Bacteriological quality assessment of fresh marketed lettuce and fennel

Abstract

One-hundred and twenty samples of lettuce and 89 samples of fennel purchased from five retail outlets in the city of Bari (Italy) from October 1973 through September 1975 were examined for viable aerobic bacteria (AB), total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS), and salmonellae. Comparative tests indicated that the results of bacteriological analysis of wash water from either vegetable by a membrane filter technique compared favorably with those of conventional cultural examination of the vegetable tissue for the purpose of providing an indication of the bacteriological quality of the samples. Using the membrane filter technique, 2-year average counts of 6.59 X 10(7) for AB, 5.95 X 10(4) for TC, 6.13 X 10(3) for FC and 2.24 X 10(3) for FS/100 g (fresh weight) were obtained with lettuce; with fennel, the corresponding figures were 2.32 X 10(6) for AB, 7.82 X 10(4) for TC, 7.8 X 10(4) for FC, and 3.15 X 10(3) for FS. Indicator bacteria were present in all samples examined. In addition, 68.3% of the lettuce and 71.9% of the fennel samples yielded one or more of the following Salmonella serotypes: S. schottmuelleri, S. typhimurium, S. thompson, S. dublin, S. typhi, and S. anatum.