BIOGENIC-AMINE CONTENT AND MICROBIAL-CONTAMINATION OF LEAFY VEGETABLES DURING STORAGE AT 5C

Biogenic amine content and microbial contamination of prepacked salad mixtures and the fresh leafy vegetables Chinese cabbage (Brassica peki nensis Rupr.), endive (Cichorium endivia L.), iceberg lettuce (Lactuca sativa var. capitata) and radicchio (Cichorium intybus var. foliosum) were examined during storage at 5C for 6 days. Putrescine, histamine, spermidine, spermine and tyramine were detected in concentrations ran ging from 0. 1 to 17 mug/g fresh weight. Only putrescine showed a prog ressive increase during storage, depending on the type of leafy vegeta ble; its level of increase ranged from 3- to 8-fold, with the most pro nounced for Chinese cabbage. A relationship seems to exist between the Enterobacteriaceae population (representing up to 90% of the total mi crobial numbers determined by plate count methods) and the putrescine concentration.