Over 300 samples of different foods packed in hermetically sealed containers were examined for wholesomeness, subsequent to a pre-incubation suitably adapted to their mode of processing and intrinsic antimicrobial parameters : a, , pH and concentration of inhibitory substances. Those in Group 1 were incubated for 5 days at 17fl"C, those in Group 2 for 10 days at this temperature and Group 3 for 30 days at 30°C.Among ninety-one samples examined in Group 1, 14% did not meet generally accepted criteria for microbiological wholesomeness and 35 yo showed minor deficiencies. This indicates that the pre-incubation period of 5 days at 17°C applied to these commodities was excessive. More desirably a period of 3 days should be employed for such products. On the other hand, none of the seventy-four samples from Group 2 showed serious bacteriological deficiencies after incubation for 10 days at c. 17°C and only in 9.5% of the samples total counts exceeded the specified levels. Among 145 shelf-stable canned 'appertized' samples only 1.4% showed minor deficiencies after incubation for 4 weeks at 30"C, i.e. counts slightly over 102/g, a level already previously found generally not to be exceeded in correctly appertized foods, subsequent to such an incubation.