Lessons Learned: A New Era for Meat and Poultry Safety

By Kimberly J. Decker, Contributing Editor

When a shark attacks a swimmer off the coast of a popular beach, it grabs headlines because its scaryand rare. You could say the same for high-profile foodborne illness outbreaks linked to contaminated meat and poultry. While memories of the tragic deaths traced to E. coli O157:H7-tainted hamburgers in the early 1990s remain vivid, they do so less as a herald of whats to come than as a turning point for the industry.

If you think from a meat-safety standpoint about where we were in the 1990s," says Betsy Booren, Ph.D., director, scientific affairs, American Meat Institute Foundation (AMI), Washington, DC, we had very large recalls in beef. And that changed everything. We also had recalls of ready-to-eat products in the late 90s, and that was a game-changer."

But thanks to a changed culture of thought" that embraces everything from intra-industry cooperation to stepped-up safety practices and a continually improving toolkit, the meat and poultry industry is not the same as it was in the early 80s or late 90s," Booren says. Were not even the same industry we were five years ago. Weve grown up. Weve changed. And as we talk about safety as a whole, many other food categories are looking to us as a leader."

A changed landscape

The numbers bear her out. Although the  Centers for Disease Control and Prevention (CDC), Atlanta, estimated the incidence of foodborne disease in 2011 at approximately 48 million casesresulting in about 127,000 hospitalizations and as many as 3,030 deathsthat figure includes many pathogens and foods, not just meat and poultry," says Matthew Taylor, Ph.D., assistant professor, meat science, Texas A&M University, College Station, TX.

More telling, the 2011 tally represents a considerable drop from CDCs last major estimate of 1999. As Taylor points out, the CDC/FDA program FoodNet, which collects data from multiple states sentinel sites across the United States, reported that the incidences of foodborne disease from pathogens like E. coli O157:H7, Salmonella, Listeria monocytogenes, and even Campylobacter, have declined" since the period from 1996 to 1998.

This is great news for carnivores. I dont think weve ever had safer meat and poultry than we do now," Booren says, which is interesting if you think about the stories we see in the media." But perhaps those stories persist largely because so many media outlets can now sustain them. One consumer of a bad bologna sandwich can tweet his way to a guest spot on a talk show, and we all know what happens when a telegenic chef joins forces with mommy bloggers to impugn a perfectly safe and efficient method for separating lean beef from fat that ensures a dearth of pathogens in the product. (That would be lean finely textured beef, or, less charitably, pink slime.")

Catch as catch can

But the fact is, recalls are down and safety is up. Booren notes that almost 10 years have passed since the last recall of ready-to-eat meat products linked to listeriosis. That doesnt mean recalls arent occurring; earlier this year, Buona Vita, Inc., Bridgeton, NJ, recalled almost 325,000 pounds of frozen RTE meat and poultry products that tested positive for Listeria. But as of early July, USDAs Food Safety and Inspection Service (FSIS) had reported no illnesses associated with them.

Catching contaminated product before it makes people sick may be the key safety backstop for industry to keep in reserve, because no matter how diligent our sanitation or how advanced our hurdle technologies, contamination of meat and poultry will happen. Meat and poultry are just too appealing to microbes.

Microbes like" meat and poultry for much the same reason we make the foods part of our balanced diets, Taylor says. Theyre rich in nutrients like protein and minerals," which microorganisms need to build proteins and amino acids of their own. Meat can also serve as a source of water to microorganisms that can extract water molecules from the protein structure in meat," he says.

The usual suspects

Among the microorganisms of concern are the usual headline-grabbers, but their persistence underscores the arms-race nature of meat and poultry safety. Take E. coli O157:H7. Its no stranger to industry or to the beef and dairy cattle whose gastrointestinal tracts it calls home. But complicating matters is the realization that some Shiga toxin-producing E. coli (STEC) can cause human foodborne disease with symptoms similar to that of E. coli O157:H7," Taylor says. As such, some STEC that have been identified by the CDC as being causative of a large proportion of the non-O157 STEC-derived foodborne disease have been named as adulterants in raw non-intact beef products by the USDA."

