The nuclear-polyhedrosis virus ofTrichoplusia ni(Hübner) (T. niNPV) and the granulosis virus ofPieris rapae(L.) (P. rapaeGV) added to shredded cabbage before sauerkraut fermentation were at least 75% inactivated during fermentation.T. niNPV andP. rapaeGV added after fermentation were inactivated by pasteurization of the fermented sauerkraut.Bacillus thuringiensiswas not inactivated during fermentation and was only partially inactivated by pasteurization of fermented sauerkraut.The small quantities of the viruses found in nontreated shredded cabbage were inactivated during sauerkraut fermentation.