Monitoring of microbiological parameters during the shelf-life of bagged baby-leaf lettuce and rocket

The microbiological parameters of pack- aged baby-leaf lettuce and rocket were monitored in order to evaluate the effect of the length of storage at the temperature of 7°C in two seasons. The count of total aerobic bacteria, coliforms, E. coli, yeasts and moulds was detected at the 2nd, 6th and 8th day of storage, in the spring and summer. The 2nd day the mean of bacteria was 4.49·106 and 1.67·107 cfu·g-1 for lettuce and rocket respectively in the spring and 8.80·106 and 0.98·107 cfu·g-1 respectively in the sum- mer. A significant increase was observed at the 6th and 8th day of storage at 7°C in the spring, at the 8th day in the summer. The mean of coliforms the 2nd day was 8.8·104 and 2.6·104 cfu·g-1 for lettuce and rocket with an increase during the storage. E. coli was detected from a group of lots (13.3% of total) indipen- dently from the storage. The count of yeasts and moulds did not change during the storage and the average of fungal contaminants was higher in rocket (104 cfu·g-1) than lettuce (102 cfu·g-1).