Quality changes and construction of shelf life prediction model about microbial of fresh-cut leafy vegetables

In order to study the changes in the quality of fresh- cut cabbage and fresh- cut lettuce during storage and predict the shelf life,fresh- cut cabbage and fresh- cut lettuce were researched on their quality and microbial indicators,including colony- forming unit( CFU) and the number of coliform bacteria.With CFU as the independent variable,the shelf life prediction models at 4 ℃ and 25 ℃ were calculated. The results showed that when stored after 10 d and 3 d at 4 ℃ and 25 ℃ respectively,the quality evalution were reached at 5,which were unacceptable to consumers; and the number of total bacterial count and coliform bacteria beyond standards.According to these indicators,the shelf life were found out to be 10 d and 3 d at 4 ℃ and 25 ℃ separately. The shelf life prediction models at 4 ℃ and 25 ℃ were SL_(4℃)=ln｛ln5.096/(N_1-1.990)｝-1/0.279+7.452 and SL_(25℃)=ln｛ln3.621/(N_1-3.651)-1/1.124+1.512,respectively.The deviation factor,0.979 and 1.001,and accurate factor,1.050 and 1.040,showed that the models were effective.They provided a theoretical basis for the calculation of shelf life of fresh- cut cabbage and fresh- cut lettuce.