Abstract

T. S. Workneh , G. Osthoff and M. S. Steyn

Preharvest ComCat® treated tomatoes and untreated controls were evaluated for changes in physiological and microbiological quality characteristics during storage at 13°C and room temperature (16.9 to 25.2°C) and a relative humidity of 34 to 76% after 8, 16, 24 and 30 days. The effectiveness of modified atmosphere packaging (MAP) in Xtend® film, disinfection treatments with chlorine or anolyte water and different storage temperatures were also evaluated. The O2 and CO2 concentrations remained above 15% and below 6% during storage, respectively. MAP retained ascorbic acid and slightly suppressed growth of microorganism. Storage temperature was the most dominant factor. Faster ripening of tomatoes at room temperature was accompanied by rapid changes in O2 and CO2 and faster growth of populations of microorganism. Disinfecting treatments significantly reduced microorganisms. Chlorine disinfection resulted in higher O2 consumption and CO2 production than anolyte water. ComCat® treated tomatoes had lower levels of ascorbic acid and microbial populations, than controls. ComCat® treatment had a significant effect on O2 and N2 concentrations, ascorbic acid, bacteria, moulds and yeasts, and coliform bacteria during storage. During storage at room temperature, the headspace of packages of ComCat® treated tomatoes had higher O2, lower CO2 and lower N2 contents, which indicated a lower respiration rate, compared to controls. During storage, the ascorbic acid content was better retained in ComCat® treated tomatoes than in control tomatoes.