等离子体处理对生鲜鱼肉杀菌效能及贮藏品质的影响

Effect of cold plasma on microbial decontamination and storage quality of fish fillets

为探究低温等离子体处理对贮藏过程中生鲜鱼肉品质的影响,该文采用不同电压(40、50、60和70 kV)的介质阻挡放电低温等离子体设备对生鲜鱼肉进行预处理,随后将样品置于4℃、相对湿度为85%的条件下贮藏,检测样品中微生物数量(菌落总数、大肠杆菌总数和假单胞菌总数)及理化品质[颜色、pH、硫代巴比妥酸(thiobarbituric acid,TBA)值、感官品质和组胺含量]在贮藏期间的变化,并分析组胺含量与品质指标的相关性。结果表明,等离子体处理可有效抑制生鲜鱼肉中微生物的增长速度,且处理电压越高,抑制效果越明显。对照组菌落总数在第4天时超过阈值(6 lgCFU/g),40 kV和50 kV处理组到第6天超过阈值,60 kV和70 kV处理组在第8天超标。另外,随着贮藏时间延长,低温等离子体处理会提高样品TBA及感官评分。此外,经等离子体处理后,生鲜鱼肉在贮藏期间组胺积累速率低于对照组,且始终低于国标。皮尔逊相关系数分析结果显示,生鲜鱼肉鱼组胺含量变化与其他品质之间均呈极显著相关(P<0.01)。综上,低温等离子体冷杀菌技术能有效延长鱼肉货架期4 d,同时有助于减少鱼肉组胺积累及维持鱼肉品质;由于生鲜鱼肉在感官可接受范围内存在组胺超标的风险,因此对其进行安全品质评价时应同时结合多个指标判断。

This paper aimed to explore the influence of cold plasma on the quality of fresh fish during storage.Here,grass carp were treated with dielectric barrier discharge(DBD)cold plasma under different voltages(40,50,60,and 70 kV)for 3 min at room temperature,then the samples were stored at 4℃and 85%RH(relative humidity).The number of microorganisms(the total viable counts,the total number of Escherichia coli and Pseudomonas)and physicochemical quality(color,pH,thiobarbituric acid(TBA)value,sensory evaluation and histamine content)of fresh fish were determined during storage.The results showed that the total number of microorganisms in fresh fish meat decreased significantly after plasma treatment(P<0.05),and the bactericidal effect showed an increase as treatment voltage increased.On the 4th day of storage,the total number of bacterial colonies in the control group exceeded the threshold limit value(6 lgCFU/g),the samples after plasma treatment at 40 kV and 50 kV treatment groups exceeded the threshold limit value(6 lgCFU/g)on the 6th day of storage,and the 60 kV and 70 kV treatment groups exceeded the threshold on day 8th.However,the sample treated with 70 kV showed a higher TBA value on the 8th day of storage,TBA values of all groups exceeded the threshold value(0.6 mg/kg).Besides,the histamine accumulation rate of fresh fish during storage was lower than that of the control group after plasma treatment,to be more specific,it was always lower than the national standard.Pearson correlation coefficient analysis showed that the histamine content of fresh fish fillets was significantly correlated with other quality indexes.The above results indicated that plasma cold sterilization technology could effectively prolong the shelf life of fish for 4 d,reduce the accumulation of histamine and maintain the quality of fish.Since there was a risk of histamine exceeding the acceptable range of fresh fish,the safety and quality evaluation of fresh fish should be valued with multiple indicators.In addition,the pH and holding capacity of the fresh fish decreased slightly after plasma treatments,but no significant effect was observed on color.These results showed that DBD cold plasma sterilization technology can effectively extend the shelf life of fish for 2 d with little influence on the quality.