Oregon public health officials have issued a warning about cheese imported from Mexico that may be contaminated with Listeria. Oregon’s Health Authority and Department of Agriculture are investigating after an infant in Clackamas County fell ill from the bacteria. The batch of queso fresco was purchased from a Latino grocery store in Woodburn, and officials believe the cheese was brought into the country illegally because it was unlabeled and sold in plastic bags. “If people have this cheese in their refrigerators, they should throw it out or take it back to where they bought it,” said Dr. Paul Cieslak of the Oregon Public Health Division’s Acute & Communicable Disease Prevention section. “Eating it can make people very sick, especially pregnant women, the elderly and those with weakened immune systems.”