Intervening in the Meat Mixing Process to Prevent Pathogens

The average American consumes nearly 200 pounds of meat each year, all of which is processed in some form or fashion. However, at this time, there is no effective food safety intervention in the meat mixing process. The food mixer has inherent food safety risks as various lots, which have various microbial characteristics, are commonly co-mingled in the mixer. Any pathogen in any one lot will be exposed to that entire batch. The mixer is also one of the last points in meat processing in which an antimicrobial hurdle can be applied.

To meet current food safety regulations, temperature control and pathogenic interventions are required. USDA Food Safety and Inspection Service (FSIS) monitoring and regulation of pathogens is increasingly important through proposed rule changes. Therefore, an intervention for the meat mixing process combining best practices in temperature management and a pathogenic hurdle is warranted.

CO2 in the Food Industry

One of the most effective utilizations of carbon dioxide (CO2) in the food processing industry is through bottom injection of liquid CO2 to chill a variety of meat products. At -109 degrees Fahrenheit, LCO2 has the refrigeration capacity to chill a batch of meat during normal mixing cycle times, and at the same time, remove heat gained through grinding, conveying, and mixing without adversely affecting protein extraction. During and after mixing, the food purity grade LCO2 will sublimate out of the mixed meat product leaving no residue. This use of LCO2 can be the most economic means of chilling the product in a mixer in many regions of the country.

Antimicrobial Compounds

Currently, a number of microbial interventions focus on the use of bacteriostatic compounds used in spray, dip, or rinse form to control the spread of pathogens during processing. The development and acceptance of these compounds is driven by their effective control of pathogens with limited to no quality effects on the food product and manageable costs associated with the process.

Table 1.

The approval of the product at its recommended levels must be accomplished through the USDA FSIS Safe and Suitable Ingredients Used in the Production of Meat, Poultry, and Egg Products directive as directed by the FDA. Compounds used in food processing are categorized in one of three ways by the FDA: direct food additives, secondary direct food additives, or processing aids.

According to 21 CFR Parts 172 and 173, direct food additives must be identified on the label and provide technical effects to the final food product, while secondary direct food additives are added during manufacturing but are removed from the final food and have no technical effect on the finished product. Processing aids can be added to the food during processing but are either removed or converted into normal food constituents. Processing aids may also serve as functional additives that leave insignificant, nonfunctional residuals in the finished product. A wide variety of antimicrobial compounds are commercially available including acid, chemical, ovo, lacto, bacto, and phyto antimicrobials, each with unique properties that can be used in food processing facilities at a number of intervention locations.

The Development of CO2+

Since CO2 is a step many processors use in chilling of their product, Air Liquide wanted to incorporate the antimicrobial into the CO2 stream in order to accomplish both chilling of the product and the benefits of pathogen reduction using the antimicrobial compound. This would help to create an additional intervention and have only one step in the process where both could be accomplished in unison.

Air Liquide developed a proprietary process by which an additive or processing aid can be added to the LCO2 stream prior to injection into the meat mixer. The LCO2 is used both as a refrigerant and as a dispersing agent for precisely metered antimicrobial compounds. The LCO2 uniformly chills the product because the mixer uniformly exposes all meat product to the LCO2, and everywhere the LCO2 travels, it carries a precise dose of the antimicrobial. This process, known as CO2+, can also be used to inject a wide range of additives, including preservatives, nutrients, stabilizers, food color, and anti-microbial processing aids.

Technical Evaluation

The combined CO2+ testing and demonstration unit is a 1,000-pound capacity, skid-mounted, commercial meat mixer that has been integrated with a single control panel into the additive metering system, which can deliver precise amounts of additive to the LCO2 supply system.