Even though the US meat and poultry processing industry may produce the safest food in the world, there is a need to offer extra protection against microbial contamination, in particular by pathogens such as Escherichia coliform, Listeria monocytogenes and Salmonella. Pathogens were responsible for the 839 foodborne disease outbreaks reported in the US, in 2016, which resulted in 14,259 illnesses, 875 hospitalizations, 17 deaths and 18 food recalls, according to Centers for Disease Control and Prevention (C.D.C.), Atlanta. Mollusks, such as oysters and scallops, were the No. 1 food category associated with outbreak illnesses, followed by pork, which was responsible for 438 illnesses. Beef was responsible for three multi-state outbreaks, chicken for two.

With such outbreaks comes lots of food waste. The 22 pathogen-related meat and poultry recalls by the US Dept. of Agriculture in 2018 affected more than 17 million lbs. of product.

“Foodservice and retail buyers are looking for longer product shelf life, in part due to complex logistics and, essentially, a longer cold chain,” says Tom Rourke, business development director, Corbion, Lenexa, Kan. “Manufacturers want to maximize their geographic reach, but when they do, they not only expand their opportunities, they also increase the potential impact of an outbreak of foodborne illness.”

The costs of a recall in terms of dollars and brand image can be swift and severe. Food safety has become a critical success factor for meat processors.

“Processors should choose to manage hazards that are reasonably likely to occur with the easy addition of an ingredient that protects the product until consumed,” says Roger Maehler, senior director of seasoning research and development, Newly Weds Foods Inc., Chicago. “The products at highest risk will be those that are subject to the unreliable cold chain, with the longer the shelf life, the greater the risk. Other high-risk products are those prepared by consumers, with the greater the preparation, the higher the risk.”

Eliminating and preventing

Certain foodborne pathogens may be present on raw foods, with proper cooking and handling typically eliminating the potential for foodborne illness. But the possibility for contamination after cooking exists. This is a major concern with ready-to-eat (R.T.E.) meat products that do not undergo an additional lethal cooking step prior to consumption. They are particularly vulnerable to Listeria, which is omnipresent in the environment.

“The unique growth characteristics of Listeria, including its ability to survive freezing, tolerance to salt and heat, and capability to form biofilms, make it a challenging pathogen to control,” says Steve Campano, vice president for research and innovation, Hawkins Inc., Roseville, Minn. “While surveys have shown that prevalence of Listeria in RTE meats has decreased significantly – most certainly as a result of focused research, science-based regulations and industry efforts – the pathogen continues to contaminate these products at very low levels and illnesses continue to occur.”

Processed RTE meats that are pre-sliced, ground or diced, are the most susceptible to contamination. Lower-salt items, products with more water activity and those with higher pH are also vulnerable.

“The more a product comes in contact with any surface – whether hand, tool or machinery – the more opportunities there are for harmful bacteria to be introduced,” Rourke says.

Because pathogens do not typically change the taste or smell of the food, they go undetected. This makes it imperative that manufacturers of these products take all possible precautions to ensure food safety.

“Meat and poultry products contain many positive nutrients for humans, which also makes them ideal sources of nutrients for pathogens,” says Janice Johnson, food technical and application services lead, Cargill Salt, Minneapolis. “To combat pathogens, manufacturers include many ‘hurdles,’ such as heat treatments, pH modifications and water activity adjustments, in the processing of meat products, all with an eye toward preventing the exposure of pathogens to consumers.”

Table salt – sodium chloride – was one of the earliest ingredients used to preserve and prevent pathogen growth. It may be injected into whole muscle via a brine solution or blended in as a dry ingredient in processed meats.

“Salt decreases the water activity, or conversely, increases osmotic pressure, which creates an environment that is undesirable for pathogen and spoilage organism growth,” Johnson says.

An increase in osmotic pressure in the environment causes water to move through the cell membrane and out of microorganisms. Basically, this dehydrates the cell and it loses viability. “This partial dehydration severely interferes with the life cycle of the organism,” Johnson says. “Potassium chloride can have the same effect, as it also decreases the water activity of meat and poultry products.”

There are many other pathogen-inhibiting additives – natural and traditional chemical – available for adding an extra defense against potentially deadly microbes.

Organic acids and their salts

Organic acid salts are some of the most effective antimicrobial agents used in meat and poultry products. They are basically organic acids, such as propionic acid, acetic acid and citric acid, buffered, also known as neutralized, with a conjugate base. Their mode of action on pathogenic and spoilage microorganisms is the same, but their effectiveness varies by the organic acid, specifically the amount of undissociated or non-ionized acid.

“Lactic acid and acetic acid form the basis of the majority of our antimicrobials,” Campano says. “Lactic acid is a product of the fermentation of sugars, and acetic acid is the primary component of vinegar, which is produced by the acetous fermentation of dilute distilled alcohol.”

It is generally agreed that the ability of these organic acids to inhibit microbial growth is related to their ability to diffuse into the cytoplasm of bacterial cells.

“Once inside the cell, certain metabolic functions are inhibited, in part due to the acidification of the cytoplasm,” Campano says. “However, it’s not usually practical to add an acid to a processed meat product. The resulting pH decline and associated protein denaturation are not conducive to production of the typical hot dog or deli meat item. As a result, we typically buffer the pH of the organic acids to produce the associated salt at a near neutral pH, which has no detrimental effect on the production of the finished meat product.” 

