Archive of April, 2024

DNA-based diagnostic, such as Polymerase Chain Reaction (PCR) tends to overestimate the number of live cells because it will also measure the DNA from dead cells. This is because of the relatively long perseverance of DNA after cell death (e.g. up to 3 weeks). DNA extracted from a sample can originate from any cell, regardless of its metabolic state. Consequently, most DNA-based diagnostics cannot distinguish between live and dead bacteria, and this is a major drawback of the techniques. After processes such as pasteurization or disinfections, dead bacteria might be present. While the dead bacteria present no hazard it can...

The recall The Center of disease Control (CDC) and the US Food & Drug Administration (FDA) are investigating a multistate outbreak of Listeria monocytogenes infections in raw milk cheeses.  Six people from four states were hospitalized, and two people from Connecticut and Vermont died. One illness was reported in a newborn. The FDA found Ouleout cheese contaminated with L. monocytogenes. Epidemiological and laboratory data indicates that the source of the infections is the cheese made by Vulto Creamery of Walton, NY. Whole Genome Sequencing (WGS) performed on clinical isolates from all six ill people shows that the isolates are closely related genetically. This close genetic...

Why Rapid Methods? Rapid methods of pathogen testing have been gaining acceptance in the food industry. Recent advances in technology result in faster detection and identification of pathogens, more convenient, more sensitive, more reproducible, and more specific than conventional methods. The main reasons for their adaptation are because faster results mean: Faster intervention and corrective actions Fewer lost lots or reduced amount of product in a contamination event Faster reaction to a problem Improved throughput and reduced warehouse space Decreased manufacturing cycle through faster release of inventory Ability to link strains of pathogens to a specific case Accelerates root cause...

The blog about PCR and distinguishing between live and dead bacteria have drawn some comments as shown below: Gerold Schwarz You might have a look for Reagent D – we established a protocol for Enterobacteriaceae in instant milk formula and Yeast and Mold in dairy products – it works similar utilizing a halogen light in addition source to eliminate dead cells before amplification.  Gerold Schwarz Send the following additional Information: By: Dr. Gerold Schwarz, Produktmanager BIOTECON Diagnostics GmbH Elimination of DNA form dead cells prior a PCR-Setup: Reagent D is designed for the rapid elimination of DNA from dead cells to avoid...