Effectiveness of organic acid, ozonated water and chlorine dippings on microbial reduction and storage quality of fresh-cut iceberg lettuce

• Published in: Journal of the science of food and agriculture 2007-11, Vol.87 (14), p.2609-2616
• Main Authors: Akbas, Meltem Yesilcimen, Ölmez, Hülya
• Format: Article
• Language: English
• Subjects: acid treatment; aqueous solutions; bacteria; bacterial contamination; Biological and medical sciences; chlorine; citric acid; dipping; Enterobacteriaceae; Fatty acids; Food contamination & poisoning; Food industries; food microbiology; Food preservation; Food safety; fresh-cut; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; head lettuce; lactic acid; Lactuca sativa var. capitata; Lettuce; organic acids; ozonation; Ozone; postharvest treatment; psychrotrophic bacteria; shelf life; storage quality
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.3016

BACKGROUND: The comparative effects of organic (citric and lactic) acids, ozone and chlorine on the microbiological population and quality parameters of fresh-cut lettuce during storage were evaluated.RESULTS: Dipping of lettuce in 100 mg L⁻¹ chlorine solution reduced the numbers of mesophilic and psychrotrophic bacteria and Enterobacteriaceae by 1.7, 2.0 and 1.6 log₁₀ colony-forming units (CFU) g⁻¹ respectively. Treatment of lettuce with citric (5 g L⁻¹) and lactic (5 mL L⁻¹) acid solutions and ozonated water (4 mg L⁻¹) reduced the populations of mesophilic and psychrotrophic bacteria by 1.7 and 1.5 log₁₀ CFU g⁻¹ respectively. Organic acid dippings resulted in lower mesophilic and psychrotrophic counts than ozonated water and chlorine dippings during 12 days of storage. Lactic acid dipping effectively reduced (by 2.2 log₁₀ CFU g⁻¹) and maintained low populations of Enterobacteriaceae on lettuce for the first 6 days of storage. No significant (P > 0.05) changes were observed in the texture and moisture content of lettuce samples dipped in chlorine, organic acids and ozonated water during storage. Colour, β-carotene and vitamin C values of fresh-cut iceberg lettuce did not change significantly (P > 0.05) until day 8.CONCLUSION: Lactic and citric acid and ozonated water dippings could be alternative treatments to chlorine dipping to prolong the shelf life of fresh-cut iceberg lettuce. Copyright © 2007 Society of Chemical Industry