To the home-based cook, a marinade typically means a mixture of vinegar or wine and oil, infused with a generous smattering of spices and seasonings. When meats are soaked in such a marinade before cooking, they reap flavor and tenderness benefits.

On the commercial side, marinades, or brines, also add flavor and tenderness to meat and poultry products. In addition, they often incorporate additional ingredients that work specifically to boost safety and extend shelf life. However, proper preparation and application of the marinade — and operation and care of the application equipment — are crucial.

The number-one ingredient in almost all commercial marinades and brines is water.

“Water is a functional ingredient because it is what we [use to] dissolve or suspend the ingredients in a marinade,” says Rick Hull, marination technologist for Athens, GA-based World Technology Ingredients Inc. (WTI). Yet processors often overlook or underestimate the roles water quality and source variability play in marinade performance, he says.

For example, research conducted by Romeo Toledo, Ph.D., at the University of Georgia has shown that marinade retention and process yield decrease as water hardness increases. Water with as little as 50 parts per million (ppm) calcium carbonate (CaCO3) will reduce marinade retention. In addition, pH variations and contaminants such as nitrates contribute to product defects such as pinking.

“We recommend that water for marination be purified via reverse osmosis to remove all contaminants and maximize functionality,” notes Hull.

Although the most effective marinades begin with a good water source, the whole idea of ingredient-based shelf-life extension of meat and poultry started with salt via surface rubs and brines.

“Initially, salt was intended as a preservative to help extend shelf life,” notes Greg McMillion, a vice president with West Chicago, IL-based Mepsco Inc. The ingredient since has been shown to boost flavor, juiciness, and tenderness, he adds.

Salt also provides ionic strength to marinades. “Since water is bound to muscle proteins via ionic bonds,” says Hull, “ingredients which contribute ionic strength help the marinade bind to the muscle protein system.”

Phosphates, too, play a critical role, says McMillion. “The high pH of phosphate makes the muscle proteins more soluble, improving the water-holding capacity of the product. By binding the water to the muscle, it helps reduce purge in the finished product and helps extend shelf life,” he says.

In addition to water, salt, phosphates, and flavor and aroma boosters, commercial brines generally include sugars and a curing compound such as sodium nitrate, says Marcy Epstein, M.P.H., C.N.S., C.D.-N, director of research and development for Long Island City, NY-based First Spice Mixing Co. Inc. “Sugar and/or dextrose dissolve in water and limit free water needed to support microbes,” she says. “Specific blends of sodium phosphates dissolve in water for pumping and also have the advantage of binding water in the interstitial compartment of muscle, helping to retain water during the cooking process. The curing compound is an antibacterial [and] fixes the color of red meat and stabilizes the oxidation of fat, helping to increase shelf life.”

First Spice offers a combination of USDA-accepted GRAS (generally recognized as safe) organic acids that decrease bacteria, including Listeria, in meat and poultry products, says Epstein. Its Meatol and Meatol-P (for poultry) products help to reduce pH to create conditions adverse to microbe growth, while minimizing the flavor carryover and point-of-entry meat denaturization associated with many other acids.

Antioxidants such as butylated hydroxytoluene (BHT) and sodium tripolyphosphate and natural ingredients such as rosemary extract help to mitigate the dreaded warmed-over flavor (WOF) in pre-cooked or partially cooked meats.

“The first indication of [WOF-related] quality losses is the decline in the characteristic meaty notes, followed by a stale or cardboard flavor, and then rancid off-flavors,” says Jeff Sporrer, marketing manager for the Food Ingredients Division of Kemin Americas Inc., Des Moines, IA. His company offers the Fortium™ brand line of natural rosemary extracts, which can be incorporated into marinades to help maintain freshness.

“Maximum shelf life for meats will be obtained by including salt, phosphates, antimicrobials, and rosemary extract into a marinade,” says Kristen Robbins, R&D manager for the Food Ingredients Division of Kemin Americas. “Since salt and phosphate increase marinade uptake and retention, the rosemary extract will penetrate the meat matrix more thoroughly.”

Rosemary extract can be listed on product labels as a natural flavoring or a spice extract, notes Sporrer, a fact that should appeal to consumers seeking natural-ingredient options to shelf-life extension.

Salts of organic acids such as sodium or potassium lactates, sodium diacetates, sodium acetate, and sodium or potassium citrates are among the most common antimicrobials added to brines to extend shelf life, notes René Monderen, senior market development specialist for Lincolnshire, IL-based Purac America Inc. The company is the largest producer of natural lactate and its derivatives, sodium lactate and potassium lactate, he notes.

“Besides the lactate products, we also produce combinations of lactate and diacetate,” says Monderen. “This combination is in great demand for ready-to-eat producers because of the synergistic effect between lactate and diacetate. One of the main reasons for using [it] is to control Listeria growth.” The lactate or diacetate solution should be the final ingredient mixed into the brine, notes Monderen, to prevent the other ingredients from coming out of solution.

If they define marinade, process, and finished product performance criteria upfront, processors will be able to select the best system for the product and process, says Hull. “While lactate and lactate-diacetate blends are available as solutions, buffered citrate and citrate-diacetate blends are available in the dry form,” he says, “where they can be incorporated into cures and seasoning mixes or added directly to the marinade.”

