bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbiological Survey of Selected Imported Spices and Associated Fecal Pellet Specimens
Authors: Satchell Felicia B , Bruce Verneal R , Allen Geraldine , Andrews Wallace H , Gerber Harriet R
Published: February 2020

A microbiological survey was performed on 4 selected imported spices: black peppercorns, white peppercorns, coriander, and fennel seed. Aerobic plate count values ranged from 104 to 107 colonyforming units (CFU)/g for black and white peppercorns and from 103 to 105 CFU/g for coriander and fennel seed. Combined results of the 3-tube most probable number procedure and the API 20E kit indicated the presence of Escherichia coli in 4 test samples of black peppercorns, 1 test sample of white peppercorns, and 1 test sample of coriander. Two test samples of black peppercorns were positive for Salmonella contamination. Among the various Enterobacteriaceae isolated from the spices, Enterobacter cloacae and Klebsiella pneumoniae were found most frequently in all spice types. Of 18 mammalian and avian fecal pellets removed from the spices and analyzed microbiologically, E. coli was found in only 2 pellet specimens. There was no apparent relationship between the enteric microflora found in spices and those found in the fecal pellets.
Urea Enzymatic Dialysis Procedure for Determination of Total Dietary Fiber
Authors: Jeraci Joseph L , Lewis Betty A , Peter J , Soest Van J , Robertson James B
Published: February 2020

A method that uses urea and enzymes for determination of total dietary fiber (TDF) in foods has been developed and compared with the AOAC enzymatic-gravimetric method (43.A14-43.A20). In the evaluation, results for crude protein and ash contamination were higher by the AOAC method, particularly for samples that form gels during ethanol precipitation. The new urea enzymatic dialysis (UED) method quantitatively recovered, with less variation, more of the purified and semipurified dietary fiber products. TDF recoveries for carboxymethylcellulose and locust bean gum were 98% (SD 3.3) and 95% (SD 6.1) by the AOAC method and 99% (SD 1.0) and 100% (SD 0.6) by the UED method, respectively. The UED method was the more effective in removing starch. For kale samples, starch recovery was 3.5 and 0.2% from TDF residues obtained using the AOAC and UED methods, respectively. Differences were not significant among replicate values for determination of TDF in foods by the UED method (P >0.01). Preliminary studies suggest that the new method can separately determine soluble and insoluble dietary fiber. The data indicate that the UED method is more precise and accurate than the AOAC method.
Evaluation of Various Methods for Measurement of Pectin Content in Jam
Authors: Lane Ralph H , Phillips John G
Published: February 2020

Substitution of toluene for benzene as part of the titration medium specified in the AOAC method for fat acidity (14.069-14.071) was evaluated by 3 laboratories. Blind duplicate samples of 5 commercially available flours were extracted with petroleum ether. The extracts were evaporated to dryness and dissolved in the titration medium containing equal volumes of 95% alcohol and benzene or toluene. Samples were then titrated with standard KOH to the end point of phenolphthalein. The data obtained showed no difference (P > 0.05) between the 2 solvents with respect to fat acidity means. The range of values for repeatability and reproducibility for both solvents was similar. These data indicate that toluene may replace the more toxic benzene. This change has been adopted as a revision in method 14.069-14.071.
Rapid Bacteriological Screening of Cosmetic Raw Materials by Using Bioluminescence
Authors: Nielsen Peter , Dellen Eric Van
Published: February 2020

Incoming cosmetic raw materials are routinely tested for microbial content. Standard plate count methods require up to 72 h. A rapid, sensitive, and inexpensive raw material screening method was developed that detects the presence of bacteria by means of ATP (bioluminescence). With a 24-h broth enrichment, the minimum bacterial ATP detection threshold of 1 cfu/g sample can be achieved using purified firefly luciferin-luciferase and an ATP releasing reagent. By using this rapid screen, microbiologically free material may be released for production within 24 h, while contaminated material undergoes further quantitative and identification testing. In order for a raw material to be validated for this method it must be evaluated for (I) a potential nonmicrobial light-contributing reaction resulting in a false positive or, (2) degradation of the ATP giving a false negative, and (J) confirmation that the raw material has not overwhelmed the buffering capacity of the enrichment broth. The key criteria for a rapid screen was the sensitivity to detect less than one colony forming unit per g product, the speed to do this within 24 h, and cost efficiency. Bioluminescence meets these criteria. With an enrichment step, it can detect less than one cfu/g sample. After the enrichment step, analysis time per sample is approximately 2 min and the cost for material and reagents is less than one dollar per sample.
Combination of Total Solids Determined by Oven Drying and Fat Determined by Mojonnier Extraction for Measurement of Solids-Not-Fat Content of Raw Milk: Collaborative Study
Authors: Clark Jenny L , Barbano David M , Dunham Chapman E
Published: February 2020

