Rapid Detection of Salmonella in Foods Using Real-Time PCR

2008 ◽  
Vol 71 (12) ◽  
pp. 2436-2441 ◽  
Author(s):  
CHORNG-MING CHENG ◽  
WEN LIN ◽  
KHANH THIEN VAN ◽  
LIEUCHI PHAN ◽  
NELLY N. TRAN ◽  
...  

Conventional methods for detection of Salmonella serovars in foods are generally time-consuming and labor intensive. A real-time PCR method has been developed with custom designed primers and a TaqMan probe to detect the presence of a 262-bp fragment of the Salmonella-specific invA gene. The method has been tested with a total of 384 field-isolated Salmonella serovars and non-Salmonella stock strains, as well as 420 U.S. Food and Drug Administration food samples, comprising a variety of food matrices. The method was highly specific in detecting Salmonella in spiked chili powder and shrimp samples, with a sensitivity of 0.04 CFU/g. In addition, the method is faster, more accurate, and less costly than the traditional U.S. Food and Drug Administration's Bacteriological Analytical Manual cell-culturing and the AOAC International–approved VIDAS methods to detect Salmonella in foods.

2013 ◽  
Vol 12 (3) ◽  
pp. 107-113 ◽  
Author(s):  
Jie Huang ◽  
Chun Gao ◽  
Xilai Ding ◽  
Shoufang Qu ◽  
Licheng Liu ◽  
...  

2017 ◽  
Vol 7 (1) ◽  
pp. 32 ◽  
Author(s):  
Dimitra Houhoula ◽  
Stamatios Koussissis ◽  
Vladimiros Lougovois ◽  
John Tsaknis ◽  
Dimitra Kassavita ◽  
...  

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.


2007 ◽  
Vol 70 (4) ◽  
pp. 1033-1036 ◽  
Author(s):  
JENNIFER L. BRZEZINSKI

The detection of potentially allergenic foods, such as sesame seeds, in food products is a major concern for the food-processing industry. A real-time PCR method was designed to determine if sesame seed DNA is present in food products. The PCR reaction amplifies a 66-bp fragment of the sesame seed 2S albumin gene, which is detected with a sesame-specific, dual-labeled TaqMan probe. This reaction will not amplify DNA derived from other seeds present in baked goods, such as pumpkin, poppy, and sunflower seeds. Additionally, this assay will not cross-react with DNA from several tree nut species, such as almond, Brazil nut, cashew, hazelnut, and walnut, as well as four varieties of peanut. This assay is sensitive enough to detect 5 pg of purified sesame seed DNA, as well as sesame seed DNA in a spiked wheat cracker sample.


2014 ◽  
Vol 62 (3) ◽  
pp. 304-316 ◽  
Author(s):  
Orsolya Erdősi ◽  
Katalin Szakmár ◽  
Olivér Reichart ◽  
Zsuzsanna Szili ◽  
Noémi László ◽  
...  

The incidence of outbreaks of foodborne listeriosis has indicated the need for a reliable and rapid detection of the microbe in different foodstuffs. A method combining redox potential measurement and real-time polymerase chain reaction (PCR) was developed to detectListeria monocytogenesin artificially contaminated raw milk and soft cheese. Food samples of 25 g or 25 ml were homogenised in 225 ml of Listeria Enrichment Broth (LEB) with Oxford supplement, and the redox potential measurement technique was applied. ForListeriaspecies the measuring time was maximum 34 h. The absence ofL. monocytogenescould reliably be proven by the redox potential measurement method, butListeria innocuaandBacillus subtiliscould not be differentiated fromL. monocytogeneson the basis of the redox curves. The presence ofL. monocytogeneshad to be confirmed by real-time PCR. The combination of these two methods proved to detect < 10 cfu/g ofL. monocytogenesin a cost- and time-effective manner. This method can potentially be used as an alternative to the standard nutrient method for the rapid detection ofL. monocytogenesin food.


2007 ◽  
Vol 70 (4) ◽  
pp. 1002-1006 ◽  
Author(s):  
BENJAMIN R. WARREN ◽  
HYUN-GYUN YUK ◽  
KEITH R. SCHNEIDER

This study investigated flow-through immunocapture (FTI), using the Pathatrix device, followed by plating on xylose lysine desoxycholate (XLD) agar (FTI-XLD) or analysis by real-time PCR (FTI-PCR) for the detection of Salmonella on smooth tomato surfaces and in potato salad and ground beef within 8 h. Food samples were inoculated with an appropriate dilution of a five-serovar Salmonella cocktail and enriched for 5 h. Following enrichment, samples were analyzed by the FTIXLD and FTI-PCR methods. Food samples were also analyzed by a modified U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) Salmonella culture method for comparison. Salmonella inoculated at 100 CFU per tomato or 100 CFU/25 g was detected by the FTI-XLD method in 6, 8, and 4 of 10 samples for tomatoes, potato salad, and ground beef, respectively. Salmonella inoculated at 100 CFU per tomato or 100 CFU/25 g was detected by the FTI-PCR method in 8, 9, and 9 of 10 samples for tomatoes, potato salad, and ground beef, respectively. The FTI-PCR method achieved significantly higher (P &lt; 0.05) detection of Salmonella on tomatoes, whereas the FTI-XLD method achieved significantly lower (P &lt; 0.05) detection of Salmonella in ground beef when compared with the modified BAM Salmonella culture method; however, all other comparisons to the modified BAM method were not significantly different. The FTI-XLD method demonstrated the ability to isolate presumptive Salmonella colonies up to 48 h faster than did the modified BAM Salmonella culture method.


2014 ◽  
Vol 58 (4) ◽  
pp. 533-539
Author(s):  
Artur Jabłoński ◽  
Dominika Borowska ◽  
Sylwia Zębek ◽  
Andrzej Kowalczyk ◽  
Arkadiusz Dors ◽  
...  

Abstract The aim of the study was to develop and validate a real-time PCR method, using a TaqMan probe, for quantification of Mycoplasma suis in porcine blood. No PCR signals with closely related non-haemotrophic mycoplasmas were obtained. The detection limit of PCR for plasmid combined with blood DNA was determined to be 103/reaction (5 μL of DNA) (1.2x105 target copies in 1 mL of blood). The linearity of real-time PCR (near 1) indicates its use as a quantitative method. Real-time and quantitative PCR were sensitive and specific for the detection and quantification of M. suis in the blood of animals with acute and chronic form of eperythrozoonosis. Developed quantitative PCR cannot be used to detect carrier animals with a small amount of M. suis in their blood. The validity of real-time PCR used in the studies was confirmed by the low inter- and intra-assay coefficients of variation. This fact confirms the applicability of the assay in other laboratories.


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