Determination of single cell lag times of Cronobacter spp. strains exposed to different stress conditions: Impact on detection
| Autor: | Marcel H. Zwietering, Han Joosten, Roger Stephan, H. Margot |
|---|---|
| Přispěvatelé: | University of Zurich, Stephan, Roger |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Hot Temperature Lag 030106 microbiology Cell Colony Count Microbial 610 Medicine & health Microbiology Levensmiddelenmicrobiologie Stress (mechanics) 03 medical and health sciences Strain variability Stress Physiological Sampling plan medicine Humans Food science Desiccation Cronobacter 10082 Institute of Food Safety and Hygiene 1106 Food Science VLAG biology 2404 Microbiology General Medicine Contamination Stress resistance biology.organism_classification Kinetics 030104 developmental biology medicine.anatomical_structure Enrichment Powdered infant formula Food Microbiology 570 Life sciences Bacterial inactivation Stress conditions Simulation Food Science |
| Zdroj: | International Journal of Food Microbiology, 236, 161-166 International Journal of Food Microbiology 236 (2016) |
| ISSN: | 0168-1605 |
| Popis: | The variability of stress resistance and lag time of single cells can have a big impact on their growth and therefore on the probability of their detection in food. In this study, six strains of Cronobacter spp. were subjected to heat, acid and desiccation stress and single cell lag times were determined using optical density measurements. The duration of lag time was highest after acid stress and did not correlate to stress resistance. The effect that the inactivation caused by stress and an extended lag time had on the projected cfu level reached after enrichment was simulated in different scenarios. For most strains, an enrichment time of 18 h was sufficient for stressed cells to reach the suggested minimum level of cell inoculum for the Cronobacter screening broth detection. Particular strains may require longer recovery periods. Further, probability calculations showed that the number of samples taken from a batch may have an important effect on detection probability, especially at low contamination rates. Therefore, in addition to increasing the recovery period, increasing the number of samples is a suitable strategy to improve detection. |
| Databáze: | OpenAIRE |
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