有机酸在抑制致病菌方面具有重要的应用价值。该文以大肠杆菌ATCC25922为指示菌,使用微量稀释法和棋盘格法确定多种有机酸及其组合的最小抑菌浓度,半数有效抑菌浓度和联合抑菌指数。并通过对大肠杆菌细胞膜电位和微观形态的观察,研究不同有机酸组合的联合抑菌效应。结果表明,乙酸、乳酸和丁酸的最小抑菌浓度为2 560 μg/mL,柠檬酸和苹果酸的最小抑菌浓度为5 120 μg/mL;乙酸、乳酸、丁酸、柠檬酸和苹果酸的半数有效抑菌浓度分别为1 004.90、1 497.50、964.32、1 406.02、1 727.72 μg/mL。乙酸和乳酸联用表现为相加作用,乙酸、乳酸和第3种有机酸(丁酸、柠檬酸、苹果酸)联用表现为协同作用;有机酸及其组合会导致大肠杆菌膜电位下降,多数菌体出现收缩、弯曲变形。

随着食品工业对产品质量和安全性的要求不断提高,单一防腐剂的使用往往存在局限性,防腐剂联用因其降本增效等优势,具有重大的应用价值。苯乳酸作为当前高效防腐的天然抑菌物质,研究其复配联用效果对其生产应用具有良好意义。该研究采用苯乳酸和肉桂醛联用,以腐败希瓦氏菌为指示菌,通过最小抑菌浓度、复配液联合抑菌浓度指数(fractional inhibitory concentration index,FICI)测定,证明苯乳酸-肉桂醛的联合抑制效果;通过激光共聚焦显微镜、扫描电镜和傅里叶变换红外光谱仪等观察苯乳酸-肉桂醛联用后的抑菌作用机制;基于小牛胸腺DNA(calf thymus DNA,ct-DNA)模型,通过荧光光谱法探究苯乳酸-肉桂醛联用与ct-DNA的结合情况。研究结果表明,苯乳酸对指示菌的最小抑菌质量浓度为2 mg/mL,肉桂醛对指示菌的最小抑菌浓度为0.5 μL/mL,苯乳酸-肉桂醛复配联用的FICI值为0.75,表现出相加作用;激光共聚焦显微镜观察苯乳酸-肉桂醛联用后细胞膜的完整性破坏;扫描电子显微镜研究表明苯乳酸-肉桂醛联用使菌体表面凹陷且内容物流出,菌体断裂严重,有黏连现象,菌体细胞壁遭到破坏;傅里叶红外光谱研究表明苯乳酸-肉桂醛联用破坏了细胞壁和膜上的蛋白质和肽聚糖,破坏了磷脂双分子层;荧光光谱分析表明苯乳酸-肉桂醛联用能与ct-DNA发生沟槽结合。苯乳酸联用肉桂醛起到降本增效作用,同时作用机制表明苯乳酸-肉桂醛联用作用位点处包含细胞壁、膜。该研究基于细胞和分子层面探讨苯乳酸-肉桂醛复配的抑制效果与作用机制,为防腐保鲜剂的开发与应用提供一定的理论基础。

In this study, an active antibacterial packaging film was developed by coating a polyethylene terephthalate/polyvinylidene chloride/retort casting polypropylene (PPR) plastic multilayer film with plantaricin BM-1 and chitosan. The characteristics of the active packaging film and its antibacterial effect for chilled meat preservation were evaluated. Our results indicated that the barrier properties against oxygen were improved significantly and the tensile strength and the elongation at break were changed slightly. The active plantaricin film significantly (P < 0.05) decreased the viable counts of Listeria monocytogenes by 3.6 log CFU/mL in liquid medium and approximately 1.4 log CFU/g in meat stored at 4 °C for 8 days compared with the control. Moreover, the viable counts of aerobes and anaerobes in the meat packaged with the active plantaricin film were significantly (P < 0.05) decreased by approximately 0.6 log CFU/g and 1.1 log CFU/g when compared with that packaged with PPR film stored at 4 °C for 12 days. The total volatile base (TVB-N) in the meat packaged with the active plantaricin film was significantly (P < 0.05) lower than that in the control during the entire storage period. Our results indicated that the active film could extend the meat shelf life by inhibiting the L. monocytogenes and the background spoilage bacteria in chilled meat stored at 4 °C. This outcome suggests that plastic multilayer film incorporating plantaricin BM-1 can be potentially used for fresh meat packaging. PRACTICAL APPLICATION: Fresh meat is highly perishable product. This study developed a plantaricin BM-1 active plastic multilayer film that can inhibit the growth of microorganisms in chilled meat during storage at 4 °C.© 2019 The Authors. Journal of Food Science published by Wiley Periodicals, Inc. on behalf of Institute of Food Technologists®.

Food safety is a global health and socioeconomic concern since many people still suffer from various acute and life-long diseases, which are caused by consumption of unsafe food. Therefore, ensuring safety of the food is one of the most essential issues in the food industry, which needs to be considered during not only food composition formulation but also handling and storage. For safety purpose, various chemical preservatives have been used so far in the foods. Recently, there has been renewed interest in replacing chemically originated food safety compounds with natural ones in the industry, which can also serve as antimicrobial agents. Among these natural compounds, organic acids possess the major portion. Therefore, in this paper, it is aimed to review and compile the applications, effectiveness, and microbial productions of various widely used organic acids as antimicrobial agents in the food industry.