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

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

Microbiological Quality of Various Medicinal Herbal Teas and Coffee Substitutes

Various herbal teas including German chamomile, Chrysanthemum Vascuflow herb tea, hop, jasmine and orange flowers, sweet marjoram, spearmint and thyme leaves, and papaya-mint tea as well as coffee substitutes (Bambu instant Swiss, Teeccino chocolate-mint, and Teeccino Mediterranean Espresso) were analyzed for fungal contamination and the presence of aerobic mesophilic bacteria (APC). The results of this investigation showed that fungal counts reached levels as high as 5.8 × 10 5 colony forming units (cfu) per gram. German chamomile harbored the highest fungal contamination. The most common fungi found in herbal teas were Aspergillus niger, Penicillium spp., Eurotium rubrum, E. chevalieri, A. flavus, Fusarium spp., Alternaria alternata , and yeasts. Among the coffee substitutes, only the chocolate-mint coffee was contaminated with low numbers (<1.0 × 10 3 cfu g -1 ) of E. rubrum, Ulocladium spp. and Phoma spp., and with yeasts (< 100–6.8 × 10 3 cfu g -1 ). Aerobic mesophilic bacteria were recovered from 100% of the herbal tea, chocolate-mint and Mediterranean Espresso, and from 50% of the Bambu instant Swiss coffee samples. The highest APC counts of 1.2 × 10 7 cfu g -1 were observed in spearmint leaves

Fungal Presence in Selected Tree Nuts and Dried Fruits

Sixty-four tree nut samples (almonds, pecans, pine nuts, and walnuts) and 50 dried fruit samples (apricots, cranberries, papaya, pineapple, and raisins) were purchased from local supermarkets and analyzed for fungal contamination using conventional culture as well as molecular methods. The results of our study showed that the highest yeast and mold (YM) counts (5.34 log 10 CFU g -1 ) were found in walnuts and the lowest in pecans. The most common mold in nuts was Aspergillus niger , relatively low numbers of A. flavus were found across the board, while Penicillium spp. were very common in pine nuts and walnuts. Low levels (2.00–2.84 log 10 CFU g -1 ) of yeasts were recovered from only two pine nut samples. Fungal contamination in dried fruits was minimal (ranging from <2.00 to 3.86 log 10 CFU g -1 ). The highest fungal levels were present in raisins. All papaya samples and the majority of cranberry, pineapple, and apricot samples were free of live fungi. The most common mold in dried fruits was A. niger followed by Penicillium spp. One apricot sample also contained low levels (2.00 log 10 CFU g -1 ) of yeasts

Fungal Presence in Selected Tree Nuts and Dried Fruits

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