Survival and Growth of Psychrotrophic Bacillus cereus in Dry and Reconstituted Infant Rice Cereal

Jaquette, C. B.; Beuchat, Larry R.

doi:10.4315/0362-028x-61.12.1629

Cited by 54 publications

(22 citation statements)

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“…Dried milk products, such as milk powder, infant milk formula and infant cereal products, contaminated with B. cereus should be considered as potential vehicle for foodborne B.cereus disease [19,20]. These products often contain high level of carbohydrates (starch, sucrose or lactose) and minerals which can promote proliferation and enterotoxin production when they are reconstituted and held at ambient temperature for extended periods, potentially even at refrigeration temperature [21][22][23]. Bacillus spp isolated were identified as B. cereus, B. licheniformis, Geobacillus stearothermophilus, B. subtilis, Brevi.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of Some Antibiotics Against Pathogenic Bacteria Isolated from Infant Foods in North Africa

Shadlia-Matug¹,

Aidoo²,

Candlish³

et al. 2009

TOFSJ

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Eighty four samples of commercial infant foods in Libya were examined for microbiological quality. Bacillus cereus, B. stearothermophilus, B. licheniformis, Staphylococcus xylosus, S.lentus, Enterobacter sakazakii, E. aerogenes were isolated from the samples. Over 64.3 % of the samples contained high counts of Bacillus spp ( 2 log 10 CFU/g), 42.9% Staphylococcus spp ( 2 log 10 CFU/g) and 26.3% Enterobacteriaceae ( 2 log 10 CFU/g). The moulds isolated were mainly of the genera, Aspergillus and Penicillium. In relation to antibiotic resistance Bacillus spp showed the highest level of resistance to bacittracin (63.6%), ampicillin (54.5%), cephalosporin (36.4%), penicillin (18.1%) and nalidixine acid (18.2%). Corresponding values for Staphylococcus spp were bacitracin 60%, erythromycin 30%, penicillin 30%, cephalosporin 10%, nalidixic acid 10% and ampicillin 10%, respectively. Enterobacteriaceae strains were resistant to bacitracin (100%), erythromycin (62.5%), ampicillin (37.5%), cephalosporin (25%) and nalidixine acid (12.5 %). Bacillus spp, Staphylococcus spp and Enterobacteriaceae were susceptible to chloramphenicol, kanamycin, gentamicin and streptomycin.

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Section: Resultsmentioning

confidence: 99%

Evaluation of Some Antibiotics Against Pathogenic Bacteria Isolated from Infant Foods in North Africa

Shadlia-Matug¹,

Aidoo²,

Candlish³

et al. 2009

TOFSJ

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“…Such food may pose a threat to consumers if the product has been temperature abused during shipment or storage or when psychrotrophic strains of Bacillus spp. predominate and grow to high densities prior to consumption (7,15,18,25,28,30).…”

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confidence: 99%

Enterotoxin Production in Natural Isolates of Bacillaceae outside the Bacillus cereus Group

