‘Tis the season for charcuterie boards featuring ready-to-eat meats and cheeses. These grazing boards are a giant petri dish. The longer these perishable items stay uncovered at ambient temperature and the more hands that touch the serving utensils, the greater the risk of microbial contamination.

“Most charcuterie meats and cheese are tastiest when served at room temperature,” said Kris Boulton, extension agent, University of Arkansas Division of Agriculture, Benton, Ark. “Perishable items shouldn’t sit out for more than two hours.”

Most hosts are not watching the clock. That’s why meat processors should assist with reducing the risk of foodborne illness through the addition of food safety ingredients. Those prioritizing clean label will often include various plant extracts and vinegar-based ingredients.

The inclusion of such ingredients may have helped prevent a super-spreader outbreak that started in early November. A Listeria monocytogenes occurrence across six states was linked to sliced meats and cheeses purchased at retail deli counters. These products may very well have been intended for charcuterie boards. More than 13 people were hospitalized and at least one death has been attributed to the foodborne illness, according to the US Centers for Disease Control and Prevention, Atlanta.

A statement on the CDC website explains that it is challenging to identify a single item as the culprit.

“This is because Listeria spreads easily between food and the deli environment and can persist for a long time in deli display cases and on equipment,” the agency said. “A contaminated food likely introduced the outbreak strain of Listeria into delis in multiple states. Investigators are working to identify any specific products or delis that may be contaminated with the outbreak strain.”

The CDC advised high-risk people to avoid eating meat or cheese from any deli counter unless it is heated to 165° F to kill the pathogen. The agency also advised food retailers and deli operators to be vigilant and follow USDA-FSIS food safety best practices.

The power of vinegar

If these meats had included vinegar in the recipe, they may have been protected from the omnipresent Listeria. Straight vinegar, as well as buffered vinegar ingredients, are recognized for their food safety benefits and appreciated for their all-natural reputation.

Consumers know vinegar. It’s long been in most kitchen pantries. Vinegar is the fate of drinking or grain alcohol exposed to oxygen and acetic acid bacteria, those from the genus acetobacter. These bacteria metabolize alcohol into water and acetic acid, producing the very stable, multi-functional liquid known as vinegar.

Although acetic acid is the primary constituent of vinegar after water, acetic acid is not vinegar. Acetic acid, as well as other food-grade acids, namely lactic acid and propionic acid, are the most common organic acids used to inhibit pathogenic and spoilage microbial growth. They are often used in a buffered or neutralized format (with a conjugate base). Their mode of action is the same, but their effectiveness varies by the organic acid, specifically the amount of undissociated or non-ionized acid. It is the undissociated acid that penetrates microbial cell walls. Once inside the microorganism, where the pH is near or above neutral, the acid dissociates, lowering the pH. The pathogens and spoilage microorganisms encountered in the meat and poultry processing and distribution environment are pH-sensitive; thus, this change in pH impairs or stops growth. Further, the anionic parts of the organic acid, which are the negatively charged ions, remaining in the microorganism will accumulate, disrupting metabolic functions. This leads to an increase in osmotic pressure that eventually destroys the microorganism.

It is the amount of undissociated acid that determines the organic acid salt’s effectiveness as an antimicrobial. Dissociation is dependent on pH and quantified by pKa value. The pKa of an acid is the pH where 50% of the acid is undissociated. Propionic acid has a pKa of 4.87 and acetic acid’s is 4.75. Lactic acid is much lower at 3.83.

When pH is higher than pKa, the amount of undissociated acid decreases and the acid is less effective at destroying undesirable microorganisms.

In addition to acetic acid, vinegar contains vitamins and other compounds inherent to the substrate material. Some of these are responsible for imparting color and unique flavors to vinegar. Some vinegars further develop color and flavor from being fermented or aged in wood barrels. There are many varieties of commercial vinegar, which are often used in meat and poultry marinades. The type of vinegar produced, and its corresponding color and flavor, depends on the substrate being fermented. Depending on the variety, vinegar can contribute buttery, malty, savory, sweet and even woody flavors.

Vinegar ingredients have long been appreciated by meat and poultry processors for their contribution to tenderizing, preserving, enhancing flavor and even influencing color. Suppliers offer vinegar ingredients in dry and liquid extract formats, with or without other functional or flavorful ingredients.

