Occurrence and significance of<i>Bacillus cereus</i>and<i>Bacillus thuringiensis</i>in ready-to-eat food

Rosenquist, Hanne; Smidt, Lasse; Andersen, Sigrid Rita; Jensen, Gert B.; Wilcks, Andrea

doi:10.1016/j.femsle.2005.06.054

Cited by 125 publications

(93 citation statements)

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“…AlAshmawy et al (1996) reported lower incidence (64%) of samples were contaminated with B. cereus with a mean value of 2.4×10 7 ± 1.5× 10 7 CFU/g which is slightly lower than the mean count of B. cereus that we recorded. Antithetical findings recorded by Rosenquist et al, (2005) as they found that most of the desserts with milk and rice samples (95.1%) contained much lower B. cereus counts (<10 3 CFU/g) than those recorded by us and 3.1% of the samples harbored B. cereus in counts > 10 4 CFU/g. Li et al (2016) reported higher incidences of nhe (100%) and cytK(91.6) and lower incidence of hbl (4.2%) in B. cereus isolates obtained from cooked rice samples.…”

Section: Discussionmentioning

confidence: 55%

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

El‐Zamkan¹,

Mubarak²

2017

AJVS

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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.

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Section: Discussionmentioning

confidence: 55%

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

El‐Zamkan¹,

Mubarak²

2017

AJVS

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“…The bacterium B. thuringiensis has only in one case been associated with food poisoning (15), although the bacterium has the same genetic potential for producing enterotoxins as B. cereus. A recent study in our laboratory has shown that more than half of the isolated B. cereus-like strains from 40 ready-to-eat products at a Danish retail market in fact belonged to B. thuringiensis (22), indicating that this species could be the causative agent of some of the food-borne outbreaks earlier ascribed to B. cereus. Counts of B. thuringiensis above 10 4 CFU g Ϫ1 were found in some fruits and vegetables (22).…”

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confidence: 95%

“…A recent study in our laboratory has shown that more than half of the isolated B. cereus-like strains from 40 ready-to-eat products at a Danish retail market in fact belonged to B. thuringiensis (22), indicating that this species could be the causative agent of some of the food-borne outbreaks earlier ascribed to B. cereus. Counts of B. thuringiensis above 10 4 CFU g Ϫ1 were found in some fruits and vegetables (22). Whether the high counts originated from natural contaminants or residues of B. thuringiensis insecticides was not shown.…”

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confidence: 95%

“…However, the role of CytK is not yet fully understood, since recent studies have indicated the existence of two variants of CytK (4, 10), the one (CytK2) having a lower toxicity than CytK1, which caused the severe food poisoning case. Also, commercially used B. thuringiensis strains have been shown to harbor genes for HBL, NHE, and CytK, and the expression of components of the three-component enterotoxins HBL and NHE has also been established (8,16,22).Since methods for identification of B. cereus-like bacteria in food and clinical settings do not distinguish between B. cereus and B. thuringiensis, the presence of B. thuringiensis in food and the role of this organism in food poisoning are not well described. The bacterium B. thuringiensis has only in one case been associated with food poisoning (15), although the bacterium has the same genetic potential for producing enterotoxins as B. cereus.…”

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confidence: 99%

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Occurrence of Natural Bacillus thuringiensis Contaminants and Residues of Bacillus thuringiensis -Based Insecticides on Fresh Fruits and Vegetables

Frederiksen¹,

Rosenquist²,

Jørgensen

et al. 2006

Appl Environ Microbiol

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A total of 128 Bacillus cereus-like strains isolated from fresh fruits and vegetables for sale in retail shops in Denmark were characterized. Of these strains, 39% (50/128) were classified as Bacillus thuringiensis on the basis of their content of cry genes determined by PCR or crystal proteins visualized by microscopy. Random amplified polymorphic DNA analysis and plasmid profiling indicated that 23 of the 50 B. thuringiensis strains were of the same subtype as B. thuringiensis strains used as commercial bioinsecticides. Fourteen isolates were indistinguishable from B. thuringiensis subsp. kurstaki HD1 present in the products Dipel, Biobit, and Foray, and nine isolates grouped with B. thuringiensis subsp. aizawai present in Turex. The commercial strains were primarily isolated from samples of tomatoes, cucumbers, and peppers. A multiplex PCR method was developed to simultaneously detect all three genes in the enterotoxin hemolysin BL (HBL) and the nonhemolytic enterotoxin (NHE), respectively. This revealed that the frequency of these enterotoxin genes was higher among the strains indistinguishable from the commercial strains than among the other B. thuringiensis and B. cereus-like strains isolated from fruits and vegetables. The same was seen for a third enterotoxin, CytK. In conclusion, the present study strongly indicates that residues of B. thuringiensis-based insecticides can be found on fresh fruits and vegetables and that these are potentially enterotoxigenic.The gram-positive spore-forming bacterium Bacillus thuringiensis is ubiquitous in the environment and is closely related to the food-borne pathogen Bacillus cereus. The only difference between the two species is the ability of B. thuringiensis to produce parasporal crystalline inclusions, the so-called crystal proteins (Cry proteins) or ␦-endotoxins, which are plasmid encoded. These toxins have highly specific activity against certain insects (6, 23), especially within the orders Lepidoptera, Diptera, and Coleoptera (11), and B. thuringiensis is therefore of commercial interest. Plant protection products based on selected strains of B. thuringiensis are used worldwide in, e.g., the production of fruits and vegetables in greenhouses and in the field.The high specificity of the Cry proteins against insects is mainly due to specific receptors in the insect gut, which are not present in the mammalian gut. These toxins are therefore considered harmless to humans. However, B. thuringiensis strains are capable of producing a variety of other toxins and virulence factors that can affect humans, including the same diarrhea-causing enterotoxins as produced by B. cereus (12,13,20). The two best-characterized enterotoxins are hemolysin BL (HBL) and nonhemolytic enterotoxin (NHE), which are both three-component toxins requiring expression of all three genes for full virulence (17,19). A third enterotoxin, cytotoxin K (CytK), is a single-component toxin once reported to be involved in a severe food poisoning case that caused the deaths of three individuals (18). H...

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A Primer on the Extraordinary Efficacy and Safety of Bacterial Insecticides Based onBacillus Thuringiensis

Federici¹

2022

Good Microbes in Medicine, Food Production, Biotechnology, Bioremediation, and Agriculture

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Occurrence and significance ofBacillus cereusandBacillus thuringiensisin ready-to-eat food

Cited by 125 publications

References 47 publications

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

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

Occurrence of Natural Bacillus thuringiensis Contaminants and Residues of Bacillus thuringiensis -Based Insecticides on Fresh Fruits and Vegetables

A Primer on the Extraordinary Efficacy and Safety of Bacterial Insecticides Based onBacillus Thuringiensis

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