Phelps

McKillip

2002

Appl Environ Microbiol

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Thirty-nine Bacillus strains obtained from a variety of environmental and food sources were screened by PCR for the presence of five gene targets (hblC, hblD, hblA, nheA, and nheB) in two enterotoxin operons (HBL and NHE) traditionally harbored by Bacillus cereus. Seven isolates exhibited a positive signal for at least three of the five possible targets, including Bacillus amyloliquefaciens, B. cereus, Bacillus circulans, Bacillus lentimorbis, Bacillus pasteurii, and Bacillus thuringiensis subsp. kurstaki. PCR amplicons were confirmed by restriction enzyme digest patterns compared to a positive control strain. Enterotoxin gene expression of each strain grown in a model food system (skim milk) was monitored by gene-specific reverse transcription-PCR and confirmed with the Oxoid RPLA and Tecra BDE commercial kits. Lecithinase production was noted on egg yolkpolymyxin B agar for all strains except B. lentimorbis, whereas discontinuous beta hemolysis was exhibited by all seven isolates grown on 5% sheep blood agar plates. The results of this study confirm the presence of enterotoxin genes in natural isolates of Bacillus spp. outside the B. cereus group and the ability of these strains to produce toxins in a model food system under aerated conditions at 32°C.Bacillus cereus is traditionally considered the most problematic member of the genus Bacillus to the food industry due to the ability of many strains to produce enterotoxins, a topic which has been reviewed recently (9,11,14,24). B. cereus may express at least two distinct multiple-component enterotoxins, the genes for which have been cloned and sequenced (13,16,29). A tripartite hemolytic heat-labile enterotoxin designated HBL is the product of an operon that includes hblA, hblD, and hblC, which encode the binding subunit (B) and the L 1 and L 2 lytic components, respectively (17, 29). Additionally, a nonhemolytic enterotoxin (NHE) operon has recently been characterized (13). The subunits of the B. cereus NHE also include two apparent lytic components, NH 1 and NH 2 , and a third gene product that remains uncharacterized. In addition, a third enterotoxin has been described that is composed of a single 41-kDa subunit (2). The exact role of this toxin, BceT, is still unclear compared to what is known about HBL and NHE subunit enterotoxins.Consumption of enterotoxigenic Bacillus spp. at high cell densities results in symptoms of diarrhea, with possible vomiting from a separate heat-stable emetic toxin (3, 10). Symptoms may appear 10 to 14 h following ingestion of foodstuffs contaminated with enterotoxigenic strains. Foods most often implicated in the diarrheal syndrome include poultry, cooked meats, soups, desserts, and occasionally fluid and dry milk products (19,20). The infective dose is high (ca. Ͼ10 6 CFU/g) because symptoms rely on the ingestion of the viable cells or spores, not the preformed toxin, in affected foods (12). Such food may pose a threat to consumers if the product has been temperature abused during shipment or storage or when psychrotrophic str...

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“…A similar growth trend was reported in a study of enterotoxigenic Bacillus cereus in infant rice cereal reconstituted with milk. 14 The pathogen, at an initial level of 2.1 log 10 CFU/ gram, reached populations of 7.1, 7.2, and 7.4 log 10 CFU/ gram, within 12, 48, and 72 hours when stored at 30°C, 21°C, and 15°C, respectively.…”

Section: Discussionmentioning

confidence: 94%

Survival and growth of Shigella flexneri, Salmonella enterica serovar enteritidis, and Vibrio cholerae O1 in reconstituted infant formula.

Beuchat²,

Doyle³

et al. 2002

Am J Trop Med Hyg

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Abstract. Formula feeding is an alternative method to prevent mother-to-child infection with human immunodeficiency virus through breast-feeding in developing countries. Growth of bacterial pathogens in reconstituted infant formula has become a health hazard when contaminated water is used for rehydration. This study was conducted to assess bacterial safety risk of using contaminated water to reconstitute infant formula. Survival and growth characteristics were determined for three bacterial pathogens, Vibrio cholerae O1, Shigella flexneri, and Salmonella enterica serovar Enteritidis, inoculated into sterile tap water (3.2-3.4 log 10 colony-forming units [CFU]/ml) and infant formula (1.5-1.7 and 3.2-3.4 log 10 CFU/ml) and incubated at 4°C or 30°C for up to 24 hours. Vibrio cholerae O1 was the most sensitive of the three pathogens when inoculated into water, with no viable cells detected within 2 hours at 4°C or 30°C. The rate of inactivation in water was greater at 30°C than at 4°C. Vibrio cholerae O1, Shigella flexneri, and Salmonella enterica serovar Enteritidis grew rapidly in infant formula at 30°C, reaching populations of 9.2, 8.7, and 9.2 log 10 CFU/ml, respectively, at 24 hours. Populations of all three pathogens did not change significantly after incubating infant formula for 24 hours at 4°C, but continuously decreased in water throughout incubation for 24 hours, regardless of temperature. Results suggest that unless refrigerated, reconstituted infant formula should be consumed soon after preparation to avoid increased risk of illness associated with increases in populations of pathogenic bacteria that may be introduced by contaminated water.

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Survival and Growth of Psychrotrophic Bacillus cereus in Dry and Reconstituted Infant Rice Cereal

Cited by 54 publications

References 0 publications

Evaluation of Some Antibiotics Against Pathogenic Bacteria Isolated from Infant Foods in North Africa

Evaluation of Some Antibiotics Against Pathogenic Bacteria Isolated from Infant Foods in North Africa

Enterotoxin Production in Natural Isolates of Bacillaceae outside the Bacillus cereus Group

Survival and growth of Shigella flexneri, Salmonella enterica serovar enteritidis, and Vibrio cholerae O1 in reconstituted infant formula.

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