Molecular quantitation and characterization of Vibrio cholerae from different seafood obtained from wetmarket and supermarket

Abstract: Vibrio cholerae still represents a significant threat to human health worldwide despite the advances in hygiene, consumer knowledge, food treatment and food processing. In Malaysia, statistics in year 2009 have shown that among the food and water borne diseases, food poisoning has the highest incidence rate of 36.17 per 100,000 populations and with a mortality rate of 0.01 per 100,000 populations. In this study, 22 seafood samples comprising of fish, squid, crustacean and mollusks purchased from wet market and supermarket were analyzed. The Most Probable Number (MPN) and real time PCR was used to enumerate the Vibrio cholerae in seafood sample. The results showed that MPN-real time PCR of the samples from wet market had a maximum of >1100 MPN/g compare to 93 MPN/g enumerated from the MPN plate. The MPN-real time PCR in the samples from supermarket indicated 290 MPN/g as compared to 240 MPN/g enumerated from the MPN plate. The standard curves showed that there was a good linear correlation between the Ct values. The minimum level of detection of Vibrio cholerae standard DNA at targeted gene was 3 x 10 -5 ng/μl

A simple, portable, electrochemical biosensor to screen shellfish for vibrio parahaemolyticus

An earlier electrochemical mechanism of DNA detection was adapted and specified for the detection of Vibrio parahaemolyticus in real samples. The reader, based on a screen printed carbon electrode, was modified with polylactide-stabilized gold nanoparticles and methylene blue was employed as the redox indicator. Detection was assessed using a microprocessor to measure current response under controlled potential. The fabricated sensor was able to specifically distinguish complementary, non-complementary and mismatched oligonucleotides. DNA was measured in the range of 2.0 × 10−8–2.0 × 10−13 M with a detection limit of 2.16 pM. The relative standard deviation for 6 replications of differential pulse voltammetry (DPV) measurement of 0.2 µM complementary DNA was 4.33%. Additionally, cross-reactivity studies against various other food-borne pathogens showed a reliably sensitive detection of the target pathogen. Successful identification of Vibrio parahaemolyticus (spiked and unspiked) in fresh cockles, combined with its simplicity and portability demonstrate the potential of the device as a practical screening tool