Antimicrobial Belt Treatment Reduces and Controls Microorganisms

Application of a sanitizing solution registered with the Environmental Protection Agency (EPA) to conveying equipment during production can help reduce the incidence of undesirable microorganism contamination on critical meat, poultry, fruit, and vegetable conveyor surfaces. Such sanitizers, approved for incidental food contact, can provide critical intervention. Benefits of a continuous antimicrobial belt treatment include protecting your brand and investment in product, reducing and controlling microorganisms on conveyor belts, and possibly enhancing product shelf life.

A successful continuous or intermittent belt treatment program requires the use of an EPA-registered sanitizer. The product use directions will indicate organism efficacy, sanitizer concentration, and sanitizer exposure time. In addition, the product injection system, spray bars, and valves must be compatible with sanitizer chemistry.

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In any meat processing plant, fat and meat residue accumulate in conveyor transfer belts throughout the production day. This creates an environment in which microorganisms can increase as a direct result of cross-contamination between products and belt, resulting in as much as a six-log increase from the beginning to the end of the production day.

Continuous treatment of the belt with an EPA-registered antimicrobial product helps reduce and control those microorganisms. The level of success achieved depends on the choice of sanitizer, adequate feed and control equipment, and proper application. The product conveying system must be cleaned and sanitized prior to start-up. An EPA-registered sanitizer approved for incidental food contact, with label directions for use as a continuous belt treatment, must be used for this application. Additional consideration should be given to the desired outcome in terms of sanitizer formulation and efficacy.

A recent study conducted by Zhinong Yan et al at Michigan State University and presented at the 2008 meeting of the International Association for Food Protection assessed the efficacy of two liquid sanitizer products at label-use concentration in killing Listeria monocytogenes inoculated onto interlocking and continuous conveyor belts. A peroxyacid-based product and a sodium hypochlorite-based product were evaluated; water was the control.

A short-track conveyor was equipped with both interlocking and continuous belts that looped through a vessel of 10% turkey slurry contaminated with L. monocytogenes. The belts were conducted through the meat slurry five times and allowed to dry for 15 minutes and were then sprayed with sanitizers for up to 60 minutes. Microbial analysis of belt surfaces was conducted at frequent intervals for the duration of the treatment. The study was repeated three times.

Study Results

The peroxyacid-based sanitizer resulted in significantly (P�0.05) greater microbial reductions on interlocking belts than the sodium hypochlorite-based sanitizer and the water control. After 20 minutes of treatment with the peroxyacid-based sanitizer, populations of the pathogen were reduced by almost five logs; the sodium hypochlorite-based sanitizer reduced L. monocytogenes by less than four logs after 60 minutes.

On the continuous belt, the peroxyacid-based sanitizer was again significantly more effective (P�0.05) than a sodium hypochlorite-based product. A five-log reduction was achieved after a five-minute application of the peroxyacid-based sanitizer, whereas 20 minutes was required to achieve the same level of efficacy with the sodium hypochlorite-based product.

Under the conditions of the study, the peroxyacid-based sanitizer was more effective than sodium hypochlorite in killing L. monocytogenes on contaminated conveyor belts.

System Considerations

There are several things to consider when installing and using chemical injection systems. First, consider the location of personnel and equipment. The use of spray bars will always involve over spray, misting, dripping, or chemical odors. Avoid locating the spray bars on overhead conveyors when there are personnel working underneath or near equipment that will be adversely affected by water or chemical exposure. If the location demands it, install drip pans to protect personnel or equipment.