New applications possible for chemical spray.

Meat processors may have another tool at their disposal for reducing levels of pathogenic bacteria. Tests at Kansas State University show that spraying a chemical on frankfurters and pork carcasses reduces pathogenic bacteria more effectively than washing the products in water.

Acidified sodium chlorite reduced L. monocytogenes when researchers applied it to frankfurters in the processing plant. Reductions increased as exposure time to the chemical increased. Also, acidified sodium chlorite reduced the levels of E. coli and Salmonella when applied to pork carcasses during processing after slaughter.

Hot dogs usually have loosely attached organisms called plactonic cells. Regular washing with pressurized water and any similar treatments will remove some of the microbial cells from the surface. But when researchers use acidified sodium chlorite, they experienced better reductions compared to washing with water or dipping the product in water.

The chemical treatment is effective on ready-to-eat meat products because the surface is cooked. The treatment is also effective on animal carcasses because the presence of organic material does not inactivate the chemical.

Before the process heads for industrial use, the research team suggests undertaking studies to evaluate the chemical treatment's effect on sensory attributes, such as color and flavor. There have been slight changes apparent. For pork carcasses, organic acid rinses, such as lactic acid or acetic acid, are the predominant treatment in the processing plants. Acidified sodium chlorite is used in poultry processing. In all cases, acidified sodium chlorite may become the most popular because of its superior performance.

The advantage: you can incorporate the spray process with minimal changes in capital investment in the present organic acid rinse system, we're told. The next step for researchers will be to conduct in-plant validations of the procedures for pork carcasses that they have tested at the university, similar to the in-plant validations already underway in beef carcass processing plants.

Future research may cover ways to extend these antimicrobial treatments to ground beef trim. Investigators are looking at a research project in which they can evaluate the effects of acidified sodium chlorite, hot water and organic acid rinses for beef trim that is supposed to go to ground beef manufacturers. USDA regulations do not allow those treatments now because of the added water. When you do these washes you inevitably add some moisture to the product.

Further information. Harshavardhan Thippareddi, Kansas State University, Department of Animal Sciences and Industry, 210 Call Hall, Manhattan, KS 66506; phone: [phone]; fax: [phone]; email: [e-mail].