Several people from a picnic came down with a gastrointestinal disturbance, and public health officials suspected a case of food poisoning. The food, especially hot dogs, were cultured and after 24 hours of growth on sheep blood agar (SBA), there was a small, round, smooth, translucent colony surrounded by a narrow zone of Beta-hemolysis. A Gram stain showed gram-positive coccobacilli. Motility medium was inoculated and an umbrella pattern of motility was observed at room temperature. What organism was isolated as the cause of the illness?