A Bacteriological Study of Stored, Sulphite Treated Peeled Potatoes

SUMMARY Peeled, sulphite treated potatoes were stored at 23° for 3 days or at 6° for 7 days in packs sealed with perforated or unperforated polythene or with Saran film. After storage, gas samples were withdrawn from the packs for analysis and viable counts made of micro organisms associated with the potatoes. There was a marked increase in the CO 2 concentration and a corresponding decrease in O 2 concentration in the unperforated packs; samples from these packs tended to have a lower bacterial count than samples from perforated packs. 180 bacterial isolates representing the spoilage flora were examined. At 23° the major groups of isolates were Gram negative bacteria attacking glucose fermentatively (Enterobacteriaceae) or oxidatively (fluorescent pseudomonads); isolates from storage at 6° were all pseudomonads most of which were fluorescent. Twentyeight % of the pseudomonads, but none of the fermentative isolates, were pectolytic.