Bebek ve çocuk beslenmesinde kullanılan gıdalarda bacillus cereus varlığı ile izolatların toksijenik özelliğinin belirlenmesi

EDİP URHAN

Bebek ve çocuk beslenmesinde kullanılan gıdalarda bacillus cereus varlığı ile izolatların toksijenik özelliğinin belirlenmesi

Thesis Type: Postgraduate

Institution Of The Thesis: Hatay Mustafa Kemal University, SAĞLIK BİLİMLERİ ENSTİTÜSÜ, VETERİNERLİK GIDA HİJYENİ VE TEKNOLOJİSİ ANABİLİM DALI, Turkey

Approval Date: 2022

Thesis Language: Turkish

Student: EDİP URHAN

Supervisor: Hayriye Yeşim Can

Open Archive Collection: AVESIS Open Access Collection

Abstract:

In this study, 30 domestic and imported dried baby formulas, 25 canned baby formulas, and 25 cereal based products (flour, starch, rice flour and semolina sold in packed or unpacked form) belonging to different companies were used as materials. A total of 80 samples were examined for the presence of Bacillus cereus by classical culture technique and PCR method. The obtained isolates were confirmed as B. cereus by targeting the hemolysin gene. The presence of toxin genes (nhe, hbl, cytK, ces) was investigated by multiplex PCR method. As a result of the study, B. cereus was isolated from 50 (62.5 %) of the total 80 samples analyzed. B. cereus was not found in canned baby formula samples. Dried baby formulas and cereal based products were found to be contaminated with B. cereus at a level of 83.3 %, 100 %, respectively. A total of 50 isolates obtained from positive samples were confirmed by PCR by targeting the hemolysin gene. Enterotoxin genes were found in a total of 13 isolates, and 26 % of the isolates were found to be enterotoxigenic. The nhe gene was only found in three isolates, and both nhe and cytK genes were found in 10 isolates. It was observed that none of the isolates carried the ces gene encoding the toxin responsible for emetic syndrome and the hbl gene encoding the toxin responsible for diarrheal syndrome. All of the isolates were phenotypically found to be capable of hemolysis on blood agar. It was determined that two isolates were psychrotrophic and can grow at 7 oC. These results indicate that the foods used for infant and young child nutrition may carry a risk for the presence of toxigenic and psychrotrophic B. cereus strains.