STREPTOCOCCUS FAECALIS AND STREPTOCOCCUS FAECIUM IN FROZEN VEGETABLES. INCIDENCE AND SURVIVAL AFTER TREATMENTS COMMONLY USED AT THE VEGETABLE FREEZING PLANTS

Abstract

S. faecium predominated in fresh vegetables which were not irrigated with sewage treatment plant water. Vegetables which were irrigated with waste water from a sewage treatment plant contained equal numbers of the two species. S. faecium survived the effect of chlorination better than S. faecalis. The tendency for chain aggregate formation was more prominent in S. faecalis especially during exponential growth. This affected the recoveries after freezing but not after the chlorination treatment. With exponential cultures which were treated for aggregate dispersal and with stationary cultures, S. faecium survived the effect of freezing better. This indicates a higher resistance of this organism and that the vegetable treatments in the freezing plant may result in a relative enrichment in S. faecium. Thus, enterococcal count in frozen vegetables is comprised to a large extent of this group, a fact which reduces the significance of the enterococci as a sanitary indicator. A specific S. faecalis count may be a better indicator of the sanitary quality of frozen vegetables and may be performed with KF agar supplemented with 0.04% K2 Te03.