Effect of nisin on the storage of sous vide processed Korean seasoned beef

Seasoned beef called Jangzorim in Korea is produced by boiling in soy sauce, and is a popular food in Korea. The aim of this study is to evaluate the microbial safety and physical qualities of sous vide processed seasoned beef, and the effect of nisin during storage. Sous vide processed packages with or without nisin (100 IU or 500 IU) were stored at 4 °C or 25 °C for 60 days, and samples measured for quality at regular intervals throughout this storage period. In the case of 25 °C storage, the number of mesophilic microorganisms in seasoned beef packages without nisin increased markedly, but with nisin there was no observed increase. Psychrotrophic microorganisms, anaerobic microorganisms, and B. cereus cells showed similar trends, although C. perfringens was not detected in all samples. At 25 °C storage, changes in the cutting force of packages containing nisin showed no significant change, packages without nisin decreased markedly. The colour of packages without nisin showed a drastic decrease in lightness (‘L’) while no changes were observed in packages with nisin.     

INHIBITION OF BEER-SPOILAGE LACTIC ACID BACTERIA BY NISIN

149 strains of bacteria, mostly brewery contaminants able to spoil wort or beer, and 12 brewing strains of yeast (8 ale and 4 lager strains) have been screened using a well-test assay for sensitivity to the food preservative, Nisin (E234), Nisin inhibited growth of 92% of the gram-positive strains, predominantly lactic acid bacteria of the genera Lactobacillus and Pediococcus. In contrast, all 32 gram-negative strains tested, except 3 Flavobacter strains, were Nisin-resistant; in addition none of the brewing yeasts showed Nisin-sensitivity. Therefore. Nisin has potential applications in preventing spoilage of worts or beers by lactic acid bacteria.     

Nisin as a Food Preservative: Part 1: Physicochemical Properties,Antimicrobial Activity,and Main Uses

Nisin is a natural preservative for many food products. This bacteriocin is mainly used in dairy and meat products. Nisin inhibits pathogenic food borne bacteria such as Listeria monocytogenes and many other Gram-positive food spoilage microorganisms. Nisin can be used alone or in combination with other preservatives or also with several physical treatments. This paper reviews physicochemical and biological properties of nisin, the main factors affecting its antimicrobial effectiveness, and its food applications as an additive directly incorporated into food matrices.     

Listeria monocytogenes develops no resistance to ferulic acid after exposure to low concentrations

Antimicrobial agents have been used as additives to control the growth of Listeria monocytogenes. Although nisin has been used to inhibit the growth of L. monocytogenes in food products, exposure to this agent also poses a risk for the development of nisin resistance. Ferulic acid has also been extensively used for growth inhibition of L. monocytogenes, although no previous investigations on the development of ferulic acid resistance have been conducted. In the present study, we inoculated culture media containing one of these two antimicrobial agents with bacteria that had been previously exposed to these agents and assessed for any changes in resistance. The resistance of L. monocytogenes to nisin increased after exposure to 5 ppm nisin, and its survival rate against 20 ppm nisin improved. On the other hand, exposure to 1000 ppm ferulic acid did not increase ferulic acid resistance. The present study demonstrated that the concentration of added nisin must be considered carefully to achieve a sufficient effect. Ferulic acid, on the other hand, showed a minimal risk of producing resistant bacteria, thus allowing it to impart a stable effect.     

冷却肉保鲜剂筛选试验研究

在查阅国内大量文献的基础上,确定了GNa液、Nisin、有机酸等几种国内认为较好的鲜肉生物与化学保鲜剂,并在此基础上设计了GNa-Nisin组、Nisin-Acid组两种新的配方。经试验,GNa液在稳定冷却肉感官指标方面具有较好的效果。但对于抑制脂肪的酸败、控制细菌总数、大肠菌群的增加效果较差。Nisin对于抑制G+细菌的生长有一定的效果,但易使产品出现轻微的异味。本试验中;有机酸有明显抑制大肠菌群的效果,但易使产品出现肉色恶化和明显的异味,也能加深或提高脂肪的酸价和H2S含量;试验还得出多种保鲜液配合使用时产生明显的增效作用,具有较好的抑菌保鲜效果。     

乳链菌肽(Nisin)发酵培养基的优化

以从新鲜牛奶中筛选出的乳酸链球菌KY-2为出发菌株,采用二剂量法检测发酵液中Nisin效价,通过单因子试验和正交设计对该菌株产Nisin发酵培养基进行优化.结果表明:该茵株产Nisin的最适碳源、氮源和磷源组合为(%):蔗糖0.8,蛋白胨2.0,酵母膏1.0,K2HPO4 0.9.优化后效价为957.95 IU/mL,比优化前(812.11 IU/mL)提高了18.0%.     

试论天然抑菌剂乳链菌肽(Nisin)在罐头食品中的应用

根据乳链菌肽(Nisin)对食品中的革兰氏阳性菌有明显的抑制作用的原理，将其应用于肉类罐头、蔬菜罐头中后发现，由于乳链菌肽的良好的抑菌作用，可大大降低罐头食品的杀菌强度，在节约能源的同时，更重要的是提高了产品的品质，保证了产品的安全性。     

植物蛋白类食品保鲜膜特性及保鲜效果的研究

采用国产大豆分离蛋白和谷元粉为原料,制备食品可食保鲜膜,并对膜透性及其抗氧化进行了研究,结果认为这两种植物蛋白具有较好的成膜性的抗氧化性,营养丰富,可食,是制备食品保鲜膜的理想基料,大豆分离蛋白膜的各项性能指标及抗氧化性均优于谷元粉膜。     

乳酸链球菌素在肉制品中的应用

乳酸链球菌素是一种天然、高效、安全的食品防腐剂,其应用越来越广泛.本文综述了乳酸链球菌素的特性及在肉制品中的应用,并对其应用前景进行展望.