Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 4

Search results for: nisin

4 Antibacterial Activity of Nisin: Comparison the Role of Free and Encapsulated Nisin to Control Staphylococcus Aureus Inoculated in Minced Beef

Authors: Zh. Ghasemi, S. Nouri Saeedlou, A. Ghasemi, SL. Nasiri, P. Ayremlou, P. Mahasti

Abstract:

The use of nisin is successfully used as antibacterial agent in various food products. Although the conclusions of the previous studies were that nisin is not very effective in meat environments. The reduced antimicrobial efficacy of nisin when applied in food has been frequently observed. The aim of this study is to evaluate the potential of free and encapsulated nisin to inhibit the growth of staphylococcus aureus in minced beef. The minimum inhibitory concentration (MIC) of nisin is determined against S. aureus using the agar dilution method. Nisin is encapsulated by spray drying, and encapsulation efficiency, mass yield and total solids content values are 47.79%, 61%, and 96.41 respectively. The study in vitro release kinetics shows highest release of nisin from zein capsules is obtained after 72 hour. This work shows that an appropriate delivery system is necessary to obtain desirable effect of nisin in meat and meat product.

Keywords: nisin, encapsulation, Staphylococcus aureus, minced beef, antibacterial activity

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3 Enhanced Production of Nisin by Co-culture of Lactococcus Lactis Sub SP. Lactis and Yarrowia Lipolytica in Molasses Based Medium

Authors: Mehdi Ariana, Javad Hamedi

Abstract:

Nisin is a commercial bacteriocin that is used as a food preservative and produced by Lactococcus lactis subsp. lactis. Nisin production through co-culture fermentation can be performed for increasing nisin quantities. Since lactate accumulation in the fermentation medium can prevent L. lactis growth and therefore reduce nisin production, the simultaneous culture of microorganisms can enhance L. lactis growth by a reduction in the amount of lactic acid. In this study, conducted coculture of L.lactis subsp. lactic and the yeast Yarrowia lipolytica. Both strains are cultured in a molasses-based medium that is mainly constructed of sucrose. Y. lipolytica is not able to use sucrose as a carbon source but is able to consume lactate and decrease lactic acid in the medium. So, Lactic acid consumption can increase pH value and stimulate L. lactis growth. The results showed the mixed culture increased L. lactis growth 6 times higher than that of pure culture and could enhance nisin activity by up to 40%.

Keywords: co-culture fermentation, lactococcus lactis subsp lactis, yarrowia lipolytica, nisin

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2 Optimizing the Nanoliposome of Nisin Produced by Sonication

Authors: Seyed Moslemi S. A. , Hesari J., Valizadeh H., Rezaiee-Mokaram R.

Abstract:

Nanotechnology and nanoscience and related fields in this area, will impact on daily human life in the not too distant future. The basic materials of liposomes are lipids. Lipids that can be used to build liposomes can be provided from variety of sources. In this research, lecithin and cholesterol were used to prepare liposomes. Probe sonicator was used to minimize the particles of liposome and make nanoliposomes. Encapsulation efficiency were analyzed with pyrogallol red indicator and autoanalizer equipment. The smallest particle size was 220 nanometer( 100 mg lecithin, 50 mg cholestrol, 12 min and amplitude of 90%). The highest encapsulation efficiency was 13.5%( 120 mg lecithin,45 mg cholestrol, 12 min and ampilitude of 92%).

Keywords: optimizing, nanoliposome, nisin, cheese

Procedia PDF Downloads 402
1 Immuno-Protective Role of Mucosal Delivery of Lactococcus lactis Expressing Functionally Active JlpA Protein on Campylobacter jejuni Colonization in Chickens

Authors: Ankita Singh, Chandan Gorain, Amirul I. Mallick

Abstract:

Successful adherence of the mucosal epithelial cells is the key early step for Campylobacter jejuni pathogenesis (C. jejuni). A set of Surface Exposed Colonization Proteins (SECPs) are among the major factors involved in host cell adherence and invasion of C. jejuni. Among them, constitutively expressed surface-exposed lipoprotein adhesin of C. jejuni, JlpA, interacts with intestinal heat shock protein 90 (hsp90α) and contributes in disease progression by triggering pro-inflammatory response via activation of NF-κB and p38 MAP kinase pathway. Together with its ability to express in the bacterial surface, higher sequence conservation and predicted predominance of several B cells epitopes, JlpA protein reserves its potential to become an effective vaccine candidate against wide range of Campylobacter sps including C. jejuni. Given that chickens are the primary sources for C. jejuni and persistent gut colonization remain as major cause for foodborne pathogenesis to humans, present study explicitly used chickens as model to test the immune-protective efficacy of JlpA protein. Taking into account that gastrointestinal tract is the focal site for C. jejuni colonization, to extrapolate the benefit of mucosal (intragastric) delivery of JlpA protein, a food grade Nisin inducible Lactic acid producing bacteria, Lactococcus lactis (L. lactis) was engineered to express recombinant JlpA protein (rJlpA) in the surface of the bacteria. Following evaluation of optimal surface expression and functionality of recombinant JlpA protein expressed by recombinant L. lactis (rL. lactis), the immune-protective role of intragastric administration of live rL. lactis was assessed in commercial broiler chickens. In addition to the significant elevation of antigen specific mucosal immune responses in the intestine of chickens that received three doses of rL. lactis, marked upregulation of Toll-like receptor 2 (TLR2) gene expression in association with mixed pro-inflammatory responses (both Th1 and Th17 type) was observed. Furthermore, intragastric delivery of rJlpA expressed by rL. lactis, but not the injectable form, resulted in a significant reduction in C. jejuni colonization in chickens suggesting that mucosal delivery of live rL. lactis expressing JlpA serves as a promising vaccine platform to induce strong immune-protective responses against C. jejuni in chickens.

Keywords: chickens, lipoprotein adhesion of Campylobacter jejuni, immuno-protection, Lactococcus lactis, mucosal delivery

Procedia PDF Downloads 65