Each of 9 laboratories analyzed 9 pairs of blind duplicate raw milk samples for fat, using the Mojonnier ether extraction method (16.E13-16.E17), and for total solids, using a new direct forced air oven method. Solids-not-fat was determined by subtracting percent fat from percent total solids. The solids-not-fat content of the samples tested in the collaborative study ranged from 8.48 to 9.36%. The average repeatability standard deviation (sr) and the average reproducibility standard deviation (sR) for the solids-not-fat method were 0.019 and 0.041, respectively. Average repeatability (RSDr) and reproducibility (RSDR) relative standard deviations were 0.218 and 0.466%, respectively. The mean repeatability value (r) was 0.055; the mean reproducibility value (R) was 0.117. The difference between milk total solids determined by direct forced air oven drying and milk fat determined by Mojonnier ether extraction has been approved for interim official first action for determination of solids-not-fat content of milk.
Alternative Methods for Infrared Analysis of Fat in Milk: Interlaboratory Study
Authors: Biggs Delmar A , Mckenna David
Published: February 2020

A study in 3 laboratories has demonstrated that accuracy of infrared analysis of fat in milk can be improved relative to results by AOAC method 16.083-16.092 by measuring IR absorption by CH2 and CH3 groups in fat molecules instead of or in addition to measuring absorption by carbonyl groups. Theoretical implications for alternative choices of measurements for fat analysis are discussed, and data are presented to indicate the agreement between theory and practice. Mathematical formulas developed from the Beer-Lambert law are presented to describe mechanisms for dual wavelength, double beam, and single beam optical arrangements. A mathematical description of circuitry for these arrangements is included. Methods for multiple linear regression estimates of calibration parameters are discussed. Comparison data indicate optimum situations regarding frequency of calibration and random selection of calibration samples. With optimum control of calibration parameters, mean bias for randomly chosen check samples was reduced to <0.01%. Standard deviation of difference for fat estimates was reduced to range from 0.026 to 0.034%. Quality control procedures and calibration techniques for individual instruments are described. The use of the Fat B filter and a combination of the Fat A and Fat B filters has been adopted official first action as a revision in method 16.083-16.092.
Modified Liquid Chromatographic Method for Determination of Gentian Violet in Animal Feed
Authors: Martinez Elizabeth E , Shimoda Wilbert
Published: February 2020

A mination of Gentian Violet (GV) in animal feed. The reliable detection limit is 0.5 ng (reference standards), and 1 ppm GV was reliably determined in feed. The calibration curve was linear between 1 and 40 μg/mL. The method, developed in a study by the National Center for Toxicological Research, was modified to use methanol-water (9 + 1) instead of benzene-methanol as the eluting solution in the column cleanup. GV is extracted from feed with methanol-lN HC1 (99 + 1), cleaned up on a Sephadex LH-20 column to remove any remaining interferences, separated on a Nova-Pak C18 column fitted with a precolumn filter, and determined at 588 nm. The identity of GV is confirmed by thin-layer chromatography (R4 = 0.47) by comparison with a reference standard. Average recoveries from 3 sets of 5 feed samples containing 2.5, 5.0, and 10.0 ppm GV were 115, 95, and 102%, respectively.
Development and Validation of New Analytical Method for Acrolein in Air
Authors: Yasuhara Akio , Dennis Jason K , Shibamoto Takayuki
Published: February 2020

A new method was developed to determine vapor-phase acrolein in air samples. Air containing vapor-phase acrolein was purged into impingers filled with a dichloromethane solution of JV-methylhydrazine. The resulting derivative, l-methyl-2-pyrazoline, was analyzed by gas chromatography using a nitrogen-phosphorous detector (NPD). The detection limit was 8.9 pg 1-methyl-2-pyrazoline, equivalent to 5.9 pg acrolein. The recovery efficiencies of vapor-phase acrolein were 98.0 ± 2.9% and 100.3 ± 3.1% for 150 and 15 μg, respectively. This method was satisfactorily applied for determination of acrolein formed from various heated fats. The amounts of acrolein formed in a headspace were 109 μg/L from lard, 164 Mg/L from corn oil, 5.1 μg/L from cotton seed oil, and 163 μg/L from sunflower oil.
Liquid Chromatographic Determination of Epimerization of Chlortetracycline Residue to 4-epi-Chlortetracycline Residue in Animal Feed, Using Mcllvain's Buffer as Extractant
Authors: Martinez Elizabeth E , Shimoda Wilbert
Published: February 2020

A method for studying Mcllvain's solution as a factor in epimerization of chlortetracycline in animal feed has been developed. Mcllvain's solution (McBuffer) was used previously to extract oxytetracycline (OTC), tetracycline-HCl (TC-HC1), and chlortetracycline- HC1 (CTC-HC1) from animal feed because it gave the best recoveries for all 3 tetracyclines; however, the McBuffer solution caused epimerization of CTC-HC1 to 4-epi-chlortetracycline (4-epi-CTC). Recovery results were 30-40% lower for CTC than for OTC and TC from the same sample extract. The levels of concentration tested for CTC and 4-epi-CTC were 10 ppm, the detection limits for both were 3 ppb, and the calibration curves were linear between 5 and 80 ppm for both CTC-HC1 and 4-epi-CTC. The present study shows that CTC recoveries averaged 35% lower because of epimerization initiated by the use of McBuffer in the extraction procedure.
Mechanical Extraction of Available Phosphorus in Fertilizers
Authors: Trimm Joe R
Published: February 2020

A system is described for the extraction of available P205 in fertilizers by mechanically adding water and citrate to a glass cell that contains a ceramic filtering frit. Both water and citrate extractions are performed in the cell. The system can be operated manually or automatically. Samples tested included those from the Magruder and the Association of Florida Phosphate Chemists check sample programs for 1987. For all determinations, the values obtained with the mechanized system were within 1 standard deviation of the average AOAC value reported for each sample.
Effect of Gelatin on Recovery of Hair Fragments in Filth Analysis
Authors: Beavin Bernice B
Published: February 2020

