Inactivation of Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes on the surface of tomatoes by neutral electrolyzed water

Abstract

Aims:To determine the efficacy of neutral electrolyzed water (NEW) in killing Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes, as well as nonpathogenic E. coli, on the surface of tomatoes, and to evaluate the effect of rinsing with NEW on the organoleptic characteristics of the tomatoes. Methods and Results:The bactericidal activity of NEW, containing 444 or 89 mg l )1 of active chlorine, was evaluated over pure cultures (8AE5 log CFU ml )1 ) of the above-mentioned strains. All of them were reduced by more than 6 log CFU ml )1 within 5 min of exposure to NEW. Fresh tomatoes were surface-inoculated with the same strains, and rinsed in NEW (89 mg l )1 of active chlorine) or in deionized sterile water (control), for 30 or 60 s. In the NEW treatments, independent of the strain and of the treatment time, an initial surface population of about 5 log CFU sq.cm )1 was reduced to <1 log CFU sq.cm )1 , and no cells were detected in the washing solution by plating procedure. A sensory evaluation was conducted to ascertain possible alterations in organoleptic qualities, yielding no significant differences with regard to untreated tomatoes. Significance and Impact of the Study: Rinsing in NEW reveals as an effective method to control the presence of E. coli O157:H7, S. enteritidis and L. monocytogenes on the surface of fresh tomatoes, without affecting their organoleptic characteristics. This indicates its potential application for the decontamination of fresh produce surfaces.

Biochemical, microbiological and physiological changes in Jamun (Syzyium cumini L.) kept for long term storage under modified atmosphere packaging

“…Texture evaluation was carried out using: 5 = very firm, 4 = firm, 3 = slightly wilted, but acceptable, 2 = wilted, 1 = very much wilted. Visual appearance was scored as per Deza et al (2003) using: 5 = very good, 4 = good, 3 = normal, 2 = limited quality and 1 = not acceptable. Disease severity was assessed as per the method of Burton et al (1987), as utilised with appropriate modifications for this work: 5 = severely diseased, 4 = diseased, 3 = moderately diseased, 2 = slightly diseased and 1 = no disease.…”

Biochemical and physiological changes in Fenugreek (Trigonella foenum- graecum L.) leaves during storage under modified atmosphere packaging

“…Aroma was evaluated as per the scale: 5 = no off-odour, 4 = very light off-odour, 3 = light off-odour, 2 = medium off-odour and 1 = strong off-odour. Visual appearance was scored as per Deza et al (2003) using: 5 = very good, 4 = good, 3 = normal, 2 = limited quality and 1 = not acceptable. Another nine point scale; 0 = vegetable completely wet and water accumulation; 1 = vegetable and film moderately wet; 3 = vegetable moderately wet; 5 = vegetable and film slightly wet; 7 = vegetable slightly wet; 9 = no water accumulation was used to represent the water vapour accumulation inside the film packages (Rai et al 2009a).…”

Impact of Food Disinfection on Beneficial Biothiol Contents in Vegetables

“…For example, chlorine has been routinely used for disinfection of vegetables such as lettuce, carrots, and spinach (12,20,21), fruits such as strawberries, apples, cantaloupe, honeydew melons, and tomatoes (22)(23)(24)(25)(26), chicken (27), and fish (28). A recent progress in chlorine disinfection is the generation of chlorine water through electrolysis (29,30).…”