Sent_en: 2zh Joan Rose, a microbiologist and food safety expert at Michigan State University, commented that it is not surprising that cattle manure was the source of the infection.
Sent_yy: 密歇根州立大学的微生物学家和食品安全专家琼安·罗斯评论说，这样一来，牛粪是感染源就不奇怪了。