Swine and poultry are associated with Salmonella and Campylobacter, though why this is so is, to my knowledge, not fully elucidated," Taylor says. In any case, a current area of interest is Salmonellas ability to withstand processing procedures designed to control Listeria monocytogenes in RTE foods. The American Meat Institute Foundation has in its recent call for research proposals asked for proposals that investigate the efficacy of antilisterial process interventions for the inhibition of Salmonella on RTE products," he notes.

Listeria is notorious for contaminating RTE meats that consumers rarely subject to a kill step, such as lunchmeat. It is a post-processing, post-lethality contaminant," Booren says. So, if you open a package of ready-to-eat meat, cross-contaminate it and put it in your refrigerator, Listeria will grow."

Mani Badvela, principal scientist, Kemin Industries, Des Moines, IA, adds that Listeria also resists salt and acidity and does not change the taste or smell of the food product, leaving it difficult for the consumer to detect." Yet, an increase in Listeria greater than one log in RTE deli meats is considered unacceptable," he says. In late 2003, USDA-FSIS  implemented a ruling (Title 9 of the Code of Federal Regulations (CFR), Part  430) requiring manufacturers to take precautionary steps to better control product adulteration from L. monocytogenes. The regulation allows for the use of approved antimicrobials."

As far as emerging threats go, meat scientists are studying the potential foodborne disease risk of methicillin-resistant Staphylococcus aureus (MRSA) in pork. Taylor notes that James Dickson at Iowa State University, Ames, IA, is working to understand the pathogens transmission in the pork harvest environment, as well as its cook tolerance.

At this point," Taylor says, it does not appear as though the pathogen is any more tolerant to proper cooking than other forms of Staphylococcus aureus that are more common contaminants in foods." But inquiring minds will stay in the know.

Safer harbors

These pathogens appear in a variety of meat and poultry under a variety of conditions, but weve learned that some product formats harbor more microbes than others. Contrast ground meat with steaks, for instance. The muscle in a live, healthy cow, Taylor points out, is sterile. And even though a butchering knife may not be, when we cut this meat off the carcass, our knives dont penetrate the great majority of muscle/meat, so contaminating microorganisms dont find their way into deep tissues." And though knives may drag pathogens across a steaks surface, that same surface gets a blast of bug-killing heat during the cooking process.

In comparison, ground products may have pathogens spread throughout the product," Taylor continues, which is a big reason" why he doesnt recommend ordering burgers rare. But a similar risk can attend steaks subjected to mechanical tenderization or enhancement with needle injection, which have triggered disease outbreaks of their own. Thus, to minimize risks, he says, a process facility should implement appropriate procedures to maintain facility sanitation and prevent cross-contamination during processing."

Meat and poultry, by their nature, may be a microbes dream buffet, but the most critical point that should be made," Taylor says, is that most cases of foodborne disease are not the result of the ability of meat and poultry to support microbial growth." Ultimately, he says, the riskiest meat product is the one thats not handled properly but is abusively stored, handled or undercooked, allowing pathogens to be transmitted to the consumer."

Intervention time

With that in mind the meat and poultry industry has built a prevention infrastructure comprising both cutting-edge technologies and time-tested methods. We still use those basic, fundamental meat-processing principles," Booren says. Its just that now we understandand controlthem better.

While rigorous sanitation and handling standards are essential to keeping fresh meat and poultry safe, Taylor notes that safety improvements weve seen in many processed products stem from three types of approaches: physical processing (as in the heat applied through smoking); antimicrobial action from fermentative cultures or direct organic-acid addition; and techniques like drying and salting to inhibit microbial access to nutrients and subsequent growth.

For some products, multiple processes are used, such as frankfurters that have steam applied to them, and then an antimicrobial application to prevent L. monocytogenes from growing on product surfaces during post-process storage," Taylor says.

