基于宏基因组技术的生鲜乳中耐热酶污染来源分析  

Analysis of Pollution Source of Thermostable Enzymes in Raw Milk Based on Metagenomic Technology

作　　者：代良超 逄晓阳[2] 胡少震 喻东威[3] 吕加平[2] 逯刚 武俊瑞[1] 张书文[2] Dai Liangchao;Pang Xiaoyang;Hu Shaozhen;Yu Dongwei;LüJiaping;Lu Gang;Wu Junrui;Zhang Shuwen(College of Food Science,Shenyang Agricultural University,Shenyang 110866;Institute of Food Science and Technology,Chinese Academy of Agricultural Sciences,Beijing 100193;Inner Mongolia Meng Niu Dairy(Group)Co.,Ltd.,Hohhot 011517;College of Life Sciences and Technology,Tarim University,Alaer 843300,Xinjiang)

机构地区：[1]沈阳农业大学食品学院,沈阳110866 [2]中国农业科学院农产品加工研究所,北京100193 [3]内蒙古蒙牛乳业(集团)股份有限公司,呼和浩特011517 [4]塔里木大学生命科学与技术学院,新疆阿拉尔843300

出　　处：《中国食品学报》2024年第8期448-456,共9页Journal of Chinese Institute Of Food Science and Technology

基　　金：国家现代农业产业技术体系(CARS-36);宁夏重点研发计划项目(2021BEF02022);内蒙古科技计划项目(2021GG0368)。

摘　　要：生鲜乳中的耐热酶会严重影响产品货架期的质量稳定性,而耐热酶的主要来源和污染途径一直存在争论。基于宏基因组技术分析中国某牧场的环境样本(牛舍垫土、TMR饲料)和生鲜乳样本(头三把奶、头三把奶之后生鲜乳、储奶罐中生鲜乳)的微生物群落组成及其产胞外蛋白酶(EC 3.4.24.40)和脂肪酶(EC 3.1.1.3)的基因丰度,弄清储奶罐中生鲜乳的耐热酶污染来源。多样性分析结果表明:牛舍垫土中的典型嗜冷菌丰富度,如假单胞菌属(1.57%)和不动杆菌属(1.56%)远高于其它样品,远高于头三把奶(0.26%,0.54%)。通过微生物产酶基因分析,储奶罐中生鲜乳中产生耐热酶的微生物主要来自嗜冷菌,为假单胞菌属和不动杆菌属。各样本中产蛋白酶的基因丰度为:牛舍垫土:8.71、头三把奶:0.18;产脂肪酶各的基因丰度为:牛舍垫土:16.19、TMR饲料:0.33、头三把奶:0.18、头三把奶之后生鲜乳:0.39、储奶罐中生鲜乳:0.22。此外,储奶罐中生鲜乳的脂肪酶基因在挤奶环节中基因重复率最低为57.14%。因此,微生物及其嗜冷菌通过牛舍垫土污染奶牛乳头,在挤奶环节会进入生鲜乳收集管路而造成污染。本研究为有效防控生鲜乳中耐热酶的污染提供了理论和数据基础。Thermostable enzymes in raw milk can seriously affect the quality stability of the shelf life of products.However,the main sources and contamination pathways of thermostable enzymes have been debated.In this study,metagenomic technology was performed to analyze the microbial community composition and gene abundance of extracellular protease(EC 3.4.24.40)and lipase(EC 3.1.1.3)in environmental samples(barn bedding soil,TMR feed)and fresh milk samples(the first three milk,after the first three of milk,and raw milk of storage tank)from a farm in China.This study aimed to investigate the source of thermostable enzyme contamination of raw milk in milk storage tanks.The results of diversity analysis showed that the abundance of typical psychrophilic bacteria such as Pseudomonas(1.57%)and Acinetobacter(1.56%)in the barn bedding soil was much higher than that of the other samples.It was much higher than the first three milk(0.26%,0.54%).Through gene analysis of microbial enzyme production,the microorganisms that thermostable enzymes in raw milk of storage tank were mainly from psychrophilic bacteria,Pseudomonas and Acinetobacter.The abundance of extracellular protease-producing genes in each sample was barn bedding soil:8.71 and the first three milk:0.18;the abundance of extracellular lipase-producing genes in each was barn bedding soil:16.19,TMR feed:0.33,the first three milk:0.18,after the first three of milk:0.39 and raw milk of storage tank:0.22.In addition,the lipase gene of raw milk in storage tanks had the lowest gene duplication of 57.14%during the raw milk collection line.In addition,microorganisms and their psychrophilic bacteria contaminate the teats of cows through barn bedding soil.Then,they enter the raw milk collection line and cause contamination during milking.This study provided a theoretical and data basis for the effective prevention and control of thermostable enzymes contamination in raw milk.

关 键 词：生鲜乳 宏基因组 嗜冷菌 耐热酶 污染来源 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]