2种耐压菌对盐水鸭货架期的影响

Effects of two pressure-resistant bacteria on the shelf-life of water-boiled salted duck

将前期研究分离得到的2种耐压菌蜡状芽孢杆菌(Bacillus cereus)和沃氏葡萄球菌(Staphylococcus warneri)接种至盐水鸭胸肉中,以贮藏过程中理化性质的变化为指标,评价2种耐压菌对真空包装盐水鸭货架期的影响。结果表明:2种细菌在盐水鸭胸肉中表现出很强的生长能力;由Gompertz方程得到沃氏葡萄球菌和蜡状芽孢杆菌的生长动力学参数,最大比生长速率分别为0.257 5和0.473 3 h-1,延滞时间分别为5.1和11.2 h,最大菌落数分别为7.18和6.53 lg(CFU·g-1);在盐水鸭菌落总数的可接受范围内(<4.9 lg(CFU·g-1)),2种耐压菌对盐水鸭胸肉贮藏过程中的pH值及挥发性盐基氮(TVB-N)值影响较小,其致腐能力较弱;在60 h时(即菌落总数达到6 lg(CFU·g-1)),蜡状芽孢杆菌对盐水鸭胸肉气味影响较大,接种该菌的样品与对照组样品的气味存在显著差别。结论:耐压菌快速生长导致菌落总数超标可使货架期缩短,因此,控制耐压菌的快速生长是确保盐水鸭货架期的关键因素。

Two pressure-resistant bacteria, isolated from high pressure treated water-boiled salted duck, were inoculated in the breast of the duck. The effect of the two bacteria on the shelf-life of the breast was analyzed. The results showed that the bacteria displayed strong growth activity in water-boiled salted duck. Adopting Gompertz regression equation to describe the growth curve of Staphylococcus warneri and Bacillus cereus, we gained the grow kinetics model parameters. The maximum specific growth rate of Staphylococcus warneri and Bacillus cereus were 0. 257 5 h^-1 and 0. 473 3 h^-1 , the lag time were 5.1 h and 11.2 h, the maximum numbers of bacteria were 7.181g（ CFU. g^-1 ） and 6.53 lg（ CFU· g^-1 ）, respectively. However, when the total number of colonies was at acceptable range（ 〈4. 9 lg（ CFU.g^-1） ）,there was no significant difference between control and treatment samples of pH value and total volatile basic nitrogen（TVB-N） value. Bacillus cereus had a significant impact on the odor, at 60 h（ the total number of colonies reached 6 1g（ CFU.g^-1 ） ） ,and samples treated with Bacillus cereus could be separated completely from the controls. In conclusion, the rapid growth of the pressure-resistant bacteria, which caused the total number of colonies to exceed the hygienic standard, would shorten the shelf life of the samples. Therefore, controlling the rapid growth of the pressure-resistant bacteria is a key factor in ensuring the shelf life of salted duck.