جداسازی و شمارش باسیلوس سرئوس از شیرخام عرضه شده در شهر تبریز و جستجوی ژن ces در جدایه‌ها

نوع مقاله: علمی پژوهشی

نویسندگان

1 دانش آموخته کارشناسی ارشد، گروه میکروبیولوژی، موسسه آموزش عالی ربع رشید، تبریز، ایران

2 دانشیارگروه بهداشت مواد غذایی، واحد تبریز، دانشگاه آزاد اسلامی، تبریز، ایران.

چکیده

باسیلوس سرئوس یک باکتری گرم مثبت‌، اسپوردار است که انتشار وسیعی در طبیعت دارد و به عنوان یکی از عوامل عمده پاتوژن موادغذایی شناسایی شده است، اغلب در آلودگی غذاهای آماده و فراورده‌های شیر نقش ایفا می‌کند و باعث ایجاد دونوع مسمومیت غذایی: نوع اسهالی و نوع استفراغی می‌شود. هدف از این مطالعه، جداسازی و شمارش باسیلوس سرئوس در شیر خام عرضه شده در فروشگاه‌ها‌ی سطح شهر تبریز و جستجوی ژن ces در جدایه‌ها می‌باشد. برای این منظور، تعداد 120 نمونه شیر خام، طی اسفند ماه 1395 تا خرداد 1396 از فروشگاه‌ها‌ی شهر تبریز به صورت تصادفی ساده انتخاب و تحت شرایط استریل به آزمایشگاه بهداشت موادغذایی منتقل شد تا مورد جستجو، شناسایی و شمارش باسیلوس سرئوس به روش استاندارد ملی ایران و PCR قرار گیرند. طبق نتایج بدست آمده از روش کشت، از تعداد 120 نمونه شیرخام، (83/10 درصد) 13 نمونه آلوده به باکتری باسیلوس سرئوس بودند که میانگین بار آلودگی آن‌ها 8/2 بود. نتایجPCR  نشان داد که از 13 نمونه مثبت باسیلوس سرئوس 12 نمونه (3/92 درصد) دارای ژن استفراغ‌زای cesبودند. یافته‌های مطالعه حاضر نشان داد که شیرخام پتانسیل مسمومیت‌زایی به باسیلوس سرئوس را دارد و به کار گرفتن روش‌هایی جهت کاهش آلودگی به این باکتری در جریان فراوری فراورده‌های شیر الزامی می‌باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Isolation and enumeration of Bacillus cereus in raw milk distributed in Tabriz, Iran and detection of ces gene among the isolates

نویسندگان [English]

  • Mahdieh Heydarzadeh 1
  • afshin Javadi 2
1 M.Sc Student of Microbiology, Cellular and Molecular Biology Department, Institute of Rabe-Rashidieh, Tabriz, Iran.
2 Associate Professor of Department of Food Hygiene, Tabriz Branch, Islamic Azad University, Tabriz, Iran
چکیده [English]

Bacillus cereus is a gram-positive and spore-forming bacterium which is widely distributed in nature. It also has been known as a major food borne pathogen that often plays a role in the contamination of ready-to-eat and dairy products. It causes two different types of food poisoning in human: the diarrheal type and the emetic type. The aim of this study was to isolate and enumerate B. cereus in raw milk distributed in the stores of Tabriz city, Iran and to detect ces gene among the isolates. For this purpose, 120 samples of raw milk were randomly selected from the stores during February to June 2017. They were transferred to the Laboratory of food hygiene under sterile conditions in order to isolate, identify and enumerate B. cereus according to the national standard method of Iran and PCR. According to the results of microbial culture, out of 120 samples of raw milk, 13 (10.83%) samples were contaminated with B. cereus and the mean rate of contamination was 2.8 log10/ml. PCR results showed that of 13 positive samples, 12 (92.3%) samples contained ces gene which is responsible for vomiting. The results of this study showed that raw milk has the potential for human intoxication by B. cereus; and the use of procedures to reduce the bacterial contamination during the processing of dairy product is required.

کلیدواژه‌ها [English]

  • Bacillus cereus
  • raw milk
  • ces gene
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