scholarly journals Determination of Fish Flesh Content in Frozen Coated Fish Products (Modification of AOAC Official Method 971.13): Collaborative Study

1997 ◽  
Vol 80 (6) ◽  
pp. 1235-1271 ◽  
Author(s):  
Jane E Fox Dobson ◽  
Foster D McClure ◽  
Alvin P Rainosek ◽  
K Dashiell ◽  
J Fox Dobson ◽  
...  
Keyword(s):  
Raw Materials ◽  
Collaborative Study ◽  
Processing System ◽  
Test Sample ◽  
Official Method ◽  
Fish Products ◽  
Fish Flesh ◽  
Aoac Official ◽  
Fully Cooked ◽  
Aoac Official Method

Abstract An intralaboratory1collaborative study evaluated a modified version of AOAC Official Method 971.13 for determining the fish flesh content (FFC) in frozen coated fish products by comparing it with the on-line method. Eleven collaborators analyzed 36 products (a total of 6336 test samples). Each product targeted one of 4 percent fish flesh (PFF) levels (35,50,65, and 80). Products were manufactured from one of 3 raw materials (fillet blocks, minced blocks, and natural fillets) and processed in one of 4 forms (sticks, portions, formed portions, and fillets) and one of 4 styles (raw breaded, batter-dipped, precooked, and fully cooked). Each “official” test sample was tracked through the processing system and weighed (1) before battering and/or breading and, depending on product style, before frying; and (2) after battering and/or breading and, depending on product style, after frying; so that it served as its own control.

scholarly journals Molar Absorptivities of Aflatoxins B1, B2, G1, and G2 in Acetonitrile, Methanol, and Toluene-Acetonitrile (9 + 1) (Modification of AOAC Official Method 971.22): Collaborative Study

1999 ◽  
Vol 82 (2) ◽  
pp. 251-258 ◽  
Author(s):  
Stanley Nesheim ◽  
Mary W Trucksess ◽  
Samuel W Page ◽  
J Greer ◽  
J M Hurley ◽  
...  
Keyword(s):  
Thin Layer ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Test Sample ◽  
The Other ◽  
Official Method ◽  
Uv Spectrum ◽  
Aoac Official ◽  
Identical Test ◽  
Aoac Official Method

Abstract Four laboratories participated in a mini-collaborative study of AOAC Official Method 971.22, Standards for Aflatoxins, Thin-Layer Chromatographic Method, to extend the method to 3 replacement solvents for benzene for calibration of standard afla- toxin solutions. Triplicate test sample vials, each containing 25 μg of the respective aflatoxin for each of the 4 aflatoxins and for each of the solvents, were prepared and sent to each collaborator. The collaborators dissolved the aflatoxin in each vial in 2 mL solvent, measured the UV spectrum, and reported the absorptivity maxima near 350 nm. The concentrations of the aflatoxins in the test samples were determined by dissolving identical test samples in benzene-acetonitrile (98 + 2) and following the procedure described in AOAC Official Method 971.22. These concentrations were, in turn, used to determine the molar absorptivities in the other 3 solvents (see Table 1). AOAC Official Method 971.22 has been modified to extend its applicability to 3 replacement solvents for benzene for calibration of standard aflatoxin solutions.

scholarly journals Comparison of Babcock and Ether Extraction Methods for Determination of Fat Content of Cream: Collaborative Study

1996 ◽  
Vol 79 (4) ◽  
pp. 907-916 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Extraction Method ◽  
Collaborative Study ◽  
Extraction Methods ◽  
Fat Content ◽  
Official Method ◽  
Ether Extraction ◽  
Aoac Official ◽  
The Difference ◽  
Aoac Official Method

