133827

Physiological and Molecular Studies on Thermotolerance of Bacillus cereus Isolated from Some Dairy Products and Fast Foods

Article

Last updated: 03 Jan 2025

Subjects

-

Tags

Academic and Pre-clinical Veterinary Sciences (Physiology, Histology, …rology, Parasitology, Pharmacology, Forensic Medicine and Toxicology)

Abstract

Several members of Bacillus cereus (B. cereus) have been recognized as a significant agent of food and health problems. Thermotoleranc of B. cereus after pre-exposure to temperature shifts or other stress may influence its ability to grow in minimally processed foods. This study was proposed to determine the recovery rate of B. cereus group from dairy products and fast foods. Moreover, the responses of a recovered isolate to different stresses were evaluated to stand upon its thermotolerance against lethal temperature. In total, 200 different samples from milk and milk products (164) and fast food (36) were examined for the presence of B. cereus group. The effects of heat, cold, acid and salt stresses on heat resistant B. cereus were physiologically and molecularly assessed through examining its viability and measuring the gene expression of its heat induced proteins (GroEL and DnaJ) by reverse transcription quantitative polymerase chain reaction (RT-qPCR), respectively. Overall, 35 (17.5%) samples were positive for B. cereus group isolates. The higher B. cereus count (> 104 CFU/mL or g) was found in 7% of milk and fast food samples. Three B. cereus group species (B. cereus, B. thuringiensis and B. pseudomycoides or B. mycoides) were identified. After time intervals of mild heat pre-exposure at 42 °C or exposure to other stresses, B. cereus developed an increased thermotolerance at 50 °C/20 min. This thermotolerance was pronounced after exposure of B. cereus cells to 42°C /1 h and 2.5 % salt / 30°C/ 40 min with a 3.9 CFU log increase compared to those exposed to lethal treatment only. Molecularly, RT-qPCR results revealed up-regulation of dnaJ gene expression in pretreated cells compared to the lethal treated cells only. Overall, these results confirmed the heat resistance occurs in B. cereus during food processing, which results in its survival in the food products.

DOI

10.21608/zvjz.2020.35504.1113

Keywords

B. cereus, viability, Thermotolerance, dnaJ gene, B. cereus RT-qPCR

Authors

First Name

Aham

Last Name

Gharib

MiddleName

-

Affiliation

Microbiology Department, Faculty of Veterinary Medicine, Zagazig University, 44511, Zagazig, Sharkia Governorate, Egypt

Email

ahlamabdelazizgharib@yahoo.com

City

zagazig

Orcid

-

First Name

Marwa

Last Name

Abd El-Hamid

MiddleName

-

Affiliation

Microbiology Department, Faculty of Veterinary Medicine, Zagazig University, 44511, Zagazig, Sharkia Governorate, Egypt

Email

mero_micro2006@yahoo.com

City

Zagazig

Orcid

-

First Name

Engy

Last Name

Ayob

MiddleName

-

Affiliation

Microbiology Department, Faculty of Veterinary Medicine, Zagazig University, 44511, Zagazig, Sharkia Governorate, Egypt

Email

drengyyonan@gmail.com

City

zagazig

Orcid

-

Volume

48

Article Issue

4

Related Issue

19974

Issue Date

2020-12-01

Receive Date

2020-08-04

Publish Date

2020-12-01

Page Start

354

Page End

365

Print ISSN

1110-1458

Online ISSN

2357-075X

Link

https://zvjz.journals.ekb.eg/article_133827.html

Detail API

https://zvjz.journals.ekb.eg/service?article_code=133827

Order

2

Type

Original Article

Type Code

601

Publication Type

Journal

Publication Title

Zagazig Veterinary Journal

Publication Link

https://zvjz.journals.ekb.eg/

MainTitle

Physiological and Molecular Studies on Thermotolerance of Bacillus cereus Isolated from Some Dairy Products and Fast Foods

Details

Type

Article

Created At

22 Jan 2023