Retarding potato spoilage and cleaning food-processing water.

USDA-ARS scientists are seeking to improve the safety of a variety of processed foods. They're doing this by developing new technologies for applying disinfectants to such bulk food items as potatoes and poultry and by creating technologies that remove microbes from food processing systems.

One aspect of this effort involves disinfecting stored potatoes. There is concern over the appearance of new strains of fungus, specifically Phytophthora infestans, that cause the late blight disease and which triggered the Irish potato famine of the 1840s. These strains have been found throughout all major potato-producing areas of the United States.

The new strain resists the fungicide that controls the original type of late blight and can destroy a crop within weeks. Even if the late blight infection did not destroy the growing plants, the infection of tubers threatens the processing industry that relies heavily on stored potatoes for a year-round supply of raw materials.

Researchers have developed a process to control potato spoilage by introducing chlorine dioxide gas to the air circulation system of the storage facility. Chlorine dioxide can control the spoilage of potatoes inoculated with heavy doses of microorganisms and does not leave measurable residuals. The process is being reviewed by the Idaho Agricultural Department as a way to solve that state's urgent need in this area.

In other aspects of the research program, scientists are applying specialized filtration technologies to remove microbes from food processing water. The goal here is to extend the use of the water, reduce the total microbial count and reduce the volume of water that is eventually disposed. This approach has been examined in a food processing plant at full production scale.

This research will impact the consumer by improving the safety of bulk-processed foods, and it will help the processing industry by creating more cost-effective processing technology and improved product reliability. As the research contributes to minimizing disinfectant use it will impact international trade decisions related to the use of chlorine disinfectants. This research will also impact our understanding of the complex chemistries of disinfection that involve the use of chlorine and chlorine dioxide and will help develop rational control strategies for food disinfection.

Further information. Lee Tsai, USDA-ARS Western Regional Research Center, 800 Buchanan St., Albany, CA 94710; phone: [phone]; fax: [phone]; email: [e-mail].