(Reuters) – A semi-trailer hauling thousands of pounds of hamburger crashed and caught fire early Thursday on a western Michigan highway causing an extensive backup amid the smell of burning meat, police said. The refrigerator truck carrying meat and other food products was traveling east on Interstate 94 near Jackson, Michigan, when it crossed the median, turned onto its side and burst into flames in the westbound lanes, police said. The driver, a 69-year-old man from Pennsylvania, was treated for minor back injuries at a local hospital while a dog riding in the truck was unharmed, said John Johnston, deputy director of the Blackman/Leoni Department of Public Safety.