软烤扇贝加工过程的细菌学研究

Bacteriological study on the lightly baked processing procedure of scallop

对软烤扇贝加工过程中物料的细菌特性和有关理化特性进行了研究,并对细菌菌群进行了定性和定量分析。结果表明,实验室加工中,水分含量和水分活度(Aw)的降低都主要发生在调味腌制、焙干过程,最终产品水分含量为42%左右,Aw为0.902±0.003。工厂加工在焙干、烤制过程水分含量和Aw的降低较多,成品水分含量为42%左右,Aw为0.910±0.007,控制良好。实验室加工pH下降主要发生在调味腌制过程,产品pH为5.83左右,工厂产品pH没有明显下降,最终pH为6.70左右,不符合标准要求。实验室加工原料菌落总数是(4.47±1.59)×102cfu/g,在调味摆盘和包装过程分别上升到(1.35±0.83)×103cfu/g、(7.30±0.53)×102cfu/g,在焙干、烤制过程分别下降到(5.43±0.67)×102cfu/g、(2.90±0.75)×102cfu/g,二次杀菌冷却后产品菌落总数均小于300 cfu/g。工厂加工原料菌落总数为(9.08±0.20)×103cfu/g,焙干过程上升至(4.69±0.10)×105cfu/g,烤制过程下降到(1.12±0.40)×104cfu/g,包装过程上升至(2.58±0.20)×106cfu/g。二次杀菌冷却后3个产品中,有1个产品细菌总数为340 cfu/g,不符合企业标准要求。实验室烤制冷却后样品的主要菌群为芽孢杆菌,但仍含有小比例的葡萄球菌。二次杀菌冷却后,样品中仅残存芽孢杆菌,无球菌。工厂二次杀菌冷却后样品中主要菌群为芽孢杆菌,但仍含有相当数量的球菌,比例接近1/3,表明其生产过程不良,产品质量安全存在一定的问题。

This project has made study on the bacterial and chemical characteristics of lightly baked scallop. Bacteria colonies have been qualitatively and quantitatively analyzed. The results indicated that the water content and water activities （Aw） of lab product mainly decreased at curing and drying process. The water content and Aw of final product produced by lab were about 42% and 0.902 ± 0.003 respectively. The water content and Aw of plant product mainly decreased at drying and baking process. The water content and Aw of final product produced by plant were about 42% and 0.910 ±0.007 respectively. The decrease in pH value in laboratory processing occurred mainly in curing process and the pH value of final product was about 5.83. The final pH value of plant product was about 6.70 without significant reduction. The total viable counts （TVC） of raw material in lab was （4.47 ± 1.59） × 10^2 cfu/g and TVC increased to （ 1.35 ± 0.83 ）× 10^3 cfu/g, and （7.30 ±0.53） ×10^2 cfufg respectively in curing and packaging process. TVC descended to （5.43±0.67） × 10^2 efufg, and （2.90 ± 0.75 ） × 10^2 efu/g respectively in kiln drying and baking process. And TCV of products after secondary sterilization by lab were all less than 300 cfu/g. TVC of raw material in plant was （9.08±0.20）× 10^3 cfufg and increased to （4.69±0.10） × 10^5 cfu/g in drying process. TVC descended to （ 1.12±0.40） × 10^4 cfu/g in baking process and increased to （2.58±0.20） × 10^6 cfu/g after packaging. In 3 samples after secondary sterilization by plant, TVC of 1 sample was 340 cfu/g and was not up to product criterion. The bacteria colonies in sample after baking and cooling by lab were mainly Bacillus spp. , but there was still a small proportion of Staphylococcus spp.. The bacteria colonies of samples after secondary sterilization by lab were all Bacillus spp. and no cocci. The bacteria colonies of samples after secondary sterilization by plant were mainly Bacillus spp. and considerable amount of cocci had survived. The proportion of cocci was nearly 1/3. It indicated that the process was improper and had some problems in product quality and safety.