Journal ArticleDOI
The combined effect of high pressure and nisin on inactivation of microorganisms in milk.
TLDR
It was shown that the effect of HP on cells of a single species can vary; some HP-induced sublethal injury is irreversible, allowing the sensitisation of Gram-negative bacteria to nisin post HP treatment, and a combination of hurdles may allow lower pressures and shorter treatment times without compromising product safety.Abstract:
The behaviour of both Gram-negative and Gram-positive bacteria associated with milk, in response to application of high pressure (HP) combined with nisin, was evaluated. Escherichia coli, Pseudomonas fluorescens, Listeria innocua, and Lactobacillus viridescens grown separately in skim milk were pressure-treated at 250–500 MPa for 5 min at 20 °C in the presence of 0, 250, or 500 IU/ml nisin. Combining HP and nisin gave a greater inactivation of all four bacteria than when either was applied individually. A reduction of ≥ 8 log of L. viridescens and L. innocua in milk was achieved at 500 MPa for 5 min at 20 °C, in the presence of 500 IU/ml nisin. The Gram-negative bacteria were more sensitive to HP, either alone or in combination with nisin, than Gram-positive bacteria. Treatment at 400 MPa for 5 min with 500 IU/ml nisin, or at 250 MPa for 5 min with 500 IU/ml nisin, gave a > 8 log reduction of E. coli and P. fluorescens, respectively. By adding nisin to cell suspensions after HP treatment, it was shown that the effect of HP on cells of a single species can vary; some HP-induced sublethal injury is irreversible, allowing the sensitisation of Gram-negative bacteria to nisin post HP treatment. Reversible membrane damage in P. fluorescens caused by HP was demonstrated using fluorescent dye uptake before, after, or during HP treatment. Industrial relevance The synergistic microbial inactivation that can be achieved by HP treatment in the presence of nisin has applications not only for liquid milk but many other dairy and low-acid products. Such a combination of hurdles may allow lower pressures and shorter treatment times without compromising product safety.read more
Citations
More filters
Journal ArticleDOI
Bacteriocin-based Strategies for Food Biopreservation
TL;DR: The use of bacteriocins in the food industry can help to reduce the addition of chemical preservatives as well as the intensity of heat treatments, resulting in foods which are more naturally preserved and richer in organoleptic and nutritional properties.
Journal ArticleDOI
Opportunities and Challenges in High Pressure Processing of Foods
TL;DR: The key challenges identified include: heat transfer problems and resulting non-uniformity in processing, obtaining reliable and reproducible data for process validation, lack of detailed knowledge about the interaction between high pressure, and a number of food constituents, packaging and statutory issues.
Journal ArticleDOI
High‐pressure processing – effects on microbial food safety and food quality
TL;DR: The effects of high-pressure processing on microbial food safety and, to a lesser degree, food quality are discussed.
Journal ArticleDOI
Nisin as a Food Preservative: Part 1: Physicochemical Properties, Antimicrobial Activity, and Main Uses
TL;DR: The 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 are reviewed.
Journal ArticleDOI
Use of nisin and other bacteriocins for preservation of dairy products
TL;DR: In this article, the combination of bacteriocins with heat and non-thermal treatments, such as high pressure, pulsed electric fields and other antimicrobials, opens innovative possibilities for application in other dairy products in hurdle-type approach.
References
More filters
Journal ArticleDOI
Bacteriocins of gram-positive bacteria.
TL;DR: A group of antibacterial proteins produced by gram-positive bacteria have attracted great interest in their potential use as food preservatives and as antibacterial agents to combat certain infections due to gram- positive pathogenic bacteria.
Journal ArticleDOI
Applications of the Bacteriocin, Nisin
TL;DR: The established uses of nisin as a preservative in processed cheese, various pasteurised dairy products, and canned vegetables will be briefly reviewed, and its use as an adjunct in novel food processing technology such as higher pressure sterilisation and electroporation.
Journal ArticleDOI
Recent advances in the microbiology of high pressure processing
TL;DR: Ultrahigh Pressure offers interesting possibilities for food processing ranging from extraction of plant compounds, restructuring foods and rapid formation of small ice crystals as pressure leaves small molecules such as many flavour compounds and vitamins intact.
Journal ArticleDOI
High Pressure Processing
TL;DR: This section covers high pressure processing as an alternative technology for preservation of foods, which includes critical process factors, their effect on Inactivation levels and mechanisms of inactivation, as well as pathogens of concern and recommendations for surrogates.