Prior literature has recommended the use of gelatin capsules or gelatin film for transferring spike elements to samples being examined for recovery studies. It was believed that gelatin had no effect on the recovery of filth spike elements. However, this study shows that hair recovery is lower when gelatin is present in direct trap-off procedures. Two types of gelatin capsules, gelatin film, and strips of filter paper were used to transfer spike filth elements. A comparison study employing an acid digestion and wet sieving procedure was also performed and showed that gelatin had little or no effect on the recovery of hairs using this type of procedure. An additional test was performed using gelatin added to water containing the same type of spiked filth elements. No hair fragments were recovered but all insect fragments were recovered. All recovery studies were performed using only water in the liquid phase of the trap flask extractions, with mineral oil or heptane as the flotation medium. No food product was used.
Spectrophotometric Determination of Some Benzene Sulfonamides with 7,7,8,8-Tetracyanoquinodimethane
Authors: Mohamed Abdel-Maboud I
Published: February 2020

A new spectrophotometric method for the determination of some unsubstituted benzene sulfonamides is presented. The method is based on the interaction of these derivatives with 7,7,8,8-tetracyanoquinodimethane at pH 9.0-9.5 to produce intense blue products. The quantitation of the products was carried out at 578 nm. Beer’s law was obeyed over a wide range of concentrations for all sulfonamide compounds studied. Optimum analytical conditions were determined, and the color produced was stable for at least 90 min at 25 °C. Analytical data for determination of sulfonamide compounds in pure form are presented together with application of the proposed method for analysis of some commercially available pharmaceutical preparations. The results are in good agreement with those obtained by official procedures.
Detection of Pork and Lard as Adulterants in Processed Meat: Liquid Chromatographic Analysis of Derivatized Triglycerides
Authors: Saeed Tala , Ali Sadika G , Rahman Hani Abdul A , Sawaya Wajih N
Published: February 2020

A new method is described for detection of pork and lard as adulterants in processed beef and mutton mixtures. The unsaturated triglycerides in the fat are ozonized and then derivatized. The mixture of derivatized and saturated triglycerides is analyzed by liquid chromatography using a reverse-phase column and a UV detector. Pork fat has larger amounts of triglyceride containing saturated fatty acid at the C-2 position than does the fat of other meat. The ratio of triglyceride containing saturated fatty acid vs triglyceride containing unsaturated fatty acid at the same (C-2) position (SSU/SUS) in a sample is compared with those of pure meats. The presence of pork in the sample causes the ratio to increase compared with ratios for pure beef or mutton. The increase in the SSU/SUS ratio is significant for the addition of 1% pork in beef. In the case of mutton, the addition of 3% pork causes a noticeable change. The method is reliable and is also applicable to samples containing only fat. Processing (heating or cooking) does not affect the ratios.
Simplified Extraction and Cleanup for Multiresidue Determination of Pesticides in Lanolin
Authors: Diserens Henri
Published: February 2020

In the proposed method, a light petroleum solution of lanolin (wool fat) is adsorbed on diatomaceous earth in an Extrelut® column, and the pesticides are eluted with acetonitrile saturated with light petroleum. After evaporation to a small volume, the extract is subjected to solid-phase extraction (SPE) on a C-18 column. The acetonitrile eluate is evaporated to dryness and the residue is taken up in light petroleum. Organophosphorus pesticides are determined by temperature- programmed gas chromatography (GC) on a wide-bore column using a flame photometric detector in the phosphorus mode. Organochlorine pesticides are determined after miniaturized Florisil cleanup by classic GC on an OV-17/QF-1 packed column, using an electron capture detector. This procedure is more rapid and straightforward than the time-consuming AOAC extraction method, 29.014. Cleanup was better and the results obtained were comparable. Recoveries for 13 organochlorine and organophosphorus pesticides, frequently found in lanolin, ranged from 80 to 90%
Determination of Organic Arsenicals in Pesticide Formulations by Ion Chromatography
Authors: Gehrig Connie C , Fitzpatrick Timothy M
Published: February 2020

The organic arsenicals, cacodylic acid and methanearsonic acid and their salts, are determined in pesticide formulations by ion chromatography. The samples are diluted in the aqueous mobile phase, injected directly into the chromatograph, and determined by nonsuppressed ion chromatography. Analysis time is less than 5 min for each arsenical. The method was tested for precision, linearity, and recovery. Linearity of the methanearsonic acid gave regression and correlation coefficients of 0.9998 and 0.9999, respectively, and 0.9997 and 0.9998 for cacodylic acid. Quadruplicate analyses of 5 methanearsonic acid samples gave relative standard deviations of 0.833-3.10. Quadruplicate analyses of 4 cacodylic acid samples gave relative standard deviations of 0.648-1.41. Recovery was 100.3 ± 3.6%.
Methodology for the Analysis of Benzimidazole Anthelmintics as Drug Residues in Animal Tissues
Authors: Barker Steven A , Mcdowell Tamera , Charkhian Bahram , Hsieh Lily C , Short Charles R
Published: February 2020

