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| Contact |
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Beyrer Michael |
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| Title |
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Microbial decontamination of porous model food powders by Vacuum-Steam-Vacuum treatment |
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| Author(s) |
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Josef T. Hörmansperger, Leandro Buchmann, Samuel Merz, Rudolf Schmitt, Michael Beyrer, Erich J.Windhab |
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| References |
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Innovative Food Science and Emerging Technologies 34 (2016) 367–375 |
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| Url |
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http://dx.doi.org/10.1016/j.ifset.2015.12.027 |
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| Abstract |
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The objective of this work was to study the systematic inactivation of immobilized heat-resistant, validated wild-type bacteria (sporulated Bacillus subtilis D2 and vegetative Cronobacter sakazakii H30) in porous enlarged model food powder particles using the Vacuum-Steam-Vacuum (VSV) process. Developed bacterial sensors allowed a
local contamination of model particles at a defined intraparticle position. Contradicting previous studies, a spore inactivation of 4 log 10 CFU in high depths of up to 10 mm (particle core) was possible by VSV treatment despite a noticeable intraparticle attenuation. To mimic inactivation in smaller food powder particles, similar-sized bacterial sensors were treated and showed slightly curve-linear kinetics explained by a short warm-up phase (lag time). Measured inactivation was lower than that predicted by traditional capillary (z = 8.0 ∘C)
treatment of suspensions due to non-linearity in the high temperature regime. This could be described by twice as high z values of 15.4 °C (no lag time) and 17.2 °C (lag time), respectively. Industrial relevance of present work: The emerging Vacuum-Steam-Vacuum(VSV) decontamination process aims at efficient heat transfer on solid surfaces and pores using saturated steam as the heat-transferring fluid. VSV was already used for treating vegetables, fruits, meats and spices. This work describes use of VSV for dry porous solids. |
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