Microbiological and Organoleptic Quality of Fresh-Cut Vegetables Treated with Disinfectants and Stored in High CO2atmospheres

Microbiological and organoleptic quality of fresh-cut lettuce, spinach, carrots, and Japanese radish was evaluated after treatments with disinfectants and stored in high CO₂ atmospheres (10%, 15%, and 20%) at 10°C. The samples were initially treated with a 1% fumaric acid agent (0.2% of fumaric acid), 2% calcined calcium agent (0.1% of calcium oxide), or 5% alcohol agent (0.25% of ethyl alcohol) with subsequent washing with electrolyzed water containing 10 ppm available chlorine. Among the antimicrobial agent treatments combined with electrolyzed water, fumaric acid agent applied on fresh-cut lettuce, alcohol agent on fresh-cut spinach and carrots, and calcined calcium agent on fresh-cut Japanese radish reduced the bacterial counts by 0.8 to 1.5 logs relative to water-dipped control. Treatments had minimal effect on organoleptic quality including wilting, browning, and water-soaked appearance. When fresh-cut vegetables treated with each optimum disinfectant were stored in air or high CO₂ atmospheres at 10°C for 6 days, high CO₂ of >10% reduced growth of mesophiles or coliforms by 0.5 to 2 logs as compared to those in air and limited the diversity of bacterial flora comprising phytopathogenic organisms such as genera Enterobacter, Pantoea, and Pseudomonas with all fresh-cuts. However, the 15% and 20% CO₂ atmospheres accelerated growth of lactic acid bacteria with fresh-cut spinach, carrots, and Japanese radish, which contributed to detrimental effect on the organoleptic quality such as off-odor. Therefore, a 15% CO₂ for fresh-cut lettuce and 10% CO₂ for fresh-cut spinach, carrots, and Japanese radish would be recommended for the storage of product after disinfectant treatments.