New bacteria test could improve quality of fruit and vegetable juice.

Increasingly, food and beverage products are being scrutinized for better quality. Scientists at the University of Missouri-Columbia have developed a rapid, reliable and efficient technique to ensure that fruit and vegetable juice products adhere to federal and international quality standards.

Mengshi Lin, assistant professor of food science in the College of Agriculture, Food and Natural Resources, has successfully used a new approach combining a DNA sequencing technique with mid-infrared spectroscopy to rapidly and accurately identify Alicyclobacillus, a common bacterium found in apple, carrot, tomato, orange and pear juices, tropical fruit juices and juice blends. The bacterium won't cause sickness in humans, but affects a product's flavor and can cause spoilage.

Currently, a number of different testing methods are utilized to identify the bacterium, some of which yield false negative results. This has complicated international trade. Japan, along with other developed countries, has a zero tolerance for this bacterium in imported juices.

Identification has been a challenge because spoilage can be difficult to distinguish visibly until test results are confirmed, or after juice products have been opened and tasted by consumers. In addition to agitating taste buds, the latter can affect consumer confidence in a product.

The new technique is significant because it identifies the organism quickly--in a matter of hours, unlike traditional culturing methods, which are time-consuming and require five to seven days to process. Testing time is critical for juice processing companies, which monitor for the bacteria during the processing and final product stage.

The DNA technique in combination with infrared spectroscopy technique won't cause long delays in production. This combination will be the best way to quickly and accurately detect and identify the bacteria, according to the Missouri scientists, who worked with researchers from Washington State University and Hashemite University in Jordan to develop the technique. If processors find the bacteria, they can go back quickly and find the affected products.

Further information. Mengshi Lin, Department of Food Systems and Bioengineering, University of Missouri-Columbia, 256 Stringer Wing, Columbia, MO 65211; phone: 573-884-6718; fax: 573-884-7964; email: linme@missouri.edu.