Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 23, 2007
Publication Date: October 30, 2007
Citation: Kim, J., Tao, Y., Luo, Y. 2007. Effect of the combination treatment of 1-methylcyclopropene and acidified sodium chlorite on microbial growth and quality of fresh-cut cilantro. Postharvest Biology and Technology. 144-149.
Interpretive Summary: There is an increased consumer demand for packaged fresh-cut culinary herbs, especially cilantro, in both retail and food service sectors. However, the large microbial populations present on cilantro leaves and the rapid quality deterioration remain important obstacles to overcome. We investigated the effects of 1-methylcyclopropene (1-MCP; a chemical substance that blocks the harmful effect of an age-related plant hormone) and acidified sodium chlorite (ASC; a new sanitizer with a strong killing effect on human pathogenic bacteria and spoilage microorganisms) on quality maintenance and microbial reduction in fresh-cut cilantro. We found that the combined treatment of 1-MCP and ASC was effective in maintaining quality and safety of fresh-cut cilantro. Fresh-cut cilantro that received the combination treatment had the lowest bacterial populations and coliform/Escherichia coli counts, lowest rate of decay, and best overall quality during storage. These findings are important to the fresh-cut industry for solving technical obstacles in developing new products containing fresh-cut cilantro that meet their quality and safety standards.
Prior research has shown that 1-methylcyclopropene (1-MCP) binds to ethylene receptors blocking ethylene activity and can, therefore, be used effectively to delay senescence of tissues in many fruits and vegetables. Acidified sodium chlorite (ASC) has been used effectively as a sanitizing agent to inhibit microbial growth on fruits and vegetables. The authors hypothesize that the combined application of 1-MCP and ASC would be a beneficial treatment to increase shelf-life and improve the quality and safety of fresh-cut cilantro (Coriandrum sativum L.). This study investigated the effects of 1-MCP, ASC, and their combination on respiration rate and ethylene production, microbial growth and storage life of fresh-cut cilantro. Cilantro bunches were treated with 1.5 µl•L-1 1-MCP for 18 h at 10 °C. The treated and non-treated cilantro leaves were cut and washed in water, 100 µl•L-1 chlorine, or 100 µl•L-1ASC solutions. Samples were centrifugally dried, packaged with 29.2 pmol s-1 m-2 Pa-1 oxygen transmission rate films, and stored for 14 days at 5 °C. Results indicated that 1-MCP reduced the respiration rate of fresh-cut cilantro and significantly (P < 0.0001) delayed the decrease in oxygen and accumulation of carbon dioxide partial pressures in the headspace of sample packages, and also retained a lower tissue electrolyte leakage. ASC application resulted in a significant reduction of initial aerobic bacterial populations and coliform/Escherichia coli counts, and significantly reduced the rate of decay. Combined treatment with 1-MCP and ASC was effective in maintaining tissue integrity, reducing ethanol production, reducing decay and maintaining the highest overall quality at the end of storage.