Bebek ve çocuk beslenmesinde kullanılan gıdalarda bacıllus cereus varlığı ile izolatların toksijenik özelliğinin belirlenmesi
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Dosyalar
Tarih
2022
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Hatay Mustafa Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu tez çalışmasında, farklı firmalara ait 30 adet yerli ve ithal olarak üretilen toz formunda bebek maması, 25 adet cam kavanozda konserve formundaki mama ile 25 adet bebek beslenmesinde kullanılan tahıl bazlı ürünler (açık veya kapalı formda satılan un, nişasta, pirinç unu ve irmik) materyal olarak kullanıldı. Toplam 80 adet örnek, Bacillus cereus varlığı yönünden klasik kültür tekniği ve PCR yöntemi ile incelendi. Elde edilen izolatlar hemolizin geni hedef alınarak B. cereus olarak doğrulandı. Doğrulanan izolatlarda toksin genlerinin (nhe, hbl, cytK, ces) varlığı multipleks PCR yöntemiyle araştırıldı. Çalışmanın sonucunda, analize alınan toplam 80 örneğin 50'sinden (% 62.5) B. cereus izole edildi. Cam kavanozda konserve tipindeki mama örneklerinde B. cereus'a rastlanılmadı. Toz formundaki bebek mamaları ile tahıl bazlı ürünler sırasıyla % 83.3, % 100 düzeylerinde B. cereus ile kontamine olarak bulundu. Pozitif örneklerden elde edilen, toplam 50 adet izolat hemolizin geni hedef alınarak PCR ile doğrulandı. Toplam 13 izolatta enterotoksin genine rastlanılarak, izolatların % 26'sının enterotoksijenik özellikte olduğu bulundu. Üç izolatta sadece nhe genine, 10 izolatta hem nhe hem de cytK genlerine birlikte rastlanıldı. Emetik sendromdan sorumlu toksini kodlayan ces ile diyarel sendromdan sorumlu toksini kodlayan hbl genlerini hiçbir izolatın taşımadığı gözlendi. Fenotipik olarak, tüm izolatların kanlı agarda hemoliz oluşturabildiği bulundu. İki izolatın psikrotrofik özellikte olduğu ve 7 oC'de üreyebildiği saptandı. Bu sonuçlar, bebek ve küçük çocuk beslenmesinde kullanılan gıdaların, toksijenik ve psikrotrofik özellikteki B. cereus suşlarının varlığı açısından risk taşıyabileceğini göstermektedir
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.
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.
Açıklama
Anahtar Kelimeler
Besin Hijyeni ve Teknolojisi, Food Hygiene and Technology
