Enumeration of Coliforms in Nonfat Dry Milk and Canned Custard by Hydrophobic Grid Membrane Filter Method: Collaborative Study

1983 ◽  
Vol 66 (4) ◽  
pp. 897-904
Author(s):  
Phyllis Entis ◽  
◽  
B W Ciebin ◽  
V Gipson ◽  
M Grahn ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reference Method ◽  
New Method ◽  
Filter Method ◽  
Official Method ◽  
Random Errors ◽  
Dry Milk ◽  
Membrane Filter Method ◽  
Nonfat Dry Milk

Abstract A collaborative study was conducted in 14 laboratories to evaluate the performance of the hydrophobic grid membrane filter method against the official final action method, 46.016, for enumeration of colif orms in foods. Twelve artificially contaminated samples of nonfat dry milk and canned custard were analyzed by each laboratory. The random errors (Sr2) associated with the hydrophobic grid membrane filter method were significantly lower than those of the official method, and the counts obtained by the new method fell within the 95% confidence interval of the reference method. The colif orm counts obtained by tiie hydrophobic grid membrane filter method did not differ significantly from those obtained by the reference method as measured by a 3-way analysis of variance. The new method has been adopted official first action.

Rapid Hydrophobic Grid Membrane Filter Method for Salmonella Detection in Selected Foods: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 555-564
Author(s):  
Phyllis Entis
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reference Method ◽  
Black Pepper ◽  
Poultry Meat ◽  
Filter Method ◽  
Dry Milk ◽  
Membrane Filter Method ◽  
Nonfat Dry Milk ◽  
Egg Powder

Abstract A collaborative study was carried out in 36 laboratories to validate a hydrophobic grid membrane filter method for rapid (2-3 days) Salmonella detection by comparing its performance against the AOAC/ BAM reference method. Six products were included in the study: semisweet chocolate, raw ground poultry meat, ground black pepper, cheese powder, egg powder, and nonfat dry milk. With the exception of the naturally contaminated poultry, all products were inoculated in advance with low concentrations of a variety of Salmonella serotypes. The hydrophobic grid membrane filter method detected the following numbers of positive samples (results of the AOAC/BAM reference method are shown in parentheses): chocolate, 67(68); raw ground poultry, 133(131); ground black pepper, 57(56); cheese powder, 81(80); egg powder, 51(45); and nonfat dry milk, 68(72). The 2 methods did not differ significantly at the 95% confidence level in any of the 6 foods. The hydrophobic grid membrane filter method has been adopted official first action for detection of Salmonella in selected foods.

Enumeration of β-Glucuronidase-Positive Escherichia coli in Foods by Using the ISO-GRID Method with SD-39 Agar

1998 ◽  
Vol 61 (7) ◽  
pp. 913-916 ◽  
Author(s):  
PHYLLIS ENTIS ◽  
IRINA LERNER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Reference Method ◽  
Grid Method ◽  
Test Method ◽  
Cottage Cheese ◽  
Filter Method ◽  
Official Method ◽  
Membrane Filter Method ◽  
Aoac Official

A study was undertaken to compare β-glucuronidase-positive Escherichia coli counts produced by the ISO-GRID hydrophobic grid membrane filter method using SD-39 agar (test method) with those produced by AOAC Official Method 990.11, an existing ISO-GRID method using lactose monensin glucuronate agar and buffered MUG agar (reference method). The methods were evaluated using 21 food products, with three independent lots of five replicate samples analyzed per product by both methods. The test and reference methods were statistically equivalent for 19 of the 21 products; frozen, raw ground lamb produced significantly higher counts using the reference method, whereas counts obtained from cottage cheese were significantly higher using the SD-39 agar-based method.

Enumeration of Total Coliforms, Fecal Coliforms, and Escherichia coli in Foods by Hydrophobic Grid Membrane Filter: Collaborative Study

1984 ◽  
Vol 67 (4) ◽  
pp. 812-823
Author(s):  
Phyllis Entis ◽  
◽  
B Bennett ◽  
M H Brodsky ◽  
D M Burgener ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Collaborative Study ◽  
Reference Method ◽  
Black Pepper ◽  
Fecal Coliforms ◽  
Filter Method ◽  
Total Coliforms ◽  
E Coli ◽  
Membrane Filter Method

Abstract A collaborative study was conducted in 18 laboratories to assess the performance of the hydrophobic grid membrane filter method against that of the AOAC official first action method 46.013-46.016 for enumerating total and fecal coliforms and Escherichia coli. The study was carried out on frozen breaded fish, raw comminuted poultry, unroasted walnut pieces, ground black pepper, and cheddar cheese. The hydrophobic grid membrane filter method recovered significantly larger numbers of target bacteria in 7 of the food/analysis combinations: fecal coliforms in fish; E. coli in poultry; fecal coliforms and E. coli in walnuts; and total coliforms, fecal coliforms and E. coli in black pepper. Random error (Sr2) associated with the hydrophobic grid membrane filter method was significantly lower than that of the reference method in over 30% of the paired sample series. The hydrophobic grid membrane filter method for total coliform, fecal coliform, and E. coli enumeration in foods has been adopted official first action.

scholarly journals Two-Day Hydrophobic Grid Membrane Filter Method for Yeast and Mold Enumeration in Foods Using YM-11 Agar: Collaborative Study

