SUMMARY Bacteria occur within normal, sound fresh fruit tissues. They are mostly gram‐negative motile rods, representatives of the Pseudomonadaceae and the Enterobacteriaceae. Lactic‐acid‐forming bacteria are found on the surface of crops. In different crops and in different varieties, bacteria may appear abundantly in one field and rarely in others. They are found more frequently in low‐growing vegetables than in tree borne fruits. In cucumbers the bacteria are more often in the tissue close to the periphery and less often in the central core. In tomatoes their frequency is highest close to the stem‐scar and the central core of the fruit, decreasing toward the fruit periphery. It appears that the bacteria can enter the living plant tissue by different pathways and may persist there as harmless commensals. When the vegetables are brined, the bacteria multiply in the tissue as well as in the brine. Lactobacilli penetrate gined tomatoes primarily through the stem‐scar and multiply more rapidly in the fruit than in the brine. During fermentation of tomatoes and cucumbers the Enterobacteriaceae are mostly Suppressed by the lactic‐acid‐forming bacteria. However, if the latter are excluded by surface disinfection of the fruits, the Enterobacteria continue to multiply, causing internal bloaters, an increase in pH, and, ultimately, putrefaction.

where they are applicable. Preliminary isolation on solid media is mandatory where a classification of species or groups is intended to eliminate possible overgrowths by certain streptococcal strains. REFERENCES COOPER, K. E. AND LINTON, A. H. 1947 The value of thallium acetate for the isolation of genococci and streptococci. Monthly Bull. Ministry Health Service, 6, 204. FLEMING, A. 1932 On the specific antibacterial properties of penicillin and potassium tellurite. J. Pathol. Bacteriol., 35, 831. HAJNA, A. A. 1951 A buffered azide glucose-glycerol broth for the presumptive and confirmative tests for fecal streptococci.

Bacteria have been shown to be present in fresh normal tomatoes. The frequency of their presence differed widely between different fields. Bacterial populations within the tomatoes showed a distinct gradient, being largest in the connective tissue at the stem end and decreasing through the central core towards the peripheral and distal tissue. Application of Serratia to the sepals of young tomato fruits often resulted in their recovery from within tissue of the mature fruit. These findings lend support to the theory that the bacteria enter the fruit through the connective tissue at the stem end.

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