Abstract A modified Mojonnier ether extraction method for determination of the fat content of cream was developed based on the method for milk (AOAC Official Method 989.05). The cream Babcock method (AOAC Official Method 920.111 B-C) was modified to harmonize with the milk Babcock method (AOAC Official Method 989.04) and to clarify procedural details. Using the AOAC collaborative study format, 10 laboratories tested 9 pairs of blind duplicate heat-treated cream samples with a fat range of 30-45% using both methods. The statistical performance (invalid and outlier data removed) was as follows: mean % fat = 37.932, sr = 0.125, sR = 0.151, RSDr = 0.330, RSDR = 0.398, r = 0.354, and R = 0.427 for the ether extraction method. For the Babcock method, mean % fat = 38.209, sr = 0.209, SR = 0.272, RSDr = 0.548, RSDR = 0.712, r = 0.592, and R = 0.769. Average test results for fat from the Babcock method were 0.277% (absolute fat) greater than for the Mojonnier ether extraction method. The difference between methods, as a percentage of the average fat content of the samples, was 0.73%. This agrees with differences observed between the 2 methods for milk when 10 to 17 laboratories tested 7 milk samples in blind duplicate at bimonthly intervals over a 4-year period (average difference 0.029% fat, 0.78% as a percentage of average fat content). The Mojonnier ether extraction and Babcock methods for fat in cream have been adopted by AOAC INTERNATIONAL. The new Babcock method replaced the AOAC Official Method 920.111 B-C.

scholarly journals Detection of Added Beet or Cane Sugar in Maple Syrup by the Site-Specific Deuterium Nuclear Magnetic Resonance (SNIF-NMR®) Method: Collaborative Study

2001 ◽  
Vol 84 (5) ◽  
pp. 1509-1521 ◽  
Author(s):  
Yves-Loïc Martin ◽  
N Christoph ◽  
A -I Blanch-Cortès ◽  
J Dennis ◽  
S Giraudon ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Isotopic Ratio ◽  
Collaborative Study ◽  
Cane Sugar ◽  
Official Method ◽  
Site Specific ◽  
Maple Syrup ◽  
Aoac Official ◽  
Aoac Official Method

Abstract Results of a collaborative study are reported for the detection of added beet or cane sugar in maple syrup by the site-specific natural isotope fractionation–nuclear magnetic resonance (SNIF-NMR®) method. The method is based on the fact that the deuterium content at specific positions of the sugar molecules is different in maple syrup from that in beet or cane sugar. The syrup is diluted with pure water and fermented; the alcohol is distilled with a quantitative yield and analyzed with a high-field NMR spectrometer fitted with a deuterium probe and fluorine lock. The proportion of ethanol molecules monodeuterated at the methyl site is recorded. This parameter (D/H)I is decreased when beet sugar is added and increased when cane sugar is added to the maple syrup. The precision of the method for measuring (D/H)I was found to be in good agreement with the values already published for the application of this method to fruit juice concentrates (AOAC Official Method 995.17). An excellent correlation was found between the percentage of added beet sugar and the (D/H)I isotopic ratio measured in this collaborative study. Consequently, all samples in which exogenous sugars were added were found to have a (D/H)I isotopic ratio significantly different from the normal value for an authentic maple syrup. By extension of what is known about plants having the C4 cycle, the method can be applied to corn sweeteners as well as to cane sugar. One limitation of the method is its reduced sensitivity when applied to specific blends of beet and cane sugars or corn sweeteners. In such case, the C13 ratio measurement (see AOAC Official Method 984.23, Corn Syrup and Cane Sugar in Maple Syrup) may be used in conjunction.

scholarly journals Assurance® Enzyme Immunoassay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.10): Collaborative Study

2002 ◽  
Vol 85 (5) ◽  
pp. 1037-1044 ◽  
Author(s):  
Philip T Feldsine ◽  
David E Kerr ◽  
Stephanie C Leung ◽  
Andrew H Lienau ◽  
Stephanie M Miller ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enzyme Immunoassay ◽  
Collaborative Study ◽  
Ground Beef ◽  
Culture Method ◽  
Enterohemorrhagic Escherichia Coli ◽  
Official Method ◽  
Escherichia Coli O157 ◽  
Aoac Official ◽  
Aoac Official Method

