; and (2) a small amount of ROS molecules are distributed into the environment and oxidize airborne and surface pathogens in the treatment space. The airPHX ROS species are very reactive to carbon based molecules and continuously destroy bacteria, mold, viruses and other VOCs “non-selectively”. The airPHX ROS eliminates pathogens on the proteins themselves, as well as equipment, HVAC coils, ductwork, walls and floors within the environment. Because the plasma can be created at varying external temperatures and relative humidity, and from ambient air, the airPHX technology can be deployed in a wide variety of environments.
IMPACT ON PATHOGENS
airPHX’s ROS is effective because it ruptures the cell wall of the pathogens themselves. This method is more efficient than chlorine, lactic acid or other antimicrobials, which depend upon diffusion into the cell protoplasm and inactivation of the enzymes. Because the cells themselves are destroyed in this process, there is no opportunity for pathogens to mutate or develop resistance to the treatment.
In our evaluation of the airPHX technology, we evaluated lab testing by Dr. Rick Falkenberg, Ph.D. CFA, Scientific Air Solutions, Turlock, California. In a series of tests in 2017, Dr. Falkenberg evaluated the effectiveness of airPHX’s ROS in eliminating a variety of food based pathogens on surfaces. Key points include: (a) testing was performed on stainless steel, plastic and linoleum coupons inoculated with the actual organisms; (b) organisms evaluated included 30 bacteria, viruses and protozoa including the most common pathogens in food processing: Escherichia coli O157:H7, Salmonella spp and Listeria monocytogenes; and (c) the coupons treated with airPHX generated ROS realized an approximate 4-log reduction in organisms in 30 minutes (from 10,000 organisms to 1) and effectively a total kill after four hours. See below for E.Coli O157:h7 testing summary:
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