Methodology for the analysis of 8 benzimldazoles as residues in bovine liver is reported. Spiked tissues were extracted by homogenlzation in saline and ammonium hydroxide and blending with diatomaceous earth. This matrix was packed Into a column, and the benzimldazoles were eluted with ethyl acetate. After the sample was further purified, benzimldazoles were separated and quantitated by liquid chromatography with ultraviolet detection (290 nm). Liver tissue samples obtained from cattle which had undergone a drug depletion study of fenbendazole administered per os were analyzed using these methods. The results of these analyses and the application of this approach to multiresidue analysis of drugs in animal tissues are discussed.
Colorimetric Determination of Hydroxyproline as Measure of Collagen Content in Meat and Meat Products: NMKL Collaborative Study
Authors: Kolar Kurt
Published: February 2020

A colorimetric method for the determination of hydroxyproline as a measure of collagen in meat and meat products has been collaboratively studied in 18 laboratories. The method includes hydrolysis with sulfuric acid, oxidation with chloramine- T, and formation of a reddish purple complex with 4- dimethylaminobenzaldehyde. Five frozen and 3 freeze-dried samples were tested, ranging in content from 0.11 to 0.88% and from 0.39 to 4.0% hydroxyproline, respectively. The mean values of 2 identical samples were 0.245 and 0.251 %. The average recovery from a spiked sample was 96.1 %. The hydroxyproline content of a known sample (a mixture of 2 samples in the ratio 5:2) was calculated to 1.42%, which agrees well with the analytical result, 1.40%. In comparison with other collaborative studies, based on the ISO analytical method, the repeatability and reproducibility of this method agree well with the other results. This method was accepted as an official NMKL method by all national Committees, and has been adopted official first action by AOAC as an NMKLAOAC method.
Outlier Detection in Collaborative Studies
Authors: Kelly Patrick C
Published: February 2020

Extended tables of critical values for the reduction In standard deviation tests for single and paired outliers recommended for collaborative studies are presented. Critical values for the single outlier test are derived mathematically and those for the paired test are derived from computer simulations. The single outlier test becomes more and more stringent as the size of the study increases. A confidence Interval approach Is suggested as a means to treat all sizes of collaborative studies in a uniform manner.
Determination of Zearalenone and Related Metabolites in Porcine Urine by Modified Enzyme-Linked Immunosorbent Assay
Authors: Macdougald Ormond A , Thulin Andrew J , Pestka James J
Published: February 2020

A direct competitive enzyme-linked immunosorbent assay (ELISA) was modified for the determination of zearalenone and zearalenols in porcine urine. In the modified procedure, standard or unknown concentrations of zearalenone were added to all wells, followed by rapid addition of zearalenonehorseradlsh peroxidase conjugate, whereas in previous methods, zearalenone and zearalenone-horseradish peroxidase were mixed and then added to microtiter wells. The modification increased the number of urine samples that could be analyzed per assay. The linear portion of the modified ELISA standard curve covered the range of 10-500 ng zearalenone/mL. Average recovery of zearalenone from spiked urine was 91,101,95,107,136,112, and 120% for 1, 10, 25, 50, 100, 250, and 500 ng zearalenone/mL urine, respectively. Mean within-assay coefficient of variation for each concentration of zearalenone in 5 standard curves was 5.95%. Between-assay coefficients of variation for concentrations of zearalenone equivalents in lower and upper regions of the standard curve were 10.9% (n = 18) and 8.8% (n = 20), respectively. Analysis of urine samples showed that a gilt excreted 5.3% of ingested zearalenone in the 8 h following ingestion, with an average excretion rate of about 100 /ug zearalenone equivalents/h.
Effects of Injection Solvent and Mobile Phase on Efficiency in Reverse-Phase Liquid Chromatographic Determination of Aflatoxin M1
Authors: Beaver Rodney W
Published: February 2020

The effects of Injection solvent and mobile phase composition on the reverse-phase liquid chromatographic determination of aflatoxin M1 (M1) were examined. M1 was converted to the more highly fluorescent derivative aflatoxin M2a (M2a)- Using a C-18 column and a mobile phase of H20-MeCNMeOH (60 + 20 + 20) (MP-A), M2a was dissolved in various ratios of MeCN-H20 prior to Injection. Chromatographic efficiency for the M2a peak varied from ca 2000 theoretical plates when injected in 30% aqueous MeCN to ca 9000 plates when injected in water alone. However, using the same C-18 column but with a mobile phase of H20-IPAMeCN (80 + 12 + 8) (MP-B), the M2a peak exhibited 25000 plates when injected in 30% aqueous MeCN and 10000 plates when injected in water alone.
Studies in Adapting the Modified Comprehensive Method for Fertilizer Nitrogen to Block Digestion/Steam Distillation
Authors: Kane Peter , Fitzpatrick Tim
Published: February 2020

