Collaborative Study of the Extraction of Light Filth from Canned Whole and Cream Style Corn

1973 ◽  
Vol 56 (3) ◽  
pp. 634-636
Author(s):  
Russell G Dent

Abstract An improved method has been developed for canned whole and cream style corn to replace 40.104. The proposed method is unique because the microscopic and macroscopic examinations can be conducted almost concurrently; in the official method the macroscopic examination is dependent upon completion of the microscopic examination. The proposed method is shorter and it eliminates the use of viscous castor oil by specifying extraction in a percolator with paraffin oil from hot 40% isopropanol. Glassware is easily cleaned up after percolator cycles with isopropanol and water rinses. The proposed method yielded improved recoveries of insect and rodent filth spike elements. The method has been adopted as official first action.

1971 ◽  
Vol 54 (3) ◽  
pp. 571-572
Author(s):  
J J Thrasher

Abstract Collaborative results are presented on a new method for light filth in ground chicory. A comparison of the new method and the official method, 40.007(b), indicates that recoveries of spiked larvae and adult insects were approximately equal for the 2 methods. However, average recovery of rodent hairs by the proposed method was 86% while rodent hair recovery by the official method was 55%. The new method utilizes detergent digestion and wet sieving followed by flotation with paraffin oil from 40% isopropanol. It is less time consuming to perform and cleaner filter papers are obtained. The new method has been adopted as official first action.


1981 ◽  
Vol 64 (1) ◽  
pp. 191-193
Author(s):  
Clarence C Freeman ◽  
◽  
J Nagy ◽  
P Schafer ◽  
W A Senff ◽  
...  

Abstract An improved method has been developed for extracting light filth from corn meal. The proposed method uses only tap water, salt, olive oil, and alcohol, eliminating the need for costly and toxic solvents for the separation. Reports from 8 collaborators showed that recovery was 95.8% for insect fragments and 84.3% for rodent hairs by the proposed method, as compared with 90.6 and 88.6%, respectively, by the official method. The proposed method has been adopted as official first action to replace official method 44.042 for corn meal only.


1986 ◽  
Vol 69 (4) ◽  
pp. 712-713
Author(s):  
Mary-Ann Gardiner ◽  
Diane McClymont Peace

Abstract An official AOAC method for detection of total filth in hard and soft cheese was modified to (a) achieve digestion of cheese at lower cost, (b) improve filtration rates, and (c) facilitate microscopic examination of the filth collected. The modifications involve a wet-sieving step, a reduction in the amounts of liquid filtered and pancreatin used, a detergent defatting step, and an acid boil step, if required. Average recoveries ranged from 85 to 100%. The method modifications should be collaboratively studied so changes in the official method can be recommended


1985 ◽  
Vol 68 (5) ◽  
pp. 899-901
Author(s):  
Russell G Dent ◽  
Larry Glaze

Abstract Ihe present method for filth in unground marjoram is conducted in 2 parts. The first of these, which is for heavy filth and sand, requires the spice to be boiled with petroleum ether, then floated off with chloroform and, if needed, carbon tetrachloride. The second part, which is for light filth, is dependent on completion of the heavy filth section. After the spice is air-dried, the light filth is extracted with heptane and water. The proposed method was developed to make light filth independent of heavy filth analysis, improve filth recoveries, and reduce microscopic examination time. The light filth is extracted by ethanol defatting followed by a combination 15-60% ethanol/mineral oil extraction in a Wildman trap flask. Tween 80-NaEDTA solution is added to the trapping system to reduce the rising of excess plant material to the trap interface. The official method (AOAC 13th edition sees 44.142,44.120(b)) produced an average of 8 extraction papers per test portion and microscopic examination took an average of 88 min per test portion. The official method gave average recoveries of 14% for rodent hairs and 26% for insect fragments with 2 spike levels of 15 and 30 for each filth element. Recoveries of the 2 levels of each spike were not significantly different (P > 0.05). The proposed method gave average recoveries of 73% for rodent hairs and 70% for insect fragments. The proposed method has been adopted official first action to replace AOAC 13th edition sees 44.142 and 44.120(b) for unground marjoram only


