NEO-GRID® disposable units and ISO-GRID® membranes are filtration systems used on food, beverage and water samples for the detection, confirmation and enumeration of microorganisms including yeast and mould, total plate counts, coliforms, generic E.coli, E.coli O157:H7, Salmonella, Listeria, Listeria monocytogenes, Staphylococcus and more.
ISO-GRID/NEO-GRID tests are based on the concept of hydrophobic grid membrane filtration. The filter membrane is embossed with hydrophobic ink to produce a grid containing 1600 individual squares. The ink’s hydrophobic nature contains the growth of an organism isolated during the filtration process within the square of capture.
Samples are first diluted in a sterile buffer. The ISO-GRID /NEO-GRID filtration unit then is placed onto a manifold connected to a vacuum source, and a sterile filter membrane is placed in the ISO-GRID filtration unit (NEO-GRID already contains a sterile filter membrane). Using the vacuum source, a portion of the diluted sample is filtered through the filter membrane.
The membrane is transferred to an agar plate prepared with a medium formulated to promote/differentiate the growth of the target organism. Following incubation, the plate’s squares containing presumptively positive colonies are counted to yield a most probable number (MPN) result.