Abstract AOAC Official Method 996.10, Assurance® Enzyme Immunoassay (EIA) for Escherichia coli O157:H7 (EHEC), was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by EIA and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment conditions and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 14 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level where predominantly positive results were expected, and a low level where fractional recovery was anticipated. Collaborators tested 378 test portions and controls by both the 8 h EIA and the USDA/FSIS enrichment methods, for a total of 756 test portions. Of the 378 paired test portions, 75 were positive and 212 were negative by both methods. Thirteen test portions were presumptively positive by EIA and could not be confirmed culturally; 30 were negative by EIA, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the EIA method. There was no statistical difference between results obtained with the Assurance EIA for EHEC 8 h method and the culture method for raw ground beef. The Assurance EIA had a significantly higher recovery for cooked beef.

scholarly journals Visual Immunoprecipitate Assay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.09): Collaborative Study

2002 ◽  
Vol 85 (5) ◽  
pp. 1029-1036 ◽  
Author(s):  
Philip T Feldsine ◽  
David E Kerr ◽  
Stephanie C Leung ◽  
Andrew H Lienau ◽  
Ruth F Moser ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Collaborative Study ◽  
Culture Method ◽  
Enterohemorrhagic Escherichia Coli ◽  
Official Method ◽  
Escherichia Coli O157 ◽  
Culture Methods ◽  
Aoac Official ◽  
Inspection Service ◽  
Aoac Official Method

Abstract AOAC Official Method 996.09, Visual Immunoprecipitate Assay (VIP®) for Escherichia coli O157:H7, was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by VIP assay and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment procedure and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 15 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level, where predominantly positive results were expect d, and a low level where fractional recovery was anticipated. Collaborators tested 396 test portions and controls by both methods, for a total of 792 test portions. Of the 396 paired test portions, 75 were positive and 230 were negative by both the VIP and culture methods. Eleven test portions were presumptively positive by VIP and could not be confirmed culturally; 32 were negative by VIP, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the VIP method. There was no statistical difference between results obtained with the VIP for EHEC 8 h method and the culture method except for cooked beef, where the VIP had significantly higher recovery for one inoculation level.

scholarly journals Modification of Babcock Method to Eliminate Fat Testing Bias Between Babcock and Ether Extraction Methods (Modification of AOAC Official Methods 989.04 and 995.18): Collaborative Study

1997 ◽  
Vol 80 (4) ◽  
pp. 845-859 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Reference Method ◽  
Official Method ◽  
Test Results ◽  
Testing Bias ◽  
Ether Extraction ◽  
Relative Standard ◽  
Aoac Official ◽  
Aoac Official Method

Abstract The Babcock test for determining fat in milk (AOAC Official Method 989.04) and in cream (AOAC Official Method 995.18) gives consistently higher test results than does the modified Mojonnier ether extraction reference method (AOAC Official Methods 989.05 and 995.19). To decrease the density of material in Babcock columns and thus lower test results, the Babcock method was modified by lowering the temperatures used at various points in the method, from about 57.5° to 48°C. Using the AOAC collaborative study format, 9 laboratories tested 9 pairs of blind duplicate raw milk samples (fat range 2.5–5.7%) and 9 pairs of blind duplicate heat-treated cream samples (fat range 30–45%) using the temperature modified (TM) Babcock method. The ether extraction test was conducted as the reference method. The statistical performance (invalid and outlier data removed) of the TM Babcock method was, for milk: percent fat value of 4.110, repeatability standard deviation (sr) value of 0.037, reproducibility standard deviation (sR) value of 0.047, repeatability relative standard deviation (RSDr) value of 0.901% and reproducibility relative standard deviation (RSDR) value of 1.147%; and for cream: percent fat value of 37.555, sr value of 0.258, sR value of 0.353, RSDr value of 0.687% and RSDR value of 0.940%. The TM Babcock method performance was acceptable but not as good as that achieved in previous studies of the unmodified method. For the TM Babcock and ether methods, respectively, average percentages fat were 4.110 and 4.114 for milk, and 37.555 and 37.485 for cream. Temperature modification statistically eliminated the testing bias between methods. The tem-perature modifications of the Babcock methods for determination of fat in milk and cream (989.04 and 995.18) have been adopted revised first action by AOAC INTERNATIONAL.

