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MODEL OF MICROBIAL GROWTH ON FRESH‐CUT LETTUCE TREATED WITH CHLORINATED WATER DURING STORAGE UNDER DIFFERENT TEMPERATURES
Author(s) -
LU ZHAOXIN,
ZHANG LIKUI,
LU FENXIA,
BIE XIAOMEI,
YU ZHIFANG
Publication year - 2007
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/j.1745-4530.2007.00091.x
Subject(s) - gompertz function , shelf life , bacteria , bacterial growth , postharvest , horticulture , chemistry , food science , biology , mathematics , statistics , genetics
Various Gompertz models of the growth of bacteria on fresh‐cut lettuce were established in order to predict the shelf life of fresh‐cut lettuce untreated and treated with chlorinated water in storage under different temperatures. The sensory quality of fresh‐cut lettuce treated with water containing 75 µ g/L of available chlorine was also examined during storage at 0, 4 and 25C, respectively. Bacteria growth on fresh‐cut lettuce in storage was analyzed to evaluate the effect of temperature, and the established model of predictive bacteria growth on fresh‐cut lettuce fitted the Gompertz modified model best. The lag time λ , the asymptote A and maximum specific growth rate μ m of the bacteria were calculated, according to Gompertz models. The value of μ m and A at 0C were lower than that at 4 and 25C, and the lag time was longer at a low temperature than at a higher temperature, indicating that the lower the storage temperature, the slower the growth of bacteria on lettuce, and the smaller the maximum bacteria number reached on the lettuce. The efficacy of preservation of fresh‐cut lettuce treated with chlorinated water was significantly better than that of nontreated lettuce under the same storage temperature. It was found that the final bacteria number predicted ( S ) on lettuce treated with chlorinated water was lower than that on nontreated lettuce, and that the higher the storage temperature, the higher the final bacteria number predicted ( S ). The established growth models at different temperature were able to predict the shelf life of fresh‐cut lettuce.