Proper preparation is vital to marinade function and product safety.

“Improper mixing and chilling procedures can limit the benefits of some ingredients if not followed in the proper sequence,” says McMillion. “Ingredients that are not fully dissolved and hydrated limit the effectiveness of the marination in the product.”

The brine solution must be chilled not only when it is being made, but also throughout the entire process, stresses Rich Hardin, technical sales specialist for Canton, MA-based Reiser. Because some processing equipment generates significant amounts of heat, tumblers and other mixing equipment should have refrigerated jackets to maintain or reduce the temperature of the product during processing, he adds.

The marinade should be kept at a consistent chilled temperature, normally between 28° F and 34°F, says Dale Hunt, head of the application specialist team for Kingston, NY-based Wolf-Tec. The company offers the jacketed and insulated Polar Dissolver Mixer/Chiller, which features a programmable temperature control to keep the temperature consistent, he adds.

High-shear mixers fully hydrate the functional ingredients, says McMillion. “Temperature can be precisely controlled by re-chilling the return brine from the injector holding tank using a double-tube heat exchanger.”

Refrigerated mixing and storage components, including high-shear mixers for certain types of brines, are becoming more important, notes Jim Ryan, vice president of sales for Nu-Meat Technology Inc., South Plainfield, NJ. “That’s really key — to get the brine thoroughly mixed, in the proper rotation,” he says.

Ingredients not only must be added in the proper order, but also must be given time to dissolve before the next constituent is added to the mix, says Hardin. Although venturi-type addition hoppers and high-shear mixers can speed up the process, the operator still must follow proper mixing procedures. To prevent needle blockage and cleaning problems in injection systems, operators must take special care with settleable solids such as food starch.

Phosphates must be mixed for a minimum of five or six minutes before the other ingredients are added, notes Ryan. “If you add the salt before the phosphate is totally in solution, the salt makes the phosphate precipitate, drop out of solution,” he says. “Then it doesn’t become functional — it ends up on the bottom of your tank and will affect your yield, retention, etc.,” he says.

Standard operating procedures for marinade preparation also are important, notes Hunt. “Many times, the marinade is made totally differently between the day shift and the night shift.”

Processors might use a spray, a dip tank, or another method to apply marinades topically to products such as steaks or precut chops, says Hardin. Topical application is appropriate when the processor seeks the benefits of an antioxidant, for example, with minimal absorption into the product.

However, the two most popular methods for marinade application are vacuum tumbling and injection, says Robbins, both of which allow penetration into the meat tissues. Each offers its unique advantages and disadvantages.

“Injection marinades offer better penetration, but the trade-off is the disruption of the muscle fibers and a tendency to create a product with a soft, mushy mouthfeel,” says Robbins. “Vacuum tumbling will offer homogenous distribution of brines in thinner cuts of meat, but in large roasts, the marinade will not fully penetrate. However, there is less penetration of the muscle fibers, so the texture is more firm.”

Tumblers, mixers, and mixer/massagers accelerate the soaking – or marinade absorption – process through mechanical action, explains Hardin. However, these batch-type systems require more time than injection-type systems. In addition, he says, tumbling can change the physical appearance of the product and distribute a higher concentration of ingredients at a thick product’s surface than at its center.

Injection generally is recognized as the most time-efficient method.

“Recent innovations in injection technology have improved overall product quality [and] appearance and helped maximize yield,” says McMillion. Still, injection accuracy and uniformity are critical to maximizing product safety and shelf life, he says. Processors can minimize loss and purge by ensuring precise control of the needle manifold, by injecting cold brine at a constant low pressure with clean needles, and by maintaining the correct needle pattern and needle density.

No matter how potent the marinade, product shelf life will be compromised if sanitation and maintenance procedures are sub-standard. For example, the injection process could introduce bacteria into the product.

Equipment design can either help or hinder sanitation procedures.

“It is critical that the equipment used for processing be designed to be cleanable and to operate without allowing product debris to build up during the processing day,” says Hardin. “Crevices that trap product can start to feed back bacteria within a few hours. Tumblers with areas that are difficult to clean and inspect can cause serious contamination problems. Injectors must either be designed so a clean-in-place (CIP) process can effectively clean them, or they must be disassembled for cleaning to prevent buildup in manifolds or other areas where debris can settle.”

Nu-Meat offers a “very easily accessible” injector, notes Ryan. “You can slide the whole assembly out left or right, completely removing it from the machine very easily.”

The wide-open, exposed design lends itself very easily to sanitation, Ryan says. Operators can totally disassemble the unit, including the needles, in approximately 20 minutes.

A soap and chemical solution beginning in the mixing tank and run all the way through the system can clean the tank, the tube-and-shell heat exchanger, and the injector, says Ryan. Nu-Meat also instructs its customers to soak their needles overnight in a caustic solution and blow them out with air in the morning.

Wolf-Tec’s latest injection equipment can be broken down completely for cleaning, says Hunt, a process that ensures the cleaning solution hits every nook and cranny within the system. The company’s IMAX injectors offer a “brine path that is totally visible,” he adds, one that breaks down quickly and easily for daily cleaning.

