Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

Abstract

Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products) were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF) and the FDA official (BAM) method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM) counts similar to those of the BAM (reference) method. Statistical analysis of the data (t-test) revealed no significant differences between the two methods for all foods tested. Regression analysis showed that there was a good fit linear relationship between the two methods for most of the commodities examined. Some difficulties were encountered during counting of the colonies on HGMF since the size of the grid is very small and the number of possible colonies per plate can reach 1600.

Accelerating sample preparation through enzyme‐assisted microfiltration of Salmonella in chicken extract

“…More recently, the use of endopeptidase for chicken extract has also been reported (Table ) . A use of hydrolytic enzymes for sample preparation prior to enumeration of viable microorganisms in foods is given for hydrophobic grid membrane filter (HGMF) . The enzymes facilitate filtration of food extracts, which would otherwise plug the HGMF filter grid, which consists of a square, 5 × 5 cm filter divided into 1,600 compartments of 0.0156 cm 2 each.…”

“…7,[15][16][17][18][19][20][21] A use of hydrolytic enzymes for sample preparation prior to enumeration of viable microorganisms in foods is given for hydrophobic grid membrane filter (HGMF). 22 The enzymes facilitate filtration of food extracts, which would otherwise plug the HGMF filter grid, which consists of a square, 5 3 5 cm filter divided into 1,600 compartments of 0.0156 cm 2 each. This pattern facilitates counting of a large number of colonies when the HGMF filter is placed on an agar plate with selective media.…”