Modified Immunodiffusion Method for Detection of Salmonella in Raw Flesh and Highly Contaminated Foods: Collaborative Study

1995 ◽  
Vol 78 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Donald W Warburton ◽  
Philip T Feldsine ◽  
Maria T Falbo-Nelson ◽  
J Ackerl ◽  
D Adamik ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Culture Method ◽  
The United States ◽  
Test Method ◽  
Official Method ◽  
Private Industry ◽  
Agreement Rate ◽  
Aoac Official ◽  
Raw Shrimp ◽  
Aoac Official Method

Abstract A total of 19 government and private industry laboratories in Canada and the United States participated in the collaborative study. Naturally contaminated ground poultry and animal meals, as well as inoculated raw shrimp, were examined for presence of Salmonella by both the modified immunodiffusion method and the Bacteriological Analytical Manual culture method, resulting in an agreement rate of 93.1%. The 2 methods are statistically equivalent for all food types at each inoculation level and for all lots of naturally contaminated foods evaluated in this study. The modification of the AOAC Official Method 989.13, immunodiffusion (1–2 TEST) method for detection of motile Salmonella in all foods, has been adopted revised first action by AOAC INTERNATIONAL.

scholarly journals Liquid Chromatographic Method for Determination of Vanillin and Ethyl Vanillin in Imitation Vanilla Extract (Modification of AOAC Official Method 990.25): Collaborative Study

1997 ◽  
Vol 80 (3) ◽  
pp. 564-570 ◽  
Author(s):  
Sidney Kahan ◽  
Dana A Krueger ◽  
R Berger ◽  
A Filandro ◽  
L R Hageman ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Official Method ◽  
Ethyl Vanillin ◽  
Liquid Chromatographic Method ◽  
Aoac Official ◽  
Liquid Chromatographic ◽  
Aoac Official Method

Abstract A collaborative study of a method for analysis of vanillin and ethyl vanillin in fortified and imitation vanilla flavors was performed. The method, which is an extension of AOAC Official Method 990.25, Vanillin, Vanillic Acid, p-Hydroxybenzaldehyde, and p-Hydroxybenzoic Acid in Vanilla Extract, Liquid Chromatographic Method, involves reversed-phase high-pressure liquid chromatography (LC) of the sample on a Cβ column with a water-methanol-acetic acid (89 + 10 + 1) mobile phase and UV detection at 254 nm. The method yields good recoveries of vanillin at 484 and 723 mg/100 mL and of ethyl vanillin from 37 to 400 mg/100 mL. For vanillin, repeatability (r) values were 8 mg/100 mL at a level of 155 mg/100 mL, 12 mg/100 mLat a level of 484 mg/100 mL, and 31 mg/100 mL at a level of 723 mg/100 mL. Reproducibility (R) values were 20 mg/100 mL, 55 mg/100 mL, and 137 mg/100 mL over the same range. For ethyl vanillin, r values were 2.4 mg/100 mL at a level of 37 mg/100 mL, 3.2 mg/100 mL at a level of 74 mg/100 mL, and 8.6 mg/100 mL at a level of 180 mg/100 mL. R values were 6.4 mg/100 mL, 5.4 mg/100 mL, and 22.0 mg/100 mL over the same range. AOAC Official Method 990.25 has been modified to include determination of ethyl vanillin in vanilla extract and artificial vanilla flavor.

scholarly journals Gas Chromatographic Method for Putrescine and Cadaverine in Canned Tuna and Mahimahi and Fluorometric Method for Histamine (Minor Modification of AOAC Official Method 977.13): Collaborative Study