Ultraviolet disinfection (UV) provides yet another means of sanitation and product safety, disinfecting excess marinade before it is recirculated into the injector.

“Through the course of a normal production shift, bacterial counts in brines and marinades can typically achieve levels of 105 and often peak or spike to levels as high as 108,” says Chris Coleman, product manager for Little Rock, AR-based Safe Foods Inc. “During the injection process, bacteria from the meat surface may be rinsed from the meat by the excess brine/marinade into the marinade reservoir. The marinade then is injected internally into subsequent pieces of meat.”

To deal with this problem, Safe Foods created the FreshLight® 200 system, which the company says is the only UV disinfection product designed specifically for the continuous disinfection of opaque fluids such as marinades. Maple Leaf Foods and Swift & Company are among the food processors that have given the product their seal of approval, notes Coleman.

The core of the system is the patented Liquid Flow Module, which increases turbidity of the passing marinade to expose more of its surface to UV light. This results in better bacteria control, says Coleman. Each system first is tested using customer product in Safe Foods’ lab to adjust for unique application parameters, he adds.

To lessen microbial concerns — and attain optimum processing results — operators must closely follow manufacturer-recommended guidance related to equipment. Many companies offer equipment-specific training.

Essentially, the effectiveness of the marinade applied to a meat or poultry product will be determined by the cumulative success — or failure — of each one of the vital manufacturing steps.

“Not every microbe is pathogenic, and some microbes compete out for unhealthy ones, says First Spice’s Epstein. “However, in today’s environment, we are trying to limit both in hopes of extending the shelf life. There is no substitute for good manufacturing practices.”

As Reiser’s Hardin puts it: “Many companies are working on ‘fairy dust’ or ‘magic bullet’ products, but we can never forget about the basics.”
Ingredient and equipment suppliers in this article include:
• First Spice Mixing Co. Inc., phone (718) 361-2556, or visit www.firstspice.com
• Kemin Americas Inc., phone (515) 559-5100, or visit www.kemin.com
• Mepsco Inc., phone (800) 323-8535, or visit www.mepsco.com
• Nu-Meat Technology Inc., phone (908) 754-3400, or visit www.nu-meat.com
• Purac America Inc., phone (847) 634-6330, or visit www.purac.com
• Reiser, (781) 821-1290, or visit www.reiser.com
• Safe Foods Inc., phone (501) 758-8500, or visit www.safefoods.net
• Wolf-Tec Inc., phone (845) 340-9727, or visit www.wolf-tec.com
• World Technology Ingredients, phone (706) 355-3007, or e-mail at WTI_inc@bellsouth.netAll the bells and whistles

Today’s equipment suppliers offer marinade application solutions that address cleaning concerns, automatically adjust temperature, and much more. A small sampling of the latest innovations includes:

The new ULTRA Series of injectors from Mepsco, which feature maximum cleanability and easy sanitation, a high-polished exterior stainless steel surface, large access doors, and a hinged hood with a convenient tilt-back air head for easy needle removal. The units also offer the first self-cleaning filter system with a waste auger. An early warning system for protection against operator error has a low-level brine tank sensor and a temperature display with flashing warning lights that go off when the temperature increases beyond a preset point. “Smart Choices” are customizable features that allow processors to choose between features such as a hydraulic or mechanical drive.

Nu-Meat Technologies’ injectors use a very high-pressure atomized spray to inject at higher pressures than other models, but through very small conical holes. The very fine atomized mist that is created covers a wide area, resulting in excellent retention and better distribution within the meat or poultry product. The company’s Metalquimia Auvistick series is designed for marination applications ranging from 3- to 30-percent injection, while its Metalquimia Movistick series is for higher injection applications, from 10 to 100 percent. Nu-Meat also offers a UV brine-disinfection system that combines filtering with water treatment, water deionization, and multilevel UV for bacterial reduction.

Reiser offers the FOMAC New Generation line of injectors, which facilitates complete cleaning of the brine path using the CIP program. The design requires minimal disassembly and lends itself to quick, easy cleaning of the product-transport system and other surface areas. Its modern filtration system ensures accurate injection throughout the production shift. Reiser also supplies refrigerated and non-refrigerated brine mixing and storage systems, as well as a complete line of AMFEC-built refrigerated and non-refrigerated mixing, massaging, and tumbling equipment for topical applications.

Wolf-Tec’s IMAX series of injectors offers a very high injection consistency, needle removal without tools, the greatest level of hygiene, and minimal maintenance. Each unit allows complete, easy access to the brine path for thorough sanitation. The company’s Polar Dissolver Mixer/Chiller provides touch-panel controls to monitor solution temperature and mixing time or to upgrade the control panel to include recipe programming. A stainless steel transfer pump moves the finished solution to the required destination, while a modular piping design allows the seamless addition of extra units. Wolf-Tec’s latest product, the POLARVISION technology, allows remote monitoring and control of all the company’s product lines. It records hundreds of control points for process validation and provides a programmable interface for recipe control and alert notification.