Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Record number 507050
Title Determination of single cell lag times of Cronobacter spp. strains exposed to different stress conditions : Impact on detection
Author(s) Margot, H.; Zwietering, M.H.; Joosten, H.; Stephan, R.
Source International Journal of Food Microbiology 236 (2016). - ISSN 0168-1605 - p. 161 - 166.
DOI http://dx.doi.org/10.1016/j.ijfoodmicro.2016.08.002
Department(s) Food Microbiology Laboratory
VLAG
Publication type Refereed Article in a scientific journal
Publication year 2016
Keyword(s) Bacterial inactivation - Enrichment - Powdered infant formula - Sampling plan - Simulation - Strain variability
Abstract

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.

Comments
There are no comments yet. You can post the first one!
Post a comment
 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.