Multiplex PCR method for the detection of human norovirus, Salmonella spp., Shigella spp., and shiga toxin producing Escherichia coli in blackberry, coriander, lettuce and strawberry.

A multiplex PCR method was developed for the simultaneous detection of murine norovirus (MNV-1) as a surrogate for human norovirus (HuNoV) GI and GII, Salmonella spp., Shigella spp., and Shiga toxin producing Escherichia coli (STEC) in fresh produce.

Lactococcus lactis subsp. cremoris strain JFR1 attenuates Salmonella adhesion to human intestinal cells in vitro.

Lactococcus lactis subsp. cremoris JFR1 has been studied in reduced fat cheese due to its ability to produce exopolysaccharides (EPS) in situ, contributing to improved textural and organoleptic properties. In this study, the effect of strain JFR1 on virulence gene expression and attachment of Salmonella to HT-29 human colon carcinoma cells was investigated.

Stability of Secondary and Tertiary Structures of Virus-Like Particles Representing Noroviruses: Effects of pH, Ionic Strength, and Temperature and Implications for Adhesion to Surfaces.

Loss of ordered molecular structure in proteins is known to increase their adhesion to surfaces. The aim of this work was to study the stability of norovirus secondary and tertiary structures and its implications for viral adhesion to fresh foods and agrifood surfaces. The pH, ionic strength, and temperature conditions studied correspond to those prevalent in the principal vehicles of viral transmission (vomit and feces) and in the food processing and handling environment (pasteurization and refrigeration).

Comparison of RNA extraction methods for the detection of a norovirus surrogate in ready-to-eat foods.

Four nucleic acid extraction methods were evaluated for the purpose of quantifying a norovirus surrogate (murine norovirus [MNV-1]) concentrated from different food samples. Simple (strawberries and lettuce) and complex (sliced turkey breast, soft-shell clams, and potato salad) food matrices were inoculated with a viral suspension containing high (4×10(5) PFU) or low (4×10(3) PFU) numbers of viral particles. MNV-1 was eluted using either the Pulsifier™ or repetitive pipetting.

Macromolecular trafficking between a vesicular arbuscular endomycorrhizal fungus and roots of transgenic tobacco.

The root system of transgenic tobacco plants expressing the enhanced green fluorescent protein (EGFP) under the control of the 35S cauliflower mosaic virus (CaMV) promoter, were colonized with the endomycorrhizal fungus Glomus intraradices. Translocation of EGFP protein from the root to the fungus was registered by light and confocal microscopy. Immunolocalization also showed the presence of EGFP in the mycelium of Glomus intraradices.

Inactivation of hepatitis A virus and norovirus surrogate in suspension and on food-contact surfaces using pulsed UV light (pulsed light inactivation of food-borne viruses).

This study was conducted to evaluate the inactivation of murine norovirus (MNV-1) and hepatitis A virus (HAV) by pulsed ultraviolet (UV) light. MNV-1 was used as a model for human norovirus. Viral suspensions of about 10(6) PFU/ml were exposed to pulses of UV light for different times and at different distances in a Xenon Steripulse device (model RS-3000C).

Heat inactivation of hepatitis A virus and a norovirus surrogate in soft-shell clams (Mya arenaria).

The effectiveness of different thermal treatments for inactivating two viruses in clams was evaluated. Soft-shell clam digestive glands experimentally contaminated with hepatitis A virus (HAV) or murine norovirus (MNV) were heated for 90, 180, or 300 seconds at 85°C or 90°C in glass vials or plastic bags with 200 g of soft-shell clam meat. Inactivation was measured by plaque assay and real-time reverse-transcription (RT)-polymerase chain reaction assay.

Simultaneous separation and detection of hepatitis A virus and norovirus in produce.

Two sample preparation methods based on electrostatic binding were tested to simultaneously separate different viral particles from different food surfaces (lettuce, strawberry, raspberries and green onions). Both methods were evaluated using a multiplex real-time PCR assay designed for detection of hepatitis A virus and norovirus GI and GII. Single and multiplex detection limits were determined as 10(1) viral particles for HAV and norovirus GII, and 10(2) viral particles for norovirus GI using artificial templates, one HAV strain and different norovirus isolates.

Anion-exchange filtration and real-time PCR for the detection of a norovirus surrogate in food.

In the present study, nanoalumina filters were used as a sample preparation step for the concentration of a norovirus surrogate (murine norovirus 1) from food, and this was coupled with a two-step, real-time reverse transcriptase PCR for quantification. The nanoalumina medium was provided in a syringe-filter format, and its binding and elution capacities were tested with different buffers. Among the binding buffers tested (0.

Immunocapture and real-time PCR to detect Campylobacter spp.

In this work, the feasibility of using a large-volume immunocapture system as a sample pretreatment before detection of Campylobacter was studied. Real-time PCR was used for detection of captured cells after immunocapture. This immunocapture system is able to process high-volume samples by recirculation, increasing the possibility of capturing cells in low numbers.