Cold plasma treatment for microbial safety and preservation of fresh lettuce

Abstract

Cold plasma treatment (CPT) was investigated for inhibition of foodborne pathogens and extension of fresh lettuce storage life. Lettuce samples were treated with CP at 400 W and 900 W for 10 min for assessment of the effects of CPT on inhibition of Escherichia coli O157:H7 and Salmonella Typhimurium, and on physicochemical and sensory properties of lettuce. N2, an N2-O2 mixture, and He effectively formed CP against both pathogens. CPT inhibited both pathogens on lettuce by up to 2.8 log CFU/g. The Weibull model adequately described the degree of microbial inhibition using CPT. N2-CPT did not affect the sensory properties of lettuce. N2-CPT resulted in a bacteriostatic effect against growth of E. coli O157:H7 but did not affect physicochemical properties of lettuce during storage. CPT demonstrated potential for improving the microbial safety of vegetables without loss of physicochemical or sensory properties.