Assessment of food safety using a new real-time PCR assay for detection and quantification of virulence factors of enterococci in food samples

A procedure based on quantitative real-time PCR was evaluated for the detection and quantification of Bacillus cereus spores. Several methods for DNA isolation, such as various heat treatments and germination solutions, were evaluated on spore suspensions of representative strains of the B. cereus group. Overall, the commercially available DNeasy tissue kit yielded the maximum amount of DNA. The procedure also was used to construct calibration curves for different food matrices, with a wide spore quantification range of 5 log units using serial dilutions of spore suspensions of B. cereus CECT 148T. The detection limit for B. cereus in artificially contaminated liquid egg and reconstituted infant formula was about 4 spores per reaction or 60 spores per ml. The newly developed methodology based on the DNeasy tissue kit and an SYBR Green quantitative real-time PCR assay is very suitable for the rapid and accurate detection and quantification of B. cereus group strains and their spores in food samples.

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Development of Rapid Real-Time PCR and Most-Probable-Number Real-Time PCR Assays To Quantify Enterotoxigenic Strains of the Species in the Bacillus cereus Group

Journal of Food Protection ◽

10.4315/0362-028x-70.12.2774 ◽

2007 ◽

Vol 70 (12) ◽

pp. 2774-2781 ◽

Cited By ~ 17

Author(s):

I-CHEN YANG ◽

DANIEL YANG-CHIH SHIH ◽

JAN-YI WANG ◽

TZU-MING PAN

Keyword(s):

Bacillus Cereus ◽

Real Time ◽

Real Time Pcr ◽

Food Samples ◽

Most Probable Number ◽

Pcr Assay ◽

Bacillus Cereus Group ◽

Probable Number ◽

Cooked Rice ◽

Group Detection

Members of the Bacillus cereus group may produce diarrheal enterotoxins and could be potential hazards if they enter the food chain. Therefore, a method capable of detecting all the species in the B. cereus group rather than B. cereus alone is important. We selected nhe as the target and developed a real-time PCR assay to quantify enterotoxigenic strains of the B. cereus group. The real-time PCR assay was evaluated with 60 B. cereus group strains and 28 others. The assay was also used to construct calibration curves for different food matrices and feces. The assay has an excellent quantification capacity, as proved by its linearity (R2 > 0.993), wide dynamic quantification range (102 to 107 CFU/g for cooked rice and chicken, 103 to 107 CFU/ml for milk, and 104 to 107 CFU/g for feces), and adequate relative accuracy (85.5 to 101.1%). For the low-level contaminations, a most-probable-number real-time PCR assay was developed that could detect as low as 100 CFU/ml. Both assays were tested with real food samples and shown to be considerably appropriate for B. cereus group detection and quantification.

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Detection of Peanut Allergen Traces with a Real Time PCR Assay - The Challenge to Protect Food-Allergic Consumers

Journal of Food Research ◽

10.5539/jfr.v7n1p32 ◽

2017 ◽

Vol 7 (1) ◽

pp. 32 ◽

Cited By ~ 2

Author(s):

Dimitra Houhoula ◽

Stamatios Koussissis ◽

Vladimiros Lougovois ◽

John Tsaknis ◽

Dimitra Kassavita ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Rapid Detection ◽

Food Products ◽

Molecular Techniques ◽

Food Allergens ◽

Pcr Assay ◽

Peanut Allergen ◽

Pcr Method ◽

Detection And Quantification

The aim of the present study was the implementation of molecular techniques in the detection and quantification of allergic substances of peanut in various kinds of food products, e.g., breakfast cereals, chocolates and biscuits that are frequently related to allergies. In some cases, the presence of peanuts can be due to contamination during production and are not declared on the label. A total of 152 samples were collected from supermarkets and were analysed by a Real Time PCR method. The results indicated that 125 samples (83,3%) were found positive in peanut traces but the most important finding is that from the 84 samples that had no allergen declaration for peanuts, 48 (57,1%) of them were found positive. In conclusion, Real Time PCR can be a very important tool for the rapid detection and quantification of food allergens.

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