1997 ◽  
Vol 80 (3) ◽  
pp. 591-602 ◽  
Author(s):  
Patricia L Rogers ◽  
Walter Staruszkiewicz ◽  
A Adams ◽  
B Atienza ◽  
R J Berg ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Official Method ◽  
Fluorometric Method ◽  
Canned Tuna ◽  
Relative Standard ◽  
Aoac Official ◽  
Standard Deviations ◽  
Ppm Level ◽  
Aoac Official Method

Abstract A collaborative study was conducted to test a modification to the AOAC fluorometric method for histamine (AOAC® Official Method 977.13) that substitutes 75% methanol as the extracting solvent. All other steps remain unchanged. The extracts prepared with 75% methanol were also used to collaboratively test a gas chromatographic (GC) method for determination of putrescine and cadaverine in seafood. In the GC method, the extracted diamines are converted to fluorinated derivatives, the reaction mixtures are passed through solid-phase extraction columns, and the derivatives are quantitated by electron capture GC after separation on an OV-225 column. Fourteen laboratories using the GC method for putrescine and cadaverine and 16 laboratories using the fluorometric method for histamine analyzed 14 canned tuna and raw mahimahi (including blind duplicates and a spike) containing 0.2-2.6 ppm putrescine, 0.6-9.1 ppm cadaverine, and 0.6-154 ppm histamine. At the 5 ppm level, recoveries ranged from 71 to 102% for putrescine and 77 to 112% for cadaverine; the respective repeatability relative standard deviations (RSDr) were 5.2 and 15%, and the respective reproducibility relative standard deviations (RSDR) were 8.8 and 18%. At the 50 ppm level, histamine recoveries ranged from 84 to 125%, RSDr was 3.6%, and RSDR was 9.4%. The GC method for determination of putrescine in canned tuna and cadaverine in canned tuna and mahimahi has been adopted first action by AOAC INTERNATIONAL, and the AOAC Official Method 977.13, Histamine in Seafood, Fluorometric Method, has been modified

Extension of the Validation of AOAC Official MethodSM 2005.06 for dc-GTX2,3: Interlaboratory Study

2012 ◽  
Vol 95 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Begoña Ben-Gigirey ◽  
María L Rodríguez-Velasco ◽  
Ana Gago-Martínez
Keyword(s):  
Collaborative Study ◽  
Paralytic Shellfish Poisoning ◽  
Official Method ◽  
Reference Laboratory ◽  
The European Union ◽  
Shellfish Poisoning ◽  
Precision Data ◽  
European Union Reference Laboratory ◽  
Aoac Official ◽  
Aoac Official Method

Abstract AOAC Official MethodSM 2005.06 for the determination of saxitoxin (STX)-group toxins in shellfish by LC with fluorescence detection with precolumn oxidation was previously validated and adopted First Action following a collaborative study. However, the method was not validated for all key STX-group toxins, and procedures to quantify some of them were not provided. With more STX-group toxin standards commercially available and modifications to procedures, it was possible to overcome some of these difficulties. The European Union Reference Laboratory for Marine Biotoxins conducted an interlaboratory exercise to extend AOAC Official Method 2005.06 validation for dc-GTX2,3 and to compile precision data for several STX-group toxins. This paper reports the study design and the results obtained. The performance characteristics for dc-GTX2,3 (intralaboratory and interlaboratory precision, recovery, and theoretical quantification limit) were evaluated. The mean recoveries obtained for dc-GTX2,3 were, in general, low (53.1–58.6%). The RSD for reproducibility (RSDr%) for dc-GTX2,3 in all samples ranged from 28.2 to 45.7%, and HorRat values ranged from 1.5 to 2.8. The article also describes a hydrolysis protocol to convert GTX6 to NEO, which has been proven to be useful for the quantification of GTX6 while the GTX6 standard is not available. The performance of the participant laboratories in the application of this method was compared with that obtained from the original collaborative study of the method. Intralaboratory and interlaboratory precision data for several STX-group toxins, including dc-NEO and GTX6, are reported here. This study can be useful for those laboratories determining STX-group toxins to fully implement AOAC Official Method 2005.06 for official paralytic shellfish poisoning control. However the overall quantitative performance obtained with the method was poor for certain toxins.

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