Toxin production ability of Bacillus cereus strains from food product of Ukraine

Abstract

Abstract. Potential pathogens of foodborne toxic infections -bacterial contaminants Bacillus cereus isolated from plant raw materials and food products from the Ukrainian region were investigated. When determining of the proportion of isolated bacilli from the plant samples, it was established that the epidemiologically significant microorganisms of Bacillus cereus as agents of food poisoning are the second largest. The average value of contaminated samples of Ukrainian plant raw materials and processed products with Bacillus cereus is 36.2 %. The ability of Bacillus cereus strains identified by a complex of morphological, tinctorial, cultural and biochemical properties, to produce specific emetic and enterotoxins was studied. Molecular genetic diagnosis and detection of the toxin-producing ability of isolated 42 Bacillus cereus strains showed both the possibility of their rapid identification and the presence of specific toxicity genes. Multiplex polymerase chain reaction (PCR) was carried out with specific primers to detect toxicity determined of various bacilli genes: nheA, hblD, cytK, cesВ. The distribution of toxigenic genes is significantly different among the Bacillus cereus isolates from various sources. The nheA, hblD and cytK enterotoxin genes were detected in 100, 83.3 and 61.9 % of the investigated strains of Bacillus cereus, respectively. The cesB gene encoding emetic toxin was detected in 4.8 % of strains. Molecular-genetic PCR-method confirmed that all the isolated strains belong to the Bacillus cereus group, and the ability to produce toxins can be attributed to five groups. The main toxins that produce the investigated Bacillus cereus strains were nhe and hbl enterotoxins encoded by the corresponding genes of nheA and hblD. The enterotoxic type of Bacillus cereus was predominant in Ukrainian region. Studies of domestic plant food raw materials and products have confirmed the need to improve microbiological control of product safety by introducing accelerated specific diagnostics of contaminants by molecular genetics methods.Key words: toxin-producing Bacillus cereus, enterotoxins, emetic toxin, molecular genetic diagnosis, polymerase chain reaction, food safety. Анотація. Досліджено потенційні збудники харчових токсикоінфекцій -токсигенні бацилярні контамінанти Bacillus cereus, виділені з рослинної сировини і продукції харчової промисловості українського регіону. Середнє зна-чення контамінованості Bacillus cereus зразків української рослинної сировини і продуктів її переробки становить 36,2 %. Вивчено здатність штамів Bacillus cereus, ідентифікованих за комплексом морфологічних, тінкторіальних, ку-льтуральних та біохімічних властивостей, продукувати характерні еметичний (блювотний) і ентеротоксини. Молеку-лярно-генетична діагностика і виявлення токсинпродукучої здатності виділених 42 штамів Bacillus cereus показали як можливість їх швидкої ідентифікації, так і наявність характерних генів токсичності. Мультиплексну полімеразну лан-цюгову реакцію (ПЛР) проводили зі специфічними праймерами для вияв...

Epiphytic and regulated microbial contaminants of food vegetable raw materials and products

“…The presence of aerobic bacillus does not always cause a significant change in the organoleptic properties of canned products. In some countries Bacillus subtilis are used as probiotics.However, analysis of the literature suggests the presence among them of microorganisms with toxigenic properties even in acceptable residual canned microbiota, which may lead to reduced immunity and cause various diseases in humans [19][20][21]. According to the information in Table 4, their high thermal stability contributes to their survival after technological processing of raw materials.…”

Methodology for accelerated monitoring and assurance of sanitary quality and food safety

“…Biological hazards are the main ones in assessing the degree of risk if they are caused by the presence of microorganisms in foodstuffs such as bacteria or products of their vital activity, toxigenic molds, viruses; parasites -helminths and protozoa, as well as insects that are potential carriers of pathogenic microorganisms [1,2,3]. According to statistics, annual economic losses due to diseases caused by several pathogenic microorganisms in the US amount to 35 billion dollars, in Australia -up to 2.6 billion Australian dollars, and social losses are irreplaceable [4,5]. The reason for increasing the level of biological hazards is the modern fashion for the consumption of raw or minimally cooked food, the increase in the share of products of animal origin, improperly prepared or stored long before consumption, through the expansion of international trade in new types of food raw materials that have changed the overall a picture of microbiological hazards, a modification of the microorganisms themselves [5][6][7].…”