The US Food and Drug Administration addresses vinegar in its Compliance Policy Guides. The agency said that an ingredient can be labeled vinegar when the product contains in excess of 4 grams of acetic acid per 100 milliliters. When vinegar is diluted with water, the label must bear a statement indicating such, as well as specify the acetic acid strength as a percentage, with that percentage always being greater than 4%.

Two of the more common fruits used in vinegar production are apples and grapes, which respectively yield apple cider vinegar and (red or white) wine vinegar. There’s also various spirit — champagne, sherry, etc. — vinegars, as well as malt (made from malted barley) vinegar.

Distilled white vinegar is the most common and most economic vinegar. It is industrially produced using grain alcohol as the base material and is almost pure acetic acid without any color or flavor. Balsamic vinegar, on the other hand, is likely the most expensive and complex vinegar, with color and flavor varying by grape combination and aging process.

Although balsamic is often classified as a wine vinegar, it is not, since it is not made from wine. It is produced using a single-step process with a special yeast and bacterial culture mixture fermenting grape pressings, also known as must. This is a juice that is not first fermented into wine. Rather, the concentrated grape juice is converted into alcohol and acid at the same time. Balsamic vinegars further undergo a lengthy aging process for color and flavor development.

If food safety is the only function a processor is looking for in vinegar, then a buffered vinegar ingredient may be the best solution. Available in liquid and dry formats, buffered vinegar does not negatively affect meat quality, including parameters such as water-holding capacity, protein denaturation, color or flavor. The dry version is almost four times as strong as the liquid, which means usage levels are lower with the dry product. Buffered vinegar may be added via a brine, marinade, spice blend or direct application to meat. Ingredient statement declaration is as “vinegar” or “vinegar powder.”

Buffered vinegar systems may contain either sodium or potassium cations. Manufacturers trying to manage sodium content levels will often opt for the potassium version. They are equally effective at inhibiting growth of pathogens and spoilage bacteria; however, depending on application, there’s always that chance the slight bitterness of potassium may be detectable.

Plant extracts’ role

Rosemary and green tea extracts are often combined with buffered vinegar for a multi-prong approach to extending shelf life by addressing color retention and food safety with one ingredient. Often when combined, the ingredients work synergistically, allowing for a lower usage rate for the same effect.

Both rosemary and green tea extracts contain phenolic compounds that function as antioxidants, preventing oxidative breakdown of meat pigments by being oxidized themselves. The main difference between the two plant extracts is that green tea extract has a lower negative flavor contribution to the final product. Thus, using a lower level of rosemary extract in combination with green tea extract allows the manufacturer to increase the natural plant extract usage rate, often resulting in an extract blend that works better in the meat product than using rosemary alone.

Acerola cherry extract is also proving to be a highly effective ingredient in meat and poultry. Extracted from the namesake wild plant grown in tropical and subtropical regions, acerola extract contributes the antioxidant vitamin C. The ingredient has been shown to delay both lipid and myoglobin oxidation, thereby delaying the onset of color loss and maintaining the desirable color and quality of meat products. When used in combination with rosemary and green tea extracts, acerola is more effective at delaying early discoloration than either extract alone.

Some natural plant extracts, most notably those with high concentrations of polyphenols/flavonoids and antioxidants, have also been shown to be effective against specific pathogens. Suppliers customize blends for specific applications for both fresh and ready-to-eat meats in order to preserve color and flavor while providing protection against pathogens.

P-Coumaric acid is a naturally occurring polyphenol found in wine, vinegar, honey, tomatoes, basil, garlic, several edible plants, many fruits and cereal grains such as oats. P-Coumaric is a potent antioxidant that can inhibit lipid peroxidation and radical scavenging, comparable to the chemical preservatives butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), as well as alpha-tocopherol and ascorbic acid. It is also an effective antimicrobial against Escherichia coliform and Staphylococcus aureus.

Hydroxytyrosol is a phenol found in olives. Applications include all types of sausages. Not only does hydroxytyrosol inhibit fat oxidation, published research shows promise in its ability to slow microbial growth and prevent discoloration in meats.