A high temperature heating block has been successfully used as an alternative apparatus to traditional Kjeldahl digestion for methods involving various organic nitrogen samples. But the block has not been successfully used for a fertilizer nitrogen methodology. This paper describes an attempt to adapt the AOAC modified comprehensive method for fertilizer nitrogen to the block, followed by steam distillation and titration. A wide variety of reduction conditions were found satisfactory to reduce the N03- nitrogen from KN03. More rigorous digestion parameters, a 450°C block temperature, higher than normal salt/acid ratios, and air condensers to contain the digestion acid were found necessary to achieve full nitrogen recovery from lysine*HCI. The remaining hindrance to a successful fertilizer nitrogen block methodology is that a chromium NH4 + complex found in the digests requires about 30 min to be broken down during the steam distillation step. This is not practical for routine analysis.
Diastatic Activity of Forage Additive Products Containing Malt Flour
Authors: Alli Inteaz , Dilollo Antonio , Kermasha Selim , Thiffault Christine , Dumais Francean
Published: February 2020

A method has been developed for the measurement of diastatic activity of forage additive products which contain malt flour as active ingredient. The procedure Involves extraction of the enzyme activity with calcium chloride solution, Incubation of the extract with excess soluble starch, and measurement of the unhydrolyzed starch by the starch-iodine reaction. The conditions established for optimum enzyme activity were 1 % calcium chloride solution for enzyme extraction, and enzyme-starch reaction pH and temperature of pH 5.5 and 40 °C, respectively. With the combination of these experimental conditions, the diastatic activity, expressed as g starch hydrolyzed per g material per h (SKB) (a) of malt diastase was 75.9 SKB units, (b) of malt flour was 32.8 SKB units, and (c) of 2 forage additive products were 0.205 SKB unit and 0.044 SKB unit.
Diagnostic Data Evaluation. Part I. Collaborative Studies: How To Do It
Authors: Malanoski Anthony J
Published: February 2020

A generic protocol is described to add diagnostic data evaluation to collaborative study evaluations. The protocol would enable the individual performing the evaluation to determine more specifically the causes for unsuccessful studies. The protocol also formalizes the techniques for establishing performance standards for both the analysts and the method.
Colorimetric Deoxyribonucleic Acid Hybridization Assay for Rapid Screening of Salmonella in Foods: Collaborative Study
Authors: Curiale Michael S , Klatt Mary Joan , Mozola Mark A
Published: February 2020

A collaborative study was performed in 11 laboratories to validate a colorimetric DNA hybridization (DNAH) method for rapid detection of Salmonella in foods. The method was compared to the standard culture method for detection of Salmonella in nonfat dry milk, milk chocolate, soy isolate, dried whole egg, ground black pepper, and raw ground turkey. Samples inoculated with high (0.4-2 cells/g) and low (0.04-0.2 cells/g) levels of Salmonella and uninoculated control samples were included in each food group analyzed. There was no significant difference in the proportion of samples positive by DNAH and culture procedure for any of the 6 foods. The colorimetric DNA hybridization assay screening method has been adopted official first action as a rapid screening method for detection of Salmonella in all foods.
Liquid Chromatographic Method for Determination of Aflatoxins B1, B2, G1, and G2 in Corn and Peanut Products: Collaborative Study
Authors: Park Douglas L , Nesheim Stanley , Trucksess Mary W , Stack Michael E , Newell Richard F
Published: February 2020

A collaborative study of a liquid chromatographic method for the determination of aflatoxins B1, B2, G1, and G2 was conducted in laboratories located in the United States, Canada, South Africa, and Switzerland. Twenty-one artificially contaminated raw peanuts, peanut butter, and corn samples containing varying amounts of aflatoxins B1, B2, G1, and G2 were distributed to participating laboratories. The test portion was extracted with methanol-0.1N HCl ( 4 + 1 ) , filtered, defatted with hexane, and then partitioned with methylene chloride. The concentrated extract was passed through a silica gel column. Aflatoxins B1 and G1 were derivatized with trifluoroacetic acid, and the individual aflatoxins were determined by reverse-phase liquid chromatography with fluorescence detection. Statistical analysis of the data was performed to determine or confirm outliers, and to compute repeatability and reproducibility of the method. For corn, relative standard deviations for repeatability (RSDr) for anatoxin B1 ranged from 27.2 to 8.3% for contamination levels from 5 through 50 ng/g. For raw peanuts and peanut butter, RSDr values for aflatoxin Bi were 35.0 to 41.2% and 11.2 to 19.1 %, respectively, for contamination levels from 5 through 25 ng/g. RSDr values for aflatoxins B2, G1, and G2 were similar. Relative standard deviations for reproducibility (RSDR) for aflatoxin B1 ranged from 15.8 to 38.4%, 24.4 to 33.4%, and 43.9 to 54.0% for corn, peanut butter, and raw peanuts, respectively. The method has been adopted official first action for the determination of aflatoxins B1, B2, G1, and G2 in peanut butter and corn at concentrations ≥13 ng total aflatoxlns/g.
Liquid Chromatographic Determination of 5-(Methylamino)-2-Phenyl-4-[3-(Trifluoromethyl)phenyl]-3-(2H)-Furanone in Soil
Authors: Mueller Thomas C , Banks Philip A , Bush Parshall B , Steen William C
Published: February 2020

A rapid, sensitive method is described for the determination of5-(methylamlno)-2-phenyl-4-[3-(trlfluoromethyl)phenyl]-3- (2M)-furanone (RE-40885) concentrations in 3 soil types. The method consists of extraction of soil samples with methanol, filtration, liquid chromatographic separation of methanolsoluble components using a C18 column, and UV detection at 275 nm. Recoveries were 94, 96, and 94% from the Greenville, Cecil, and Dothan soils, respectively. Average relative standard deviation was 8.0% in the Greenville soil. The qualitative limit of detection was 20 ppb and the limit of quantitation was 40 ppb in 25 g soil samples.
Liquid Chromatographic Approaches to Antibiotic Residue Analysis
Authors: Moats William A
Published: February 2020

