Is Green Meat Safe to Eat?
~ By Snowden Bishop ~
The Centers for Disease Control and Prevention (CDC) estimates that each year, more than 48 million Americans, one out of every six people, become ill as a result of ingesting food-borne pathogens (bacteria, viruses and microbes) such as such as Salmonella, Toxoplasma, Listeria, Norovirus and Escherichia-coli O157:H7 (E-coli). Of those, hundreds of thousands are hospitalized, and more than 3,000 people die. While a number of recent outbreaks to make headlines have been linked to contaminated fruits and vegetables, most incidences of food-borne illness, including those sourced to fruits and vegetables, are traced to wild animals, livestock production or contaminated meat.
Salmonella and E-coli have become household words since outbreaks at high-profile places like Jack-in-the-Box and Costco made national headlines. Most commonly referred to as “food poisoning,” these pathogens cause serious digestive illness, especially among young children, elders and those with compromised immune systems. According to Dr. Keith Belk, Associate Professor of Animal Sciences at Colorado State University, E-coli bacteria are responsible for 176,000 illnesses, 3700 hospitalizations, and 20 deaths annually in the United States. They can be transmitted easily by ingesting contaminated food, but they are also passed along through personal contact with infected surfaces or by shaking hands with someone who has come in contact with infected surfaces. Most people can prevent exposure to these pathogens by thoroughly washing hands and food preparation surfaces with soap and water, and by thoroughly cooking poultry and meat.
Despite efforts to minimize exposure, anyone can unknowingly come into contact with undercooked meat, contaminated fruit or under-washed vegetables. Contamination is often attributed to food preparation at home. At room temperature, kitchen counters and cutting boards used for preparing raw meat and poultry provide ideal breeding conditions for deadly pathogens. Following proper food preparation and storage guidelines such as cooking meat thoroughly, promptly chilling leftovers and keeping kitchen and lavatory surfaces clean will minimize chances that bacteria can spread.
However recent outbreaks have been linked to the food production process, and more often than not, have been traced to some form of animal contamination such as exposure to animal waste.
One of the most deadly outbreaks originated in a batch of cantaloupe — the contamination was traced to its packaging origins. The fruit had been processed in areas that had been exposed to animal waste, processed on equipment that was not sterile and stored and packaged in temperate conditions that hastened the decomposition process and expedited the bacterial multiplication process. The outbreak resulted in 13 deaths and the massive recall of these fruits cost millions of dollars. Despite assurances that precautions would prevent a recurrence, what remained was faltering consumer confidence that such an outbreak could be prevented in the future.
The residual confusion has raised questions. If an outbreak of e-coli in fruit was traced back to animal contamination, then what warrants confidence that meat can ever be trusted? The organic food movement and growing interest in chemical and additive-free food sources leads to other safety concerns, especially when it comes to organically produced beef. Is green meat safe to eat? At what level must consumers sacrifice food purity to ensure safety?
According to a 2010 dissertation study (“Zurich study”) conducted by a doctoral candidate at the University of Zurich titled, Antibacterial Activity of Decontamination Treaments for Cattle Hides and Beef Carcases, a growing interest in organic food and meat produced without hormones, antibiotics and chemical microbiological intervention has raised concerns about potential increase in the presence of food-born pathogens of processed meat. The study examined numerous physical, chemical and biological intervention methods to ascertain effectiveness of each. Despite growing public interest in chemical free food production, the Zurich study’s foregone conclusion was, “Decontamination treatments always must be considered part of an integral food safety system.”
“The beef industry has been focused on dealing with E. coli O157:H7 since the 1993 Jack in the Box outbreak. Thus, beef contamination has been the subject of intense research and intervention development for nearly twenty years,” said Tommy Wheeler, of the USDA- Agricultural Research Service, U.S. Meat Animal Research Center, Clay Center, NE. “During that time, great progress has been made in minimizing pathogen contamination in beef products. A multi-hurdle approach has been implemented that includes numerous antimicrobial interventions at various stages of processing – because no one intervention is 100% effective – plus rigorous testing for pathogens.”
In a report on beef decontamination technologies circulated by the National Cattlemen’s Beef Association, Dr. Belk stated, “Such (multi-hurdle) systems improve regulatory compliance and enhance product safety, provided that processing and preparation for consumption are also performed using good hygiene practices.”
Regulatory efforts to minimize food-borne illnesses outlined in the Federal Food, Drug, and Cosmetic Act (FFDCA) include surveillance, testing, reporting and enforcement guidelines. The FDA Food Safety Modernization signed into law by President Obama in 2011 essentially amends the FFDCA with new, more rigorous guidelines in an effort to improve food safety, strengthen enforcement and broaden public transparency. These new guidelines apply higher standards for sanitation and protection against food adulteration, which can occur in food processing whether intentional or not. The meat industry as a whole must find a balance: apply decontamination methods that both minimize use of natural acids, cleansing agents, chemicals, and maximize effectiveness when it comes to eliminating harmful pathogens while avoiding food adulteration in the process.
Pathogens such as E-coli are naturally present in the intestines of cattle, and proliferate in their waste. Without immediate intervention, colonies of E-coli and other bacteria can grow rapidly as a natural part of the carcass decomposition process. Existing colonies can actually be spread when simple washing with cool or warm water occurs. Therefore, eliminating exposure to bacteria entirely is particularly challenging if not downright impossible. The main objective remains minimizing cross-contamination of the pathogen during the slaughter process, and then eliminating the pathogen via a decontamination process prior to sending the processed meat to market.
According to the Zurich study, the transfer of microorganisms from hides to carcass during the de-hiding process poses the greatest threat by sheer numbers common pathogen-transmitters such as fecal matter most often found in the animal’s hide prior to slaughter. “Cattle hides often show high bacterial loads and have been identified as a primary source of carcass contamination.”
