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Your search keyword '"BIESTA-PETERS, ELISABETH G."' showing total 13 results
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13 results on '"BIESTA-PETERS, ELISABETH G."'

7. Quantification of the emetic toxin cereulide in food products by liquid chromatography-mass spectrometry using synthetic cereulide as a standard

Author

Biesta-Peters, Elisabeth G., Reij, Martine W., Rajkovic, Andreja, Ehling-Schulz, Monika, Abee, Tjakko, Blaauw, Richard H., and inEt Veld, Paul H.;

Subjects
Liquid chromatography -- Analysis, Emetics -- Analysis, Biological sciences
Abstract

The biological activity of synthetic cereulide is tested and its use as a standard in the quantification of cereulide contents in food samples is validated. The recovery experiments using cereulide-spiked food products and acetonitrile as extraction solute has shown that the liquid chromatography-mass spectrometry (LC-MS) method with cereulide as a standard is a reliable and accurate method for quantifying cereulide in food, as the recovery rate is close to 100% over a wide concentration range.

Published
2010

8. Comparing nonsynergistic gamma models with interaction models to predict growth of emetic Bacillus cereus when using combinations of pH and individual undissociated acids as growth-limiting factors

Author

Biesta-Peters, Elisabeth G., Reij, Martine W., Gorris, Leon G., and Zwietering, Marcel H.

Subjects
Bacillus cereus -- Genetic aspects, Bacillus cereus -- Physiological aspects, Hydrogen-ion concentration -- Analysis, Biological sciences
Abstract

The quantification of hurdle technology has identified synergistic or multiplicative effects and the validity of the gamma hypothesis is tested with respect to the use of pH and various concentrations of undissociated acids to control growth of Bacillus cereus in brain heart infusion broth. The studies have shown that the introduction of synergy factors into the models have not improved the quality of the prediction, but have led to the overestimation of the growth boundary.

Published
2010

12. Characterization and Exposure Assessment of Emetic Bacillus cereusand Cereulide Production in Food Products on the Dutch Market

Author

Biesta-Peters, Elisabeth G., Dissel, Serge, Reij, Martine W., Zwietering, Marcel H., and in 't Veld, Paul H.

Abstract

The emetic toxin cereulide, which can be produced by Bacillus cereus, can be the cause of food poisoning upon ingestion by the consumer. The toxin causes vomiting and is mainly produced in farinaceous food products. This article includes the prevalence of B. cereusand of cereulide in food products in The Netherlands, a characterization of B. cereusisolates obtained, cereulide production conditions, and a comparison of consumer exposure estimates with those of a previous exposure assessment. Food samples (n= 1,489) were tested for the presence of B. cereus; 5.4% of the samples contained detectable levels (>102CFU/g), and 0.7% contained levels above 105CFU/g. Samples (n= 3,008) also were tested for the presence of cereulide. Two samples (0.067%) contained detectable levels of cereulide at 3.2 and 5.4 μg/kg of food product. Of the 481 tested isolates, 81 produced cereulide and/or contained the cesgene. None of the starch-positive and hbl-containing isolates possessed the cesgene, whereas all strains contained the nhegenes. Culture of emetic B. cereusunder nonoptimal conditions revealed a delay in onset of cereulide production compared with culture under optimal conditions, and cereulide was produced in all cases when B. cereuscells had been in the stationary phase for some time. The prevalence of cereulide-contaminated food approached the prevalence of contaminated products estimated in an exposure assessment. The main food safety focus associated with this pathogen should be to prevent germination and growth of any B. cereuspresent in food products and thus prevent cereulide production in foods.

Published
2016
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13. Quantification of the Emetic Toxin Cereulide in Food Products byLiquid Chromatography-Mass Spectrometry Using Synthetic Cereulide as a Standard.

Author

Biesta-Peters, Elisabeth G., Reij, Martine W., Blaauw, Richard H., Veld, Paul H. in 't, Rajkovic, Andreja, Ehling-Schulz, Monika, and Abee, Tjakko

Subjects
*LIQUID chromatography, *MASS spectrometry, *BACILLUS cereus, *EUKARYOTIC cells, *ACETONITRILE
Abstract

Bacillus cereus produces the emetic toxin cereulide, a cyclic dodecadepsipeptide that can act as a K+ ionophore, dissipating the transmembrane potential in mitochondria of eukaryotic cells. Because pure cereulide has not been commercially available, cereulide content in food samples has been expressed in valinomycin equivalents, a highly similar cyclic potassium ionophore that is commercially available. This research tested the biological activity of synthetic cereulide and validated its use as a standard in the quantification of cereulide contents in food samples. The synthesis route consists of 10 steps that result in a high yield of synthetic cereulide that showed biological activity in the HEp-2 cell assay and the boar sperm motility assay. The activity is different in both methods, which may be attributed to differences in K+ content of the test media used. Using cereulide or valinomycin as a standard to quantify cereulide based on liquid chromatography-mass spectrometry (LC-MS), the concentration determined with cereulide as a standard was on average 89.9% of the concentration determined using valinomycin as a standard. The recovery experiments using cereulide-spiked food products and acetonitrile as extraction solute showed that the LC-MS method with cereulide as a standard is a reliable and accurate method to quantify cereulide in food, because the recovery rate was close to 100% over a wide concentration range. [ABSTRACT FROM AUTHOR]

Published
2010
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