Liquid chromatography has been widely used for determination of antibiotics and other drugs In formulations and in biological fluids for clinical tests. Application to residue analysis is more difficult because of the need for higher sensitivity and isolation from complex biological substrates. Numerous LC methods for chloramphenicol and sulfonamides have been described. LC methods are beginning to be described for residues of other antibiotics. Several approaches have been used for extraction of residues from food substrates. Residues have been cleaned up and concentrated by using partitioning and/or solid-phase extraction. With some residues, cleanup and analysis can be done In the LC system. LC offers considerable potential for rapid, automated residue analysis.
Survey of Lead and Cadmium in Adult Canned Foods Eaten by Young Children
Authors: Capar Stephen G
Published: February 2020

A U.S. Food and Drug Administration survey of lead and cadmium in 10 adult canned foods commonly eaten by children less than 5 years old was conducted between October 1981 and September 1985. The survey, which Included foods preserved by a commercial canning process and packaged in metal containers, found the highest mean levels of lead (0.32 μg/g) In tuna and of cadmium (0.02 /μg/g) In tuna and tomatoes. Lead levels In foods packaged in lead-soldered cans were about 5 times as high as those In foods packaged in nonlead-soldered cans. Mean lead levels appeared to decline over the 4 years of the study. Cadmium levels were usually below the data reporting limit (0.01 μg/g).
Karl Fischer Determination of Moisture in Soft-Moist Pet Foods: Collaborative Study
Authors: Schulze Roy E
Published: February 2020

Twelve collaborators participated in a study of a Karl Fischer method for determination of moisture in soft-moist, commercially available pet foods. The method avoids the erroneous high results noted In other methods (vacuum drying, toluene distillation, and drying at 135°C) when volatile components other than moisture, such as propylene glycol, are present. The standard deviations for repeatability (sr) and reproducibility (sR) were 0.3 and 0.4, respectively. The corresponding relative standard deviations (RSDr and RSDR) were 1.1 and 1.7%, respectively. The method has been approved interim official first action by AOAC.
Ion-Exchange Liquid Chromatographic Determination of Nitrate and Nitrite in Biological Fluids
Authors: Lippsmeyer Brian C , Tracy Mark L , MÖLLER Gregory
Published: February 2020

A rapid, ion-exchange liquid chromatographic method for the determination of nitrate and nitrite In biological fluids is presented. Samples are deprotelnated by ultrafiltration followed by removal of chloride using a silver form cationexchange resin. Nitrate and nitrite are measured by Ionexchange liquid chromatography with conductivity detection. Recoveries from serum, ocular fluid, and water were determined for fortifications from 10 to 150 mg/L. Average recoveries ranged from 96 to 104% for nitrate and from 89 to 105% for nitrite. Pooled RSD values ranged between 1.5 and 1.9% for these analytes In all matrixes examined. The method of Joint confidence hexagons was applied to the data to determine constant and relative bias of the method for each of the 3 matrixes in the study
Liquid Chromatographic Determination of Total Niacin in Beef, Semolina, and Cottage Cheese
Authors: Tyler Theodore A , Genzale Judith A
Published: February 2020

A sensitive and precise liquid chromatographic method has been developed for the determination of total niacin in beef, semolina, and cottage cheese. The samples are extracted with Ca(OH)2, cleaned up using C18 Sep-Pak cartridges, and chromatographed on a C18 column using a mobile phase consisting of 23% acetonltrlle, 0.10% H3P04, and 0.10% sodium dodecyl sulfate In water. Niacin is detected using an absorbance detector operating at 254 nm. This chromatographic system produces an unusually sharp peak for niacin, enabling a detection limit of approximately 0.05 mg/100 g. The mean recovery was 99.5 % and the coefficients of variation for beef, semolina, and cottage cheese were 3.58,1.02, and 10.0%, respectively
Use of Detergents in the Analysis of Fibrous Feeds. I. Preparation of Fiber Residues of Low Nitrogen Content
Authors: Soest P J Van
Published: February 2020

Anionic, cationic, and nonionic detergents in different buffering media were examined for their capacity to dissolve nitrogenous constituents in forage dry matter, in the interest of preparing fiber of a low nitrogen content. Of the combinations examined, cetyl trimethyl ammonium bromide in strongly acid solution and sodium lauryl sulfate in slightly alkaline solutions appeared most effective.
Organochlorine Pesticide Residues in Different Indian Cereals, Pulses, Spices, Vegetables, Fruits, Milk, Butter, Deshi Ghee, and Edible Oils
Authors: Kaphalia Bhupendra S , Takroo Renu , Mehrotra Suman , Nigam Usha , Seth Tejeshwar D
Published: February 2020

