Hepatitis A virus – a general overview

Hepatitis A virus infection occurs globally and is causing a public health concern, primarily in developing countries due to its persistent circulation in the environment. The improved sanitary condition and increase in awareness of personal hygiene have led to the marked reduction of HAV prevalence in industrialized countries during childhood and to a shift of the infection towards adulthood. HAV is an environmentally stable, positive single stranded RNA virus that is primarily transmitted by the fecal-oral route, person to person contact or ingestion of contaminated food and drink. One of the main causes leading to HAV infection is epidemiologically linked to the consumption of raw or undercooked shellfish particularly oysters and clams. Due to their filter-feeding style, these shellfishes readily concentrate viruses from the surrounding water containing municipal sewage, and as a consequence pose a health threat to consumers. Therefore, development of detection techniques possessing the requisite sensitivity and specificity for the practical routine monitoring purposes is of great importance necessary for the protection of shellfish-consuming public. Nucleic acid based method such as reverse transcription PCR has emerged as the popular method of choice in view of its rapidity, accuracy and sensitivity in contrary of the time-consuming conventional cell culture and hybridization techniques. However, detection of hepatitis A virus is firstly hampered by the non-cytophatic effect of wild type HAV strain, secondly, the low concentration of viral genome present in the environmental sample which requires effective isolation and concentration of virions and lastly the labor-extensive purification and thorough removal of the abundance of the PCR inhibitors which will unfavorably reduce the efficiency of PCR detection

Application of molecularly imprinted polymers in food sample analysis – a perspective

Since the introduction of the molecularly imprinting technology (MIT) in 1970s, it becomes an emerging technology with the potential for wide-ranging applications in food manufacturing, processing, analysis and quality control. It has been successfully applied in food microbiology, removal of undesirable components from food matrices, detection of hazardous residues or pollutants and sensors. Molecularly imprinted solid-phase extraction (MISPE) is the most common application so far. The review describes the methods of making the molecularly imprinted polymer systems, the application of the technology in food safety issues and the remaining challenges

Surface plasmon resonance biosensor for real-time detection of genetically modified organisms

Application of surface plasmon resonance (SPR) biosensor in detection of genetically modifed organism (GMO) is demonstrated. A total of four biotinylated probes namely Tnosb, P35Sb, LECb and TSQb were successfully immobilized onto the SA chip. Results analysis indicated that the SPR system with the sensor chip immobilized with the Tnosb, P35Sb, LECb and TSQb biotinylated probes potentially detect complementary standard fragments as low as 1 nM. Biospecifc interaction analysis (BIA), employing surface plasmon resonance (SPR) and biosensor technologies provide easy, rapid and automatable approach in detection of GMOs. Short assay times, label free DNA hybridization reaction and no toxic compounds are required, i.e. ethidium bromide, and the reusability of the sensor surface are some of the factors that contribute to the general advantages of the surface plasmon resonance (SPR) biosensor system in detection of GMOs

Natural occurrence of ochratoxin A contamination in commercial black and white pepper products.

The concentration of ochratoxin A (OTA) in 120 commercial pepper (84 pre-packed and 36 bulk samples), which consist of local and imported white and black pepper in powder and seed form in Malaysia were determined. The objective of the study was to investigate and compare OTA concentration in black pepper and white pepper being commercialized in Malaysia. Determination method was based on HPLC with fluorescence detection coupled with immunoaffinity column clean-up step. Mobile phase consisted of acetonitrile-water-acetic acid (49.5:49.5:1.0, v/v/v), and flow rate was 1 ml/min. The LOD was 0.02 ng/g, and the average recovery values of OTA ranged from 79.5 to 92.0% in black pepper and 81.2-90.3% in white pepper. A total of 57 samples (47.5%) were contaminated with OTA ranging from 0.15 to 13.58 ng/g. The results showed that there was a significant difference between type of pepper and brands. OTA concentration in black pepper was significantly higher than white pepper (p < 0.05). The highest concentration of ochratoxin, 13.58 ng/g, was detected in a sample of black pepper seed followed by 12.64 ng/g in a sample of black pepper powder, both were bulk samples purchased from open market

Pre-enrichment effect on PCR Detection of Salmonella Enteritidis in artificially-contaminated raw chicken meat

Salmonella remains to be a major foodborne pathogen for animals and humans and is the leading cause of foodborne infections and outbreaks in various countries. Salmonella Enteritidis is one of the most frequently isolated serotypes in poultry and poultry products from human food poisoning cases. It can cause mild to acute gastroenterititis as well as other common food poisoning symptoms when infection takes place in human. Nucleic acid amplification technologies such as Polymerase Chain Reaction (PCR) is a tool that is rapid and sensitive for detection of bacterial pathogen. We report the successful detection of S. Enteritidis by PCR in raw chicken meat artificially-contaminated with serial concentration of S. Enteritidis using crude DNA extracts as DNA template. PCR primers, ENT-F and ENT-R targeted on sdfI gene were used to amplify DNA region unique to S. Enteritidis with crude DNA extract of the samples, yielded product with the size of 303 bp. These primers were specific to S. Enteritidis when tested by in-silico simulation against genome database of targeted bacterial species and confirmed in PCR as amplification bands were observed with S. Typhimurium, S. Polarum and S. Gallinarum. The established PCR can detect as few as 9.4 X 101 CFU/ml of inoculated S. Enteritidis concentration and proved that pre-enrichment effect have significant effect on PCR detection by increasing 1000-fold of the sensitivity limit compared to the non pre-enriched samples. The PCR technique indicated that it can be successfully coupled with pre-enrichment step to offer advantage in routine screening and surveillance of bacterial contamination in food samples