The two principal legal pasteurization methods for milk in the USA are the low-temperature, long-time method (LTLT: 63°C, 30 min) and the more common high-temperature, short-time method (HTST: 72°C, 15 s). We found that HAV was somewhat more susceptible to LTLT pasteurization than to HTST pasteurization in both homogenized, pasteurized whole milk and in raw whole milk. Inactivation was 94% by LTLT and 27% by HTST in raw milk (Mariam and Cliver 2000b) . This study was inspired by an earlier Michigan outbreak of HA in a religious group that did not use electricity or machinery. They milked their cows by hand (with highly inadequate hand-washing facilities) and sold it to a neighboring cheese plant; these data indicated that the cheese produced after the milk was pasteurized would not have been safe, in contrast to our earlier result with poliovirus (Cliver 1973b) .