J Appl Microbiol
Laboratory of Epidemiology and Veterinary Microbiology, Bacteriology and Biotechnology Development Groups, Pasteur Institute of Tunisia (IPT), University Manar, Tunis, Tunisia.
Published: July 2013
Aims: To investigate the combined effect of hydrostatic pressure (HP), moderate temperature and nisin on the inactivation of Bacillus sporothermodurans spores which are known to be contaminant of dairy products and to be extremely heat-resistant.
Methods And Results: A central composite experimental design with three factors, using response surface methodology, was used. By analysing the response surfaces and their corresponding contour plots, an interesting interaction with the three factors was observed. The inactivation observed was shown to be well fitted with values predicted by the quadratic equation, since the adjusted determination coefficient (R(adj)(2)) was 0·979. The optimum process parameters for a 5-log spores ml(-1) reduction of B. sporothermodurans spores were obtained, 472 MPa/53°C for 5 min in presence of 121 UI ml(-1) of nisin.
Conclusion: Nisin and temperature treatments improve the effectiveness of pressure in the inactivation of highly heat-resistant spores of B. sporothermodurans.
Significance And Impact Of The Study: This study shows the potential of using high HP for a short time (5 min) in combination with moderate temperature and nisin to inactivate B. sporothermodurans spores in milk. Such treatments could be applied by the dairy industry to ensure the commercial sterility of UHT milk.
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http://dx.doi.org/10.1111/jam.12220 | DOI Listing |
Braz J Microbiol
September 2023
InovaLeite - Laboratório de Pesquisa em Leites e Derivados, Departamento de Tecnologia de Alimentos, Universidade Federal de Viçosa, Viçosa, MG, 36570 900, Brazil.
Among the milk contaminating microorganisms, those which are able to form heat-resistant spores are concerning, especially for dairy companies that use ultra-high temperature (UHT) technology. These spores, throughout storage, can germinate and produce hydrolytic enzymes that compromise the quality of the final product. This study evaluated 184 UHT milk samples from different batches collected from seven Brazilian dairy companies with a possible microbial contamination problem.
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November 2021
Midwest Dairy Foods Research Center, Dairy and Food Science Department, South Dakota State University, Brookings 57007.
The presence of spore-forming microorganisms and their adhesion to contact surfaces in dairy plants is a major concern because dairy products are prone to cross-contamination. Spore formers and their spores can survive milk processing treatments due to their heat resistance. One source of these spore formers is bacterial biofilms, which grow and accumulate on most surfaces in dairy industrial plants, such as pipes, heat exchangers, pasteurized plates, and storage tanks.
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September 2021
Department of Food Science and Nutrition, School of Food Engineering, State University of Campinas, Campinas, SP, Brazil.
The presence of mesophilic and thermophilic spore-forming bacteria in UHT milk, as well as biofilm formation in dairy plants, are concerning. The current study explored the spore-forming bacilli diversity in 100 samples of UHT milk (skimmed and whole). Through this work, a total of 239 isolates from UHT milk samples were obtained.
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October 2021
Faculty of Pharmaceutical Sciences, Nagasaki International University.
We previously identified a new Bacillus sporothermodurans strain, TM-I-3, which produces volatile compounds that show potent inhibitory activity against certain types of fungi, including Aspergillus fumigatus and Cladosporium cladosporioides. Non-contact antifungals derived from this bacterium may provide multidirectional inhibition and may be useful in disease prevention. This study is aimed at identifying the stage of fungal growth that is inhibited by TM-I-3 to elucidate the mechanism of its contact-independent antifungal activity.
View Article and Find Full Text PDFMicroorganisms
January 2021
Department of Microbiology and Biotechnology, Max Rubner-Institut (MRI), Federal Research Institute of Nutrition and Food, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany.
The genetic heterogeneity of (formerly was evaluated using whole genome sequencing. The genomes of 29 previously identified and two strains isolated from ultra-high-temperature (UHT)-treated milk were sequenced by short-read (Illumina) sequencing. After sequence analysis, the two strains could be reclassified as .
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