Kerri Harris, Ph.D., associate professor of meat science, Texas A&M, and director, International HACCP Alliance, College Station, TX, says establishments often implement multiple interventions throughout the process, and research has shown that a multiple-hurdle approach may result in greater reductions of bacteria." However, she stresses, quality still trumps quantity here: It would be better to have one effective intervention than it would to have three ineffective interventions."

Lets consider several of these interventions in turn.

Salts and brines. A preservation technology almost as old as mankind, the application of salt is still useful in curing and preserving some meat products. But salting technology has advanced well beyond NaCl to include phosphates and other brining ingredients that, in some cases, display antimicrobial activity.

But salts and brines arent guaranteed fail-safes for pathogen control in all meat products; rather, in processed items with low pathogen counts, brines with added salts may help prevent pathogen growth. Researchers at the Colorado State University Center for Meat Safety and Quality are at work demonstrating the effectiveness of salting and brining.

Nitrates and nitrites.  Nitrates and nitrites remain in our processing arsenal because they help stabilize the pink color and appealing flavor we expect in cured meats. But they can also inhibit spores of Clostridium, a potential foodborne pathogen and problematic spoilage organism. Using nitrates and nitrites involves some controversy, though, as nitrate-cured meats cooked to high temperatures can see the formation of carcinogenic nitrosamines. (The United States thus limits the allowable concentration of nitrates and nitrites to 200 ppm or lower.)

Nevertheless, nitrites and nitrates remain useful preservatives in the right products. And, while celery extract and compounds like sorbic acid can replace some of the nitrite content, it may be some time before they replace traditional nitrite salts in cured-meat formulation entirely.

Organic acids. Washes of organic acids, often in conjunction with hot water, provide an early intervention at the point of carcass harvest. They work by disturbing something called the proton motive force, which, Taylor explains, is an essential component of microbial energy creation and use." They can also degrade microbial DNA or disrupt bacterial cells lipid membranes.

Organic acids, Taylor says, are powerful antimicrobialsa big reason theyre used in multiple food processes, as well as in some sanitizers and meat-surface decontaminants."

Badvela notes that, among organic acids, lactates have historically been the only option for controlling Listeria in RTE meat and poultry." Yet they havent always proven optimally effective. He says that any organic acids potency against microbial growth depends on the amount of undissociated acid which penetrates the bacteria cell wall and disrupts its physiology." His company filed a petition in April 2010 to allow the use of propionic acid and sodium propionate as antimicrobials in RTE products, and were awaiting a letter of no objection for the addition of these products to 9 CFR 424.21," he says

Smoke compounds. The discovery that cooking over a wood fire could protect meat from spoilage was a watershed moment in human development. By the early 1900s, says Robert Johnson, value optimization manager, Red Arrow Products Co., Manitowoc, WI, the bactericidal properties of wood smoke were among the first reported in a technical publication. Since then, numerous studies have reported the bacteriostatic or bactericidal effects of smoke in a variety of meats and fishes"and against a variety of organisms, from E. coli and Clostridium botulinum to Listeria, Staphylococcus species and Pseudomonas aeruginosa.

The mode of action appears to involve acetic acid, a naturally occurring smoke component, which suppresses microbial growth. Furthermore, the carbonyl fraction, rich with certain aldehydes, also has a definite antimicrobial activity. Factors of importance are the concentration, pH and contact time with the product surface," Johnson says.

He notes that a number of processors are manufacturing meat logs in barrier films with an inner coating of condensed natural smoke that transfers onto the product surface. These logs, after thermal processing, are typically stored in a cooler," he explains. The surface of the casing is rinsed with a solution that would be detrimental to the survival of any bacteria transferred to the casing during handling or transport to the slicing floor, and the barrier film is removed after this decontamination rinse and the product is either crust-frozen or transferred directly to a slicer for packaging." The benefit? The processing and packaging scheme reduces a products exposure to potential contamination by disease-causing agents. In comparison to previous generations of permeable casings the total time the product is exposed is quite short," Johnson says.

