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  • Rapid and robust detection methods for poison and microbial contamination.

Rapid and robust detection methods for poison and microbial contamination.

Journal of agricultural and food chemistry (2012-05-29)
Melanie M Hoehl, Peter J Lu, Peter A Sims, Alexander H Slocum
ABSTRACT

Real-time on-site monitoring of analytes is currently in high demand for food contamination, water, medicines, and ingestible household products that were never tested appropriately. Here we introduce chemical methods for the rapid quantification of a wide range of chemical and microbial contaminations using a simple instrument. Within the testing procedure, we used a multichannel, multisample, UV-vis spectrophotometer/fluorometer that employs two frequencies of light simultaneously to interrogate the sample. We present new enzyme- and dye-based methods to detect (di)ethylene glycol in consumables above 0.1 wt % without interference and alcohols above 1 ppb. Using DNA intercalating dyes, we can detect a range of pathogens ( E. coli , Salmonella , V. Cholera, and a model for Malaria) in water, foods, and blood without background signal. We achieved universal scaling independent of pathogen size above 10(4) CFU/mL by taking advantage of the simultaneous measurement at multiple wavelengths. We can detect contaminants directly, without separation, purification, concentration, or incubation. Our chemistry is stable to ± 1% for >3 weeks without refrigeration, and measurements require <5 min.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Peroxidase from horseradish, Type I, essentially salt-free, lyophilized powder, ≥50 units/mg solid (using pyrogallol)
Sigma-Aldrich
β-Nicotinamide adenine dinucleotide, pkg of 50 mg (per vial)