To minimize exposure to E-coli, beef producers must first eliminate the primary source: contaminated hair. Two most common methods include chemical hair removal and washing carcasses with a combination of high-pressure water and antimicrobial compounds such as chlorine or phosphates. Once the carcass is washed then de-haired, additional decontamination continues throughout the entire production process. The Zurich study found that chemical de-hairing method was less effective than washing in preventing airborne bacterial transmission to carcasses during the process.
Once hide is removed, a series of interventions occur at nearly every phase of production.
Post slaughter, the most common method of meat decontamination used today involves spraying the meat with acids such as lactic acid or citric acid, which are known to kill bacteria, followed by washing away acid residue with water combined with an emollient which facilitates removal of acid and bacteria, then immediately chilling the meat to prevent any new bacteria from forming. While this method is approved by the USDA, and produces results that fall within guidelines generally recognized as safe (GRAS) by the USDA’s Food Safety Inspection Service, the process requires excessive water usage and expensive biological agents to be effective.
For some, “GRAS” is a loosely cast net. Agents such as lactic acid, citric acid and acetic acid are common in most processed forms of food, widely used as preservatives or flavorings, however, an overabundance of these stirs consternation about whether GRAS equates to “good for you.”
“The beef industry uses a combination of various antimicrobial interventions because they have different mechanisms of action and some work better than others on specific pathogens. This provides the maximum level of safety for the final meat products,” said Wheeler. “Just because a compound is called a ‘chemical’ does not mean it bad for you or toxic in some way. They are all natural compounds that are commonly found in the environment and many foods.”
Despite the fact that many of the chemicals used in meat decontamination processes are substances derived from nature, the public perception that their use in meat processing poses health concerns remains an issue. However, the bigger issue is dealing with pathogens that, if left untreated, would cause larger public health concerns.
One of the most effective interventions for killing bacteria is heat. Most common pathogens cannot survive boiling temperature.
According to Wheeler, hot water and steam pasteurization are the most commonly used heat interventions in the industry today. However, water hot enough to kill bacteria does cause what he calls denaturation, or cooking, of lean areas exposed to the heat. The method amounts to more waste because the “cooked” areas are trimmed off. This method does not fully eliminate the need for chemicals because once meat is sectioned or cut, high-pressure washing is both impractical and wasteful.
Citing research studies conducted in the early and mid 1990s under commercial conditions, the Zurich study reported that water alone was not nearly effective enough to eliminate pathogens, and rather, washing can actually spread bacteria on carcass surfaces. Commonly, the hot water and steam pasteurization methods are deemed most effective if followed by application of a chemical compound such as lactic acid, bromine, acidified sodium chlorite, or peroxyacetic acid. This process can be costly, according to Wheeler, who explained, “Keeping an adequate supply of hot water or steam is very expensive.”
And while public demand for a reduction in use of chemicals in food remains one concern, similarly, organic consumers might also be concerned with the environmental impact of excessive use of resources such as water, chemicals and electricity, as well as the entry of bacteria and/or chemicals into water waste streams.
Two more methods that minimize use of water are chilling and dry heat applications. Both of these were also addressed in the Zurich study, which concluded that dry heat poses some of the same disadvantages as hot water as it tends to desiccate the surface of the meat; and chilling without some organic acid intervention is may be effective for slowing contamination but not eliminating all pathogens. The study concluded that these methods were not as effective as hot water and chemical decontamination methods overall.
“Ironically, one of the most effective and safest antimicrobial treatments is electron beam irradiation,” said Wheeler. “This technology is one of the most researched but implemented only by a few ground beef producers because of the perception that consumers will not buy irradiated product.”
In the past, irradiation of food generally used gamma rays, which intervene with microbial activity via ionizing radiation that damaged DNA and generated free radicals. This method, like other heat decontamination methods, sufficiently denatured the surfaces of meat. New methods of irradiation using electron beams, on the other hand, have been effective in vastly reducing inoculated pathogens without affecting sensory characteristics of the meat. According to the Zurich study, electron beam radiation is twice as effective as any conventional washing or heating method of decontamination.
New technology involving use of the gyrotron beam, a high-frequency, microwave-based elecronic beam that “flash-heats” contaminants without denaturing the proteins of the meat, has recently been researched. According to Dr. Vlad Sklyar, inventor of gyrotron beam technology and President of Gyrotron Technology Inc., “The millimetric wavelength of the gyrotron beam makes it a more efficient heater of non-metallic materials including water, blood and fat. It is also more effective
Studies have concluded that gyroton method is as effective as electron beam irradiation and may be more palatable to health-conscious consumers because, according to Wheeler, it eliminates the radiation perception issues because it uses microwave technology, which has broad acceptance publicly. Furthermore, whereas ionizing irradiation (electron beam) requires product labeling, gyrotron beam decontamination does not.
For health-conscious and environmentally concerned consumers, the major advantage of this technology over traditional carcass decontamination methods lies in the reduction in chemical use, conservation of water and reduced generation of waste streams containing organic acids, chemical compounds and contaminated or denatured meat.
“We have conducted independent lab tests using the gyrotron beam. What we found is that, whereas in conventional methods of decontamination, one of 1,000 units of bacteria survive, with this method, less than one in 100,000 units of bacteria survive,” said Dr. Sklyar. “We also found that this method is not only more effective, it is far more efficient in terms of its expenditure of electricity, water and chemicals. Therefore, it could be considered a green technology and will ultimately be more sustainable for the agriculture industry.”
The USDA is looking further into gyrotron beam technology. Wheeler concludes, “Only limited preliminary data are available for the gyrotron so far, but we have applied for grant funding to evaluate it more extensively.”
The evaluation may eventually answer the question: Is Green Meat Safe to Eat?