Detection of B. Cereus and Some of Its Virulence Genes in Some Dairy Desserts and Children Diarrhea

Abstract

Key words: B. cereus, Dairy desserts, Diarrhea and virulence genesB. cereus is an opportunistic foodborne pathogen that is found in most of the cases to be responsible for food-borne outbreaks. This study aimed to detect and quantify B. cereus in dairy desserts that locally manufactured and sold in different localities in Qena city, also to take an image about the role that is may be played by these products in causing foodborne illness by detection of B. cereus in diarrheal samples collected from the same regions from which the food samples are obtained. A total of 120 samples of ice-cream, mahallbia, rice and milk and diarrhea (30 samples each) were examined for presence of B. cereus. The results obtained in this study revealed detection of B. cereus in 55.6 and 40% of dairy dessert and diarrhea samples, respectively. B. cereus could be counted in 30, 60 and 76.7% of ice-cream, mahallbia and rice and milk samples with mean values of 3.5× 10 4 ±1.5× 10 4 , 6.3×10 5 ±1.9×10 5 and 1.4×10 7 ±6.6× 10 6 CFU/g, respectively. The possibility of involvement of theses dairy dessert samples in food poisoning cases was reinforced especially after detection the virulence genes of B. cereus isolates. It was found that 80, 44 and 24% of B. cereus isolates recovered from food samples harbored nhe, hbl and cytK genes, receptively including 55.6, 33.3 and 0% for ice-cream isolates; 83.3, 50 and 44.4% for mahallbia isolates and 86.9, 43.5 and 17.4% for rice and milk isolates. While for diarrhea samples, 75% of B. cereus isolates obtained from diarrhea samples carried nhe and cytK, respectively and 50% were found to be positive for hbl gene. Neither of the isolates that obtained from dairy dessert nor those obtained from diarrhea samples was positive for presence of ces gene.

Prevalence of Bacillus cereus in some dairy desserts in Egypt

“…In this study Bacillus cereus has been isolated from 58% of pudding (mahallbia) samples with mean count of 8.38× 10 5 CFU/g and approximately similar results were reported by (13,17). Lower incidences have been reported 44% and 48% by (4,16) respectively but with lower mean value of 3.83×10 5 CFU/g (16).…”

“…CFU/g. Higher incidence has been recorded 76.6% with ahigher mean value of 1.4 ×10 7 ± 6.6 × 10 6 CFU/g by (13).lower results were recorded 64% with ahigher mean value of 2.4×107± 1.5× 107 CFU/g by (4). Lower incidences have been reported 60% ,55% , 48% ,35% and 15% from rice pudding samples by (32,27,16,30,17) respectively.…”

“…Much higher result 80% has been detected from examined mahallbia samples by (1). From the data in Table (4) it is obvious that the highest frequency distribution (34.4%) of pudding (mahallbia) samples was with the count range of (10 5 ≥ 10 6 CFU/g) lower than that recorded by (13) with the highest score (44.4%) of mahallbia samples in the same count range. Any of constituents may introduce Bacillus cereus contamination to the final products and many studies reported that Bacillus cereus could be isolated from raw milk (27) , from food containing corn starch (14).…”

“…Based on molecular examination of B. cereus isolates virulence genes of which are responsible for toxin production in rice pudding samples , it is clear that emetic toxin ces gene could be found in 22.2 % of the isolates which is ahigher incidence than obtained by (11) who reported that 1.1% of B. cereus tested were emetic toxin producers. The ces gene encoding cereulide has no incidence in the isolates obtained from food samples examined by (13,5,20).…”

Detection of the hbl complex genes in Bacillus cereus isolated from cow raw milk in northwest of Iran

“…Reis et al (15) reported that 36.5% of isolated B. cereus from pasteurized, sterilized and dry milk in Brazil had the hbl complex genes. In another study, El-zamkan and Mubarak in Egypt (16), has been reported that the frequency of the hbl complex genes in B. cereus isolated from ice cream and rice-milk was 33.3% and 43.5%, respectively (16). Differences in distribution of the hbl complex genes in different B. cereus isolates in the mentioned studies probably are due to the geographical differences and the differences in ecological origin of isolated strains from milk, rice, meat, salads.…”