Low-dose irradiation of cut iceberg lettuce in modified atmosphere packaging.

Irradiation at a mean dosage of 0.19 kilogray of commercially prepared fresh-cut lettuce (cultivars Raleigh and Patriot) resulted in a product that had, 8 days after irradiation, a microbial population of 290 cfu/g and a yeast population of 60 cfu/g, compared with values of 220,000 and 1,400 cfu/g, respectively, for the non-irradiated control. Irradiation also caused moderate changes in respiration rate and headspace gas concentrations. The results suggest that it is feasible to combine chlorination with irradiation to produce fresh-cut, chopped lettuce with a reduced microbial population.