{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T13:57:27Z","timestamp":1768831047633,"version":"3.49.0"},"reference-count":20,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,9,10]],"date-time":"2021-09-10T00:00:00Z","timestamp":1631232000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100008465","name":"Forschungskreis der Ern\u00e4hrungsindustrie","doi-asserted-by":"publisher","award":["AiF 19358 N"],"award-info":[{"award-number":["AiF 19358 N"]}],"id":[{"id":"10.13039\/501100008465","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["MPs"],"abstract":"<jats:p>In the food and pharmaceutical industries, evaluating the sterilization performance preceding aseptic production processes is of central importance. In the case of hydrogen peroxide sterilization of solid surfaces, bioindicators (BI) consisting of spores of Bacillus atrophaeus or Geobacillus stearothermophilus are used to validate the effectiveness and efficiency of the inactivation procedure. Commercial production of G. stearothermophilus is commonly performed on agar plates, where cultivation and sporulation conditions are not well-defined. Therefore, the produced BI can vary in their resistance, which in turn creates unacceptable uncertainties in the evaluation of aseptic processes. Submerged production in the bioreactor would allow more control over sporulation conditions, while reducing production time, resistance variability, and avoidance of false-positive or false-negative test results. In addition, submerged production of G. stearothermophilus so far was a challenge to achieve sufficiently high spore concentrations for BI production. This study reports on the development of a method for submerged production of G. stearothermophilus spores (pH 7.0, 57 \u00b0C, 30% pO2) that can achieve 1.6 \u00d7 107 spores\/mL with a resistance against 35% H2O2 at 25 \u00b0C of D25\u00b0C,35% H2O2 = 73 s. This resistance ranks within the range of commercially available BI, making the results directly transferable to industrial applications.<\/jats:p>","DOI":"10.3390\/mps4030063","type":"journal-article","created":{"date-parts":[[2021,9,12]],"date-time":"2021-09-12T21:48:01Z","timestamp":1631483281000},"page":"63","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Submerged Bioreactor Production of Geobacillus stearothermophilus ATCC 7953 Spores for Use as Bioindicators to Validate Hydrogen Peroxide Inactivation Processes"],"prefix":"10.3390","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6209-1724","authenticated-orcid":false,"given":"Philipp","family":"Stier","sequence":"first","affiliation":[{"name":"TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9598-9242","authenticated-orcid":false,"given":"Ulrich","family":"Kulozik","sequence":"additional","affiliation":[{"name":"TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,10]]},"reference":[{"key":"ref_1","unstructured":"FDA (2007). 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Molecules, 25.","DOI":"10.3390\/molecules25132985"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"562","DOI":"10.1128\/AEM.02520-14","article-title":"Modeling the Recovery of Heat-Treated Bacillus licheniformis Ad978 and Bacillus weihenstephanensis KBAB4 Spores at Suboptimal Temperature and pH Using Growth Limits","volume":"81","author":"Trunet","year":"2014","journal-title":"Appl. Environ. 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