DETECTION OF HBLD TOXIN GENE BY BACILLUS CEREUS ISOLATED FROM MEAT CURRY FOOD SAMPLES IN MALAYSIAN RESTAURANTS

Marwan Msarah,Ahmed Alsier,Sahilah, A.M

doi:10.26480/ees.02.2020.68.72

Abstract

Bacillus cereus is a ubiquitous foodborne pathogen, can cause food poisoning, leading to infections, have two major types of food poisoning emetic and diarrheal. Foods rich in protein such as meat are associated with foodborne outbreaks of diarrhea caused by B. cereus. The aim of this study is to isolate and identify B. cereus from ready to eat (RTE) meat curry from restaurants in Malaysia and to detect hblD pathogenic gene of B. cereus isolates. Mannitol egg yolk polymyxin agar was used as a selective isolation medium. Commercially available kits and boiling methods were used for DNA extraction, samples acquired from restaurants were examined for the presence of Hemolysin BL gene by polymerase chain reaction (PCR). Among all isolates, twenty-four of B. cereus isolates detected for HBL enterotoxin production by the discontinuous pattern on HBL sheep blood agar then confirmed by biochemical tests. More than 58.33 % of the isolate showed discontinuous hemolysis pattern on HBl blood agar and 29.16% of the samples were shown positive for hblD gene that can cause diarrhea with the size of 807bp on gel. This study demonstrated that RTE meat curry was a potential source for entero-toxigenic B. cereus and the presence of the hblD toxin genes for the HBL complex in the isolates tested were highly associated. Therefore, these meat curry isolates should be regarded as potential toxin producers.

Highlights

Bacillus cereus is an aerobic spore forming bacterium that is commonly found in soil, dust, air, water and vegetables, and in many raw and processed foods as a meat product, milk, and rice
At the first week SERDANG restaurants samples scored the highest mean of the presumptive B. cereus and the second week KL SENTRAL restaurants samples is higher while KAJANG restaurants samples still lowest, perhaps this due to both SERDANG and KL SENTRAL areas is more crowded with people and the restaurants samples taken from is near the train station which means more contact with people that resulted in higher contamination than the samples collected from KAJANG restaurants which are less congested
The extensive distribution of Bacillus cereus with the thermal resistance of spores helps to explain the wide variety of foods that have been implicating in B. cereus foodborne illness outbreaks

Summary

Introduction

Bacillus cereus is an aerobic spore forming bacterium that is commonly found in soil, dust, air, water and vegetables, and in many raw and processed foods as a meat product, milk, and rice. B. cereus food poisoning may occur when foods are prepared and held without adequate refrigeration for several hours before serving with B. cereus reaching higher than 106 cells/g (Granum et al, 1996). Various reports implicate both B. subtilis and B. licheniformis as potential food poisoning agents (Kramer et al, 1989; Choma et al, 2002; Zeighami et al, 2020; Hauge, 1955; Rampal et al, 2984; Garofalo et al, 2020; Ncube et al, 2020; Beecher et al, 1995; Ali et al, 2017). According to the public health community that regular hand washing is one of the most effective defenses against the spread of foodborne illness and the action of monitoring food

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