Plant-derived compounds. Taylor notes that plant-based compounds have grown popular with researchers investigating their potential antimicrobial activity against meat and poultry pathogens. Extracts of garlic, onion and spices such as clove, thyme, sage, oregano and others are particularly potent antimicrobials," he says. The compounds work by various means, including suppressing the production of virulence and pathogenesis compounds such as toxins," he continues, and by binding nutrients, like iron, that bacteria need to grow.

Some extracts can also destabilize a microbes outer membrane, rupturing the cell and letting its internal contents leak out," Taylor says. One example is a formulation based on hydroxytyrosol, the smallest and most active of all olive polyphenols," says Paolo Pontoniere, vice president, corporate communications, CreAgri, Hayward, CA, the products manufacturer. The formulation creates a crosslink with the bacterial membrane that triggers cell-wall dissolution in a process similar to lysing," Pontoniere says.

Testing by FDA and the University of Arizona, Tucson, AZ, has shown the product to be extremely effective" against Staph A, Enterotoxin A, Salmonella and Listeria at application levels ranging from 300 ppm to 5,000 ppm, Pontoniere says. And, in a move that should please fans of both clean labels and safe meat and poultry products, he says, We kept it organic, GRAS-certified and derived from the juice of olives via hydrolysis, rather than using solvents or other synthetic compounds."

Emerging interventions. Researchers at universities and private firms are writing the next chapter of meat and poultry safety, and the themes theyre developing are compelling. Taylors lab is applying encapsulation technologies to antimicrobials to provide a longer-lasting antimicrobial impact in food," he says. Others around the world and United States have also been exploring this type of research with good results, though application in meats is somewhat limited as compared to other foods like dairy and produce."

And, though biocontrol strategies" may sound like a weapon in a sci-fi flick, theyre far more benign than that (unless youre a bacterium), involving the use of competitive bacterial cultures, bacteriophages and metabolites of fermentative cultures as a source of antimicrobial activity," Taylor says. For consumers or processors wishing to operate in the organic foods industry, or produce natural products, these represent potential options."

Especially intriguing are the bacteriophages, bacteria-killing viruses. These viruses have recently begun to gain approval by the FDA and USDA for application to meat and poultry surfaces to kill bacterial pathogens, such as Listeria monocytogenes, E. coli and Salmonella," Taylor says. Researchers at the recently established Texas A&M University Center for Phage Technology aim to explore their biology, genetics, physiology and interactions with host bacteria, he says.

Brave new world

Its heady stuff for us food-safety geeks, but hurdles remain. Taylor notes that some antimicrobials are very specific for the pathogens they inhibit or inactivate, and thus cannot be applied broadly to inhibit multiple projects. For example, bacteriophages are very specific for the bacteria they attack; Listeria-killing phages are generally ineffective against E. coli," he says. "This is not a weakness on the part of the phages, but a simple result of their physiology."

And the same holds for some bacteriocins, compounds that bacteria produce to inhibit the growth of other bacteria. Nisin, for exampleproduced by Lactococcus lactis and approved for use in meat preservationworks well against Listeria species and Clostridium, but its no match for Salmonella or E. coli, Taylor says, except at very high concentrations or in combination with other ingredients."

But the more we learn, the more well sharpen our meat and poultry safety chops. And the less likely well be to have to learn the hard way. Outbreaks of listeriosis, campylobacteriosis and salmonellosis in various meat and poultry dishes have taught us the importance of strong sanitation programs, the prevalence of the pathogen in animal production environments, the need for full cooking and the ability of pathogens to contaminate multiple meat and poultry foodstuffs," Taylor says.

But not all food safety improvements need be a response to a disease outbreak.  Many saw the need to be proactive and preventative of risks, rather than always trying to be responsive to outbreaks," Taylor says. While not all lessons are easily learned, and some come at great costs, the meat and poultry industries have actively updated their practices with new information as it has become available."

Kimberly J. Decker, a California-based technical writer, has a B.S. in consumer food science with a minor in English from the University of California, Davis. She lives in the San Francisco Bay Area, where she enjoys eating and writing about food. You can reach her at [email protected].