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Processing and Properties of Poly(lactic acid)/Nanocellulose Nanocomposites
Published in R. Jumaidin, S.M. Sapuan, H. Ismail, Biofiller-Reinforced Biodegradable Polymer Composites, 2020
R.Z. Khoo, W.S. Chow, H. Ismail
Salmieri et al. [51] prepared bioactive PLA/CNC films containing nisin to investigate their antimicrobial properties on cooked ham. Nisin is a type of bacteriocin, which is commonly used in bioactive food packaging. It is a small polypeptide (34 amino acids) produced from Gram-positive bacterium Lactococcus lactis subsp. lactis. Nisin is effective against a wide variety of foodborne pathogens such as Listeria monocytogenes, S. aureus, Clostridium botulinum, and its spore. PLA/CNC films were first compression-molded and placed in an aqueous solution of nisin for 24 h. The presence of CNC is critical as it is capable to enhance the nisin binding onto PLA/CNC chains via hydrogen bonding. L. monocytogenes was used in this study as this pathogen is commonly found on raw meat and cooked ham offers appropriate conditions for pathogen growth. PLA films that contain nisin showed a significant reduction of L. monocytogenes in ham from day 1 and a total inhibition from day 3. Besides, the percentage of nisin release also increased continuously from day 0 to day 14 (21% at day 14). These results confirm the antimicrobial effectiveness of PLA/CNC/nisin films in pathogen inhibition of meat products.
Encapsulation of Flavors, Nutraceuticals, and Antibacterials
Published in Munmaya K. Mishra, Applications of Encapsulation and Controlled Release, 2019
Stéphane Desobry, Frédéric Debeaufort
Nisin has been increasingly used as a biopreservative for direct incorporation in food as well as in active/edible films. Nisin effectively inhibits Gram-positive bacteria and outgrowth spores of Bacillus and Clostridium. If nisin is efficient against particular microorganisms, its activity rapidly decreases as it is hydrolyzed in the food product, and bacterial inactivation stops. All studies showed a restarting of bacterial growth a few days after nisin incorporation. Encapsulation and controlled release is an efficient way to avoid this resumption of bacterial growth, because active nisin is slowly delivered into the food or onto the food surface. In a recent study on edible films (Sebti et al., 2007) using HPMC/chitosan and incorporating pure nisin, the author evaluated the effect of nisin on the physical characteristics of films.
Use of Nanotechnology as an Antimicrobial Tool in the Food Sector
Published in Alok Dhawan, Sanjay Singh, Ashutosh Kumar, Rishi Shanker, Nanobiotechnology, 2018
María Ruiz-Rico, Édgar Pérez-Esteve, José M. Barat
There are numerous references to the encapsulation of antimicrobial proteins (bacteriocins) and enzymes in liposomes, such as pediocin (Degnan and Luchansky 1992), nisin (Benech et al. 2002, Colas et al. 2007, Taylor et al. 2008), or lysozyme (Were et al. 2004). Some of these encapsulated compounds have been included and tested in food systems. Nisin is an antimicrobial peptide produced by strains of Lactococus lactis, and has been recognized as being safe for food applications by the Joint Food and Agriculture Organization/World Health Organization (FAO/WHO) Expert Committee on Food Additives (da Silva Malheiros et al. 2010). Using nisin in its free form is expensive and is associated with loss of activity due to the degradation or deactivation, and emergence, of nisin-resistant microbial strains. Benech et al. (2002) added encapsulated and free nisin to cheese-milk solution and observed that Listeria innocua diminished during the ripening process of cheese. Laridi et al. (2003) incorporated nisin-loaded liposomes during the fermentation process of cheddar cheese with long-term stability of vesicles during storage time. More recently, da Silva Malheiros et al. (2010) tested the antimicrobial activity of nisin-loaded liposomes in combination with refrigeration in milk inoculated with L. monocytogenes. The inhibitory rate for liposomes and free nisin was similar, but encapsulation seemed important to help overcome stability issues and interaction with food components during long-term storage.
Production of nisin from Lactococcus lactis in acid-whey with nutrient supplementation
Published in Preparative Biochemistry & Biotechnology, 2023
Sahana Vijayakumar, Vishnu G., Prajna Rao Krishnapura, Regupathi Iyyaswami
A bacteriocin, Nisin, produced by lactic acid bacteria (LAB) has garnered a lot of attention as a natural preservative in the food industry because of its proven safety and potency against various food spoilage microbes and pathogenic bacteria.[7] Nisin is a small amphiphilic peptide of about 3000 Da produced by the Lactococcus lactis species with antagonistic activity against many gram-positive bacteria.[8] Nisin belongs to the ‘Type A’ lantibiotics, whose primary mode of inactivation is forming pores in the cytoplasmic membrane of the microorganisms. The presence of unusual amino acids in nisin, such as lanthionines, provides thermostability, acid tolerance, resistance to proteolytic degradation, and antibiotic activity. Therefore, nisin can be used as a preservative even with foods processed at higher temperatures or food systems with natural proteases.[7] Nisin is effective in small concentrations. It is also toxicologically safe and not known to cause any side effects or adverse interactions like antibiotics.[9] Hence, it is considered “Generally Regarded as Safe (GRAS)” by US Food and Drug Administration,[10] and listed as an approved food additive in the EU.[11] The most prominent antimicrobial peptide, nisin, is currently used as a food preservative in dairy, beverage, meat, and vegetable products.[12]
Human and livestock pathogens and their control during composting
Published in Critical Reviews in Environmental Science and Technology, 2022
Enzymes produced by native microorganisms, such as alkaline proteases, are particularly important for several reasons. They are stable and active at high pH and in the presence of surfactants and oxidizing agents. They are produced by bacteria, molds, and yeasts. Most of them are isolated from Bacillus species and fungal species found in composts such as Aspergillus species (Hajji et al., 2007). Most of these enzymes have an optimum pH of 8.0–9.5 and are active between 40 °C and 70 °C (Tremacoldi et al., 2007). Lactococcus lactis subsp. lactis, another thermophilic bacterium, can produce a small peptide called nisin. Nisin has antimicrobial properties against gram-positive bacteria such as Bacillus cereus, Clostridium botulinum, Clostridium sporogenes, Enterococcus spp., Listeria monocytogenes, and Staphylococcus spp. (Cetin-Karaca, 2011). Nisin is stable in thermophilic conditions and has sporostatic properties. meaning that it is capable of inhibiting spore germination. In vegetative cells, nisin forms pores in the cytoplasmic membrane, destroying the cell membrane integrity resulting in leakage of cytoplasmic content (Raybaudi-Massilia et al., 2009).