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Effect of controlled athmosphere storage,modified athmosphere packaging and gaseous ozone treatment on the survival characteristics of Salmonella enteritidis ay cherry tomatoes

Daş, Elif
In recent years, outbreaks of infections associated with raw and minimally processed fruits and vegetables have been reported. Possible sources for contamination are irrigation water, manure, wash water, handling by workers and contact with contaminated surfaces. Pathogens can occur on raw and minimally processed produce at populations ranging from 103 to 109 CFU/g and able to survive and sometimes grow under various storage conditions. The objective of this study was to analyse the growth/survival of Salmonella Enteritidis at spot-inoculated or stem-injected cherry tomatoes during passive modified atmosphere packaging (MAP), controlled atmosphere (CA) and air storage at 7 and 22°C. Low density polyethylene (LDPE) with a package size of 10x10 cm2 for 25±2 g tomatoes was used for MAP storage in which the gas composition equilibrated to 6% O2/ 4% CO2 and a carbon dioxide incubator was used for CA storage in which the CO2 level was monitored and maintained as 5% through the term of storage at 7 and 22°C. During the research, the effect of ozone treatment (5-30 mg/L ozone gas for 0-20 min) was also considered for surface sanitation. The results demonstrate that S.Enteritidis can survive and/or grow during the storage of tomatoes depending on the location site of the pathogen on fruit, suspension cell density and storage temperature. During MAP, CA and air storage, S.Enteritidis with initial population of 7.0 log10 CFU/tomato survived on tomato surfaces with an approximate decrease of 4.0-5.0 log10 CFU/tomato in population within the storage period; however, in the case of initial population of 3.0 log10 CFU/tomato, cells died completely on day 4 during MAP storage and on day 6 during CA and air storage. The death rate of S.Enteritidis on the surfaces of tomatoes that were stored in MAP was faster than that of stored in air. Storage temperature was effective on the