The hope is that enteric viruses will lose infectivity between when they are shed and when someone else ingests them (Rzezutka and Cook 2004) . In addition to the NASA studies described above, we considered foods with a rich bacterial flora that might cause biodegradation of contaminating virus. Lynt had reported that spoilage of several foods held at room temperature had little effect on the persistence of inoculated enteroviruses (Lynt 1966) . Because CA9 had been found particularly vulnerable to proteases (Herrmann and Cliver 1973a) , it was chosen as the model contaminant in a study of sausage fermentation and of microbial spoilage of ground beef (Herrmann and Cliver 1973b) . Although proteolysis (putrefaction) was very evident in the ground beef, less than one log of inactivation was recorded by 8 days at either 4 or 23°C; however, substantial reductions were seen at 14 days. Earlier, Kalitina had reported that group B coxsackieviruses persisted equally well in ground beef that had or had not been autoclaved (Kalitina 1966) . CA9 was 84% inactivated during 24 h of Lactibacillus fermentation at 30°C in making Thuringer sausage (pH reduced from 6.0 to 4.8); subsequent heating of the sausage for 6 h at 49°C left just 0.1% of the original inoculum infectious (Herrmann and Cliver 1973b) . Kalitina had also reported that cottage cheese fermentation did not affect enterovirus persistence (Kalitina 1969) . We studied the various stages involved in making cheddar cheese and found that pasteurization of the milk caused a million-fold inactivation of PO1; however that if the virus was added with the starter culture, then there was about 98% inactivation during cheesemaking and little additional virus loss during 7 months of storage of the product at 4°C (Cliver 1973b) . Influenza A and vesicular stomatitis viruses, on the other hand, were undetectable in the pressed curd at the end of the cheesemaking process ([5-log inactivation) .