1981 ◽  
Vol 64 (6) ◽  
pp. 1408-1410
Author(s):  
Richard L Trauba

Abstract An improved method has been developed for determining internal insect infestation of wheat kernels. The method involves acid hydrolysis of cracked wheat, wet sieving to remove the acid, transferring to a 2 L Wildman trap flask, deaeration by boiling, and treatment with Tween 80-Na4EDTA. Insects are extracted with light mineral oil. Reports from 6 collaborators showed that recovery was 95.92% for adult insect heads and 97.22% for larvae by the proposed method as compared with 87.05% and 6.12%, respectively, by the official method. The method has been adopted official first action.


1972 ◽  
Vol 55 (1) ◽  
pp. 62-63
Author(s):  
John S Gecan ◽  
Paris M Brickey

Abstract The official AOAC method for filth in starches, 40.056, has been modified to obtain better recovery of extraneous materials. In lieu of wet sieving on a No. 140 sieve, the modified method utilizes No. 230 wet sieving followed by an acid hydrolysis, if excessive starch material remains on the sieve. A limited collaborative study comparing the improved method with the official method resulted in higher recoveries of rodent hairs and equivalent recoveries of other spike elements by the improved method. The improved method is recommended for adoption as official first action to replace 40.056.


1972 ◽  
Vol 55 (3) ◽  
pp. 549-556
Author(s):  
J H Kahn ◽  
E T Blessinger

Abstract Fifteen chemists participated in a collaborative study for the quantitative pas-liquid chromatographic determination of the individual fusel alcohols and ethyl acetate in whisky. Two levels of congeners represented by 4 coded samples of whisky were analyzed by using t h e proposed method, employing a glycerol-1,2,6-hexanetriol column, and the official AOAC method, 9.063-9.065. Since isobutyl and the atnyl alcohols comprise by far the greatest part of fusel oil, their determination is of major importance to the total fusel oil content . Statistical analyses show that the proposed method is superior to the AOAC method for the determination of these alcohols, whereas the official method is superior for the determination of ethyl acetate and n-propyl alcohol. In general, collaborators employing modern instrumentation preferred the proposed method over the AOAC method. The former method also separates and permits the quantitative measurement of active amyl and isoamyl alcohols. The proposed method has been adopted as official first action as an alternative to 9.063–9.065 for the determination of higher alcohols and ethyl acetate in whisky.


1997 ◽  
Vol 80 (6) ◽  
pp. 1235-1271 ◽  
Author(s):  
Jane E Fox Dobson ◽  
Foster D McClure ◽  
Alvin P Rainosek ◽  
K Dashiell ◽  
J Fox Dobson ◽  
...  

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.


1996 ◽  
Vol 79 (4) ◽  
pp. 907-916 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming

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.


1978 ◽  
Vol 61 (2) ◽  
pp. 299-306
Author(s):  
Paul R Rexroad ◽  
Gary F Krause

Abstract A modified comprehensive nitrogen method, using 0.4 g C11SO4 as catalyst, is presented. This method plus a modified Raney powder method (mercury-free) with no metallic oxidation catalyst are compared with the AOAC comprehensive nitrogen method. Results from 19 collaborating laboratories for 11 samples are evaluated. The modified Raney method gave significantly low results on 2 samples: 21-7-14 (nitric phosphates-non-sulfate sulfur) and tryptophan. The results for the average per cent nitrogen for 11 samples from the modified comprehensive nitrogen method were comparable to those from the official method at the 95 % probability level; the overall pooled standard deviations were also similar. In this collaborative study, the modified method (with copper) was equal in accuracy and precision to the official method (with mercury). The modified comprehensive nitrogen method has been adopted as official first action.


Sign in / Sign up

Export Citation Format

Share Document