A total of 244 samples of cereals (wheat flour, rice, and maize), pulses (arhar, moong, gram, lentil, and black gram), spices (turmeric, chili, coriander, and black pepper), vegetables (potato, onion, spinach, cabbage, brinjal, and tomato), fruits (mango, guava, apple, and grape), milk, butter, DeshI ghee, and edible oils (vegetable, mustard, groundnut, and sesame) collected from different cities of Northern Province (Utter Pradesh) were analyzed by gas liquid chromatography for the presence of organochlorine pesticide residues. Residues of hexachlorocyclohexane (HCH) and 2,2-bls(p-chlorophenyl)- 1,1,1-trlchloroethane (DDT) were detected In about 85% of the total samples of cereals, spices, milk, butter, DeshI ghee, and edible oils analyzed in the present study. However, the residue levels were either very small (<0.06 ppm) or not detected at all In pulses, vegetables, and fruits as compared with very high concentrations In wheat flour (4.42 and 0.12 ppm), butter (1.19 and 4.85 ppm), mustard oil (1.26 and 2.42 ppm), DeshI ghee (1.10 and 3.84 ppm), vegetable oil (1.02 and 0.59 ppm), groundnut oil (0.51 and 1.49 ppm), and chili (0.48 and 1.92 ppm). The levels of HCH and DDT residues detected in rice, maize, turmeric, coriander, black pepper, and all the vegetables and fruits were also lower than those found In wheat flour, oil, and fat samples analyzed In the present study. These findings suggest that a restricted and controlled use of such persistent pesticides may be useful for decreasing their contamination levels In different food Items.
Spectrophotometric Determination of Some Catecholamine Drugs Using Metaperiodate
Authors: El-Kommos Michael E , Mohamed Fardos A , Khedr Ala'a S
Published: February 2020

A rapid spectrophotometric procedure for the determination of Isoprenaline salts, levodopa, dopamine hydrochloride, and dobutamine hydrochloride, either In the drug substances or In pharmaceutical formulations, Is described. The method is based on the development of orange, red, or violet products with sodium metaperiodate in an aqueous alcoholic medium. The reaction is suggested to proceed via oxidative cyclizatlon of the catecholamine to form an amlnochrome. The wavelengths of maximum absorption range from 465 to 520 nm. The structure of the cyclization product was confirmed by ultraviolet, infrared, and nuclear magnetic resonance spectroscopy and microanalysis data.
Spectrofluorometric Determination of Histamine in Fish and Meat Products
Authors: Vidal-Carou María Del Carmen , Veciana-Nogués María Teresa , Mariné-Font Abel
Published: February 2020

A method has been developed for spectrofluorometric determination of histamine in fish and meat products. After a perchloric extract Is obtained from samples, histamine Is extracted with n-butanol and transferred to hydrochloric acid. Finally, histamine Is subjected to a condensation reaction with o-phthalaldehyde (OPT). The method was tested for lack of interference from other amines. Precision of the method In fish products was 6.60% CV; recovery was 96.50%. In meat products, precision was 5.42% CV; recovery was 96.20%. By analysis of variance (P = 0.05), no significant statistical differences were found for recovery values vs histamine content In both foods.
Liquid Chromatographic Method for Determination of Cyfluthrin in Technical and Formulated Products
Authors: Slahck Stephen C
Published: February 2020

A liquid chromatographic method for determination of cyfluthrin (Baythrold®, Tempo®) diastereomers In technical and formulated products has been developed. Samples are dissolved in dloxane-hexane and analyzed by normal-phase liquid chromatography using acetophenone as an internal standard. The method Is applicable to technical Baythrold, Baythrold 2 EC, Tempo 20 WP, and granular formulations. The method separates all 4 diastereomers of cyfluthrin and all impurities in less than 19 mln.
Liquid Chromatographic Determination of Acifluorfen in Soil and Water
Authors: Gennari Mara , Negre Michèle , Cignetti Alessandro
Published: February 2020

An analytical method based on the use of a liquid chromatograph equipped with a UV detector was developed for the determination of acifluorfen In soil and water. Acifluorfen was extracted from soil In methanol-0.10N NaOH (80 + 20 v/ v) and from water by partition with dlchloromethane. Solvent partitioning and solid-phase extraction were used to separate acifluorfen from major Interfering sample components. Average recoveries from soil at 1, 0.1, and 0.01 ppm fortification levels were 95.1 ± 3.4,92.6 ± 2.9, and 73.9 ± 3.0%, respectively. Recoveries from water spiked at levels from 0.01 to 1 ppm averaged 96.5 ± 5.4%. Method limits of detection were 0.006 ppm in soil and 0.003 ppm In water.
Flame Atomic Absorption Spectrometric Determination of Serum Zinc: Collaborative Study
Authors: Perry Dana F
Published: February 2020

A method for determining serum zinc concentrations was collaboratively studied by 9 laboratories. Serum samples In polypropylene tubes are directly diluted with 0.03% Brij 35, and zinc is determined by flame atomic absorption spectrophotometry (AAS). A certified standard reference material serves as an external control. Repeatability relative standard deviations (RSDr) were 1.2 and 11.4% and reproducibility relative standard deviations (RSDR) were 6.1 and 12.9% for serum zinc concentrations of 6.36 and 0.63 μg/mL, respectively. The method has been approved Interim official first action by AOAC.
Precision Parameters of Methods of Analysis Required for Nutrition Labeling. Part I. Major Nutrients
Authors: Horwitz William , Albert Richard , Deutsch Mike J , Thompson Neville J
Published: February 2020