1996 ◽  
Vol 79 (5) ◽  
pp. 1069-1082 ◽  
Author(s):  
Phyllis Entis ◽  
A Athar ◽  
M Ballenger ◽  
M S Bendeck ◽  
W Birbari ◽  
...  
Keyword(s):  
Orange Juice ◽  
Membrane Filter ◽  
Collaborative Study ◽  
Ground Beef ◽  
Reference Method ◽  
Test Method ◽  
Filter Method ◽  
Garlic Powder ◽  
Reference Methods ◽  
Membrane Filter Method

Abstract Twenty laboratories participated in a collaborative study to validate a 2-day hydrophobic grid membrane filter method using YM-11 agar for enumeration of yeast and mold in foods. Six naturally contaminated food products were included in the study: garlic powder, raw ground beef, walnuts, flour/meal, orange juice, and yogurt. The test method produced significantly higher results than the 5-day pour plate reference method for orange juice and significantly lower, though numerically similar, results for walnuts and yogurt. Differences between the test and reference methods were not significant for garlic powder, raw ground beef, or flour/meal. Repeatability and reproducibility were similar for both the test and reference methods in all cases. The hydrophobic grid membrane filter method for enumeration of yeast and mold in foods has been adopted by AOAC INTERNATIONAL.

Hydrophobic Grid Membrane Filter Method for Aerobic Plate Count in Foods: Collaborative Study

1986 ◽  
Vol 69 (4) ◽  
pp. 671-676 ◽  
Author(s):  
Phyllis Entis ◽  
◽  
J Allen ◽  
A Bhatnagar ◽  
A Brouwer ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Raw Milk ◽  
Plate Count ◽  
Filter Method ◽  
Membrane Filter Method ◽  
Aerobic Plate Count ◽  
Egg Powder ◽  
Raw Poultry ◽  
Whole Egg

Abstract Twenty-one laboratories participated in a collaborative study to validate a hydrophobic grid membrane filter (HGMF) method for aerobic plate count by comparing its performance against the AOAC/APHA pour plate method. Raw milk, raw poultry, whole egg powder, flours, and spices were included in the study. Counts obtained by the HGMF and pour plate methods did not differ significantly, except in the case of whole egg powder, for which the HGMF method produced significantly higher counts. The hydrophobic grid membrane filter method for aerobic plate count in foods has been adopted official first action.

Total Solids in Nonfat Dry Milk by Atmospheric Drying in a Forced Air Oven

1978 ◽  
Vol 61 (3) ◽  
pp. 550-557
Author(s):  
John W Sherbon ◽  
James B Mickle ◽  
William D Ward
Keyword(s):  
Collaborative Study ◽  
Milk Powder ◽  
Steam Bath ◽  
Official Method ◽  
Vacuum Oven ◽  
Drying Time ◽  
Total Solids ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
Forced Air

Abstract Laboratories using forced air atmospheric ovens at 100°C to determine total solids in milk are interested in using the same equipment to measure total solids in nonfat dry milk powder (NFDM). Results of several studies previously were presented to the Association. Another collaborative study involving 5 laboratories was done this year. The results of the new study confirm the previous work; the forced air method gives results not significantly different from the official vacuum oven procedure. Throughout these studies, it was noted that strong thermal gradients in some vacuum ovens made it difficult to uniformly subject each sample to the specified amount of heat. It was also found that fresh whole milk and reconstituted NFDM can be tested successfully when the steam bath step is omitted from the official method for milk by increasing the drying time to 4½ hr.

Collaborative study of the MPN, Anderson–Baird-Parker direct plating, and hydrophobic grid-membrane filter methods for the enumeration of Escherichia coli biotype I in foods

1983 ◽  
Vol 29 (10) ◽  
pp. 1247-1252 ◽  
Author(s):  
A. N. Sharpe ◽  
M. K. Rayman ◽  
D. M. Burgener ◽  
D. Conley ◽  
A. Loit ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Collaborative Study ◽  
Most Probable Number ◽  
Filter Method ◽  
Green Beans ◽  
Probable Number ◽  
Direct Plating ◽  
Filter Methods ◽  
Membrane Filter Method

Five Health Protection Branch laboratories compared two membrane filter methods (the Anderson–Baird-Parker direct plating, and a hydrophobic grid-membrane filter method) against the most probable number procedure (MPN) for enumerating Escherichia coli biotype I in foods. Results were available in 24 h by both membrane filter methods, compared with 10–14 days by the MPN procedure. For ground beef, Parmesan cheese, and cut green beans, the hydrophobic grid method generally gave the highest recovery, although the two membrane filter methods were not significantly different. Both these methods gave significantly higher recoveries than the MPN procedure, and for most foods, either method would be preferable. Further work is required before either membrane filter method can be recommended for bean and alfalfa sprouts, which may contain very high levels of Klebsiella spp.

The Microbiological Quality of Honey as Determined by Aerobic Colony Counts

1993 ◽  
Vol 56 (4) ◽  
pp. 336-337 ◽  
Author(s):  
JOSEP SERRA BONVEHI ◽  
ROSSEND ESCOLÁ JORDÁ
Keyword(s):  
Membrane Filter ◽  
Microbiological Quality ◽  
Plate Count ◽  
Filter Method ◽  
Filter Methods ◽  
Plate Counts ◽  
Multifloral Honey ◽  
Plate Count Method ◽  
Membrane Filter Method

The number of mesophilic aerobic colonies was determined in 72 samples of mono- and multifloral honey from various sources by the plate count and the membrane filter methods. The presence of motile colonies made the plate counts unreliable. The microorganism producing these colonies was identified as Bacillus alvei. Colony counts could only be carried out in 27 of the samples when using the plate count method, while with the membrane filter method the number of colonies was counted in all the samples.

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