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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Survival variability of 12 strains of Bacillus cereus yielded to spray drying of whole milk

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Author(s):
Alvarenga, Veronica O. [1] ; Brancini, Guilherme T. P. [2] ; Silva, Eric K. [3] ; da Pia, Arthur K. R. [1] ; Campagnollo, Fernanda B. [1] ; Braga, Gilberto U. L. [2] ; Hubinger, Miriam D. [3] ; Sant'Ana, Anderson S. [1]
Total Authors: 8
Affiliation:
[1] Univ Estadual Campinas, Dept Food Sci, Fac Food Engn, Campinas, SP - Brazil
[2] Univ Sao Paulo, Fac Phannaceut Sci, Dept Clin Toxicol & Bromatol Anal, Ribeirao Preto, SP - Brazil
[3] Univ Estadual Campinas, Fac Food Engn, Dept Food Engn, Campinas, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: International Journal of Food Microbiology; v. 286, p. 80-89, DEC 2 2018.
Web of Science Citations: 4
Abstract

The variability in spore survival during spray drying of 12 Bacillus cereus strains was evaluated. B. cereus spores were inoculated on whole milk (7.2 +/- 0.2 log(10) spores/g dry weight) and processed in a spray-dryer. Twelve independent experiments were carried out in triplicate. The spore count was determined before and after each drying process, based on the dry weight of whole milk and powdered milk. Then, the number of decimal reductions (gamma) caused by the spray drying process was calculated. B. cereus strains presented gamma values ranging from 1.0 to 4.7 log10 spores/g dry weight, with a high coefficient of variation (CV) of 46.1%. Cluster analysis allowed to group B. cereus as sensitive (strains 511, 512, 540, 432 and ATCC 14579), intermediate (strains B18, B63, and B86) and resistant strains (strains B3, B94, B51 and 436). Three strains (one of each group) were selected for further investigation and characterization of their physicochemical and molecular (proteomics) differences. Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were used to determine physicochemical characteristics and glass transition temperature (T-g), respectively. No differences in signs among the three strains were found in spectra ranging from 900 to 4000 cm(-1). The endothermic peak ranged between 54 and 130 degrees C for strain 540; between 81 and 163 degrees C for strain B63; and between 110 and 171 degrees C for strain 436. However, they showed different T-g: 88.82 degrees C for strain 540; 114.32 degrees C for strain B63; and 122.70 degrees C for strain 436. A total of eleven spots were identified by mass spectrometry, with the spore coat protein GerQ, sporulation protein YtfJ (GerW), and peptidyl-prolyl cis-trans isomerase being found in at least two strains. Altogether, the results suggested that the high survival variability of B. cereus spores to the spray drying process seems to be mainly associated with different T-g and protein content. The study highlights the importance of quantifying the effects of this unit operation over the target microorganisms. These data may be relevant for the development of effective measures aiming to control the occurrence of B. cereus in milk powder as well as to reduce spoilage or safety issues associated with the presence of this bacterium in foods, particularly those formulated with milk powder. (AU)

FAPESP's process: 15/24305-0 - Evaluating the effects of blue and red light on the stress tolerance and the proteome of the entomopathogenic fungus Metarhizium acridum
Grantee:Guilherme Thomaz Pereira Brancini
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 16/11386-5 - Mechanistic study of perception and response to visible light in the entomopathogenic fungus Metarhizium acridum
Grantee:Gilberto Úbida Leite Braga
Support type: Regular Research Grants
FAPESP's process: 14/14891-7 - Modelling the inhibition of Listeria monocytogenes by lactic acid bacteria (LAB) in traditional Minas cheeses
Grantee:Fernanda Bovo Campagnollo
Support type: Scholarships in Brazil - Post-Doctorate