Effectiveness of organic acid, ozonated water and chlorine dippings on microbial reduction and storage quality of fresh-cut iceberg lettuce
2007
Akbas, Meltem Yesilcimen | Ölmez, Hülya
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.
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