Fermentation technology allows for the development of optimized-performance ingredients containing organic acids, sugars and peptides, oftentimes without any artificial additives. Vinegar-based ingredients are gaining traction among processors because of its clean-label appeal.

“It’s a simple, commonly recognized ingredient, and can prevent Listeria growth within a targeted shelf life period,” says Amanda King, technical manager, Kemin Food Technologies, Des Moines, Iowa. “Vinegar is made through a natural fermentation process that produces acetic acid.

“Buffering to a pH similar to the application matrix allows for seamless incorporation into formulas without negative quality impacts, but buffering does not disrupt the functionality of vinegar within the food matrix,” King says. “As a water-soluble ingredient, the dry form is popular and easy to use in a wide variety of applications, from incorporation into spice blends, direct addition to a mixing step or dilution into a brine for injection or marination.”

This type of ingredient can be labeled as simply “vinegar” or “buffered vinegar” on a product label. Buffered vinegar may come in dry or liquid form and have a range of acetic acid concentrations and usage rates.

World Technology Ingredients (WTI) Inc., Jefferson, Ga., offers dry, low-sodium, sodium-free and low-pH vinegar products, along with a liquid blend of lemon juice concentrate and vinegar. The lemon juice enhances product flavor. When used with low- or no-sodium vinegar ingredients, it may be possible to reduce sodium content without impacting taste.

Newly Weds Foods offers a new clean-label ingredient for raw meat and poultry. It can reduce pathogen survival even if undercooked at home or in a restaurant. Based on a proprietary blend of vinegar and plant extracts, the ingredient inhibits pathogen proliferation throughout product processing and distribution. It also substantially reduces potential for cross-contamination and enhances E. coli and Salmonella susceptibility to heat.

“While the vinegar component primarily handles pathogen growth, it is the spice extracts that build in the heat susceptibility and limit cross contamination,” Maehler says.

“This new and revolutionary intervention gives processors, retailers, food service operators and consumers an added level of defense against these food safety concerns,” Maehler says. “It’s an easy-to-use liquid that can be applied directly to ground products and to whole muscle meats by marination.”

Corbion offers a vinegar ingredient that provides the highest concentration of acetate of any vinegar on the market, according to Rourke. The production process is patented in the EU and patent-pending in the US. The company also has a range of ferments made from cane or corn sugar.

“The fermentation produces a variety of organic acids, peptides and other metabolites that are highly effective against pathogens and spoilage organisms,” Rourke says. “We have a new product that combines these ferments with vinegar to deliver an outstanding alternative to high pressure processing. It is labeled simply as ‘cultured sugar and vinegar.’”

DuPont Nutrition & Health, New Century, Kansas, offers a range of cultured products that function as pathogen inhibitors. These are labeled as cultured dextrose or cultured corn sugar.

“During the fermentation process, a variety of antimicrobial products are produced depending on the organism that is used and fermentation conditions,” says Jerry Erdmann, principal scientist, food protection. “Generally, some of the common active ingredients in these products are organic acids or organic acids and peptides.”

DuPont also offers nisin products for pathogen control. One blend is a combination of nisin preparation, rosemary extract, salt and sodium diacetate, and the product is designed for use in cooked sausages and cured meat products. Another blend is cultured dextrose, vinegar and maltodextrin, which can be used in cured and uncured meat and poultry products, raw meat and poultry and ready-to-eat formulated products.

WTI offers patented sodium citrate and diacetate blends. This includes a granular water-soluble blend of buffered sodium citrate and buffered potassium citrate, with the latter assisting with sodium reduction.

“These traditional functional ingredients improve product quality and safety, while increasing yield, stabilizing color and flavor, and reducing purge loss,” says Klaus Kreuzner, director of sales for WTI. “Due to their superior ionic strength – almost twice that of salt – meat processors can increase water-holding capacity while reducing the amount of salt their recipes contain.”

Bioprotection cultures

Another approach to inhibit pathogen growth is to introduce competing microorganisms into the system. Such good cultures have long been used to protect food – from salami to cheese – by reducing the acidity of the food, which in turn inhibits bad bacteria from growing.

Chr. Hansen, Denmark, offers bioprotection cultures for pathogen control in meat and poultry. Bioprotection is a natural way to inhibit spoilage and protect against harmful contamination in food. It refers to the use of safe bacteria, mainly lactic acid bacteria, selected from the natural microflora of food and intended to inhibit unwanted contaminants, prevent food spoilage and provide an opportunity for manufacturers to extend shelf life.

In the meat and poultry industry, bioprotection cultures were first used with traditional starter cultures in fermented sausages. Today, they are used to add an extra layer of safety and microbial quality to other products, including bacon, cooked ham, cooked poultry strips and fresh sausages. The bioprotection cultures do not negatively impact sensory properties of the meat and poultry products. In some applications, protective cultures may actually provide a cleaner taste or keep a fresh taste longer.

These bioprotection cultures are allowed as ingredients in or on processed products labeled as organic or made with organic ingredients, in accordance with the National Organic Program.