Thermal inactivation of hog cholera virus in ham.

Experiments were conducted to determine the temperatures required to inactivate hog cholera virus (HCV) in fresh ham after 1 minute and in cured and processed (canned) ham after 90 minutes. A momentary or "flash" temperature of 71 C for 1 minute caused inactivation of the virus in 15 of 15 cubes (2 cm3) of ham. Hog cholera virus was destroyed in 21 of 21 canned hams (weighing 0.91 kg each) when an internal temperature of 65 C was sustained for 90 minutes. Pigs were found to be more sensitive than tissue culture cells for detecting viable HCV in heat-processed fresh hams. Virus was isolated by tissue culture technique only from those hams exposed to temperatures below 61 C. The relative concentration of HCV in unheated cured hams of experimentally infected pigs varied over a wide range; these pigs were inoculated with the virulent Ames strain and were killed on postinfection day 6 or 7.