Major components of foods and feeds are fat, protein, and carbohydrates. Fat and protein are determined by direct measurements that are Interpreted as the quantity of the constituent. Carbohydrates are usually calculated by difference. For this calculation, values for molsture/sollds, ash, and "fiber" are also needed. The readily available collaborative studies for the determination of these major components are reviewed In an attempt to assign precision parameters to validated methods of analysis. When a number of studies for the same analyte, In the same food, by the same method are available, It Is seen that the precision parameters among laboratories (standard deviations, SR; relative standard deviations, RSDR) and the ISO maximum tolerable difference functions (repeatability value, r; reproducibility value, R) are not characterized by any conventional distribution. The precision data are best summarized as a median or average parameter and the Interval containing the centermost 90% of reported values. Typically, the precision of methods of analysis can be expressed as a function of concentration only, independent of analyte, matrix, and method. The average RSDR value from each collaborative data set can then be used as the numerator In a ratio containing, as the denominator, the value calculated from the Horwitz equation: RSDR = 2 exp (1 — 0.5 log C) where C Is the concentration as a decimal fraction. A series of ratios consistently above 1, and especially above 2, probably Indicates that a method Is unacceptable with respect to precision. By this criterion, only the protein (KJeldahl) determination Is unqualifiedly acceptable with a 90% interval for RSDR of 1 to 3% at C values above about 0.01 (1 g/100 g). Fat, moisture/solids, and ash are acceptable down to limiting concentrations In the region of 1 to 5 g/100 g, If a test portion large enough to provide at least 50 mg of welghable residue or volatlles Is specified. Measurements of Individual carbohydrates and fiber-related analytes have unexpectedly poor precisions among laboratories. The variability, although high, may still be suitable for nutrition labeling. Reliability of analyses for the control of labeling of the primary nutrients must be achieved through quality assurance programs that require strict adherence to the directions of empirical methods and the use of suitable reference materials for absolute methods.
Evaluation of APHA and AOACII Methods for Phosphatase in Butter and Differentiation of Milk and Microbial Phosphatases by Agarose-Gel Electrophoresis*
Authors: Murthy Gopala K , Kaylor Lawrence O
Published: February 2020

Salted and unsalted butters with 3 levels of phosphatase were prepared with both raw and pasteurized cream containing 36% fat. Test samples were analyzed for phosphatase by the modified method of the American Public Health Association (APHA) and the official AOAC method, 16.256 (1984, 14th Ed., 1990 15th Ed., 946.02). In the APHA method, weighing of solid frozen butter for testing yielded repeatable results. Addition of 0.0-1.0 mg magnesium to the butter had little effect on phosphatase activity In the APHA modified rapid colorlmetrlc method (MRCM), but caused the phosphatase activity to decrease In the AOAC method. Phosphatase In salted and unsalted butters was quite stable at —17 ± 1°C and at 3.0 ± 0.5°C; however, within 2 to 4 days, freshly prepared butters stored at 22 ± 1°C developed reactivated and/or microbial phosphatases that were both heat-labile and heat-stable. At 22 ± 1°C, frozen butters showed decreased milk phosphatase activity before producing microbial phosphatase. Heat-labile phosphatases in salted and unsalted butters were Inactivated at 62.8 °C for 10 mln, and the phosphatase lability was partially due to the heat-denaturing effect of NaCI In salted butter. Some heat-stable phosphatases In unsalted butter survived at 66°C for 30 mln. Differentiation of milk phosphatase from microbial phosphatases was difficult by both methods; however, they were successfully differentiated by the agarose-gel electrophoretlc technique.
Dry Calibration Milks for Infrared Milk Analyzers
Authors: Van De Voort Frederick R. , Elkashef Abdel A , Mills Bernice L
Published: February 2020

A study has been carried out to determine the practicality of formulating dry, stable calibration milk powders for calibration of infrared milk analyzers for routine quality control purposes in commercial dairies. The powders are based on dairy Ingredients and are reconstituted to produce calibration milks that cover a wide range of fat, protein, and lactose composition combinations. The butterfat component included emulsifiers to aid in reconstituting the powders and to stabilize resulting emulsions. Reconstitute was carried out on a weight/weight basis using a top-loading balance and mixing with a simple hand-held, electric household mixer. The reconstitutlon procedure produced stable emulsions and was shown to be repeatable to within the accuracy specifications of Infrared instrumentation. The calibration results obtained with the powders relative to reference calibration milks purchased from the Central Milk Testing Laboratory (CMTL) In Guelph, Ontario, were excellent, and generally met AOAC specifications for Instrument calibration. In addition, the reconstituted milks had excellent emulsion stability to prolonged holding at 40°C and produced consistent results when analyzed over a 21-day period, showing no signs of spoilage when preserved with potassium dlchromate and refrigerated when not In use. The powders were deemed adequate for calibration of Infrared milk analyzers used for routine, In-plant, quality control purposes and would be a convenient alternative for CMTL calibration milks shipped by courier.
Liquid Chromatographic Determination of Pentaerythritol Tetranitrate in Pharmaceuticals: Collaborative Study
Authors: Carlson Marvin
Published: February 2020

A liquid chromatographic (LC) method for the determination of pentaerythritol tetranitrate (PETN) In pharmaceutical formulations and the bulk drug triturate was evaluated in an Interlaboratory study that Included 12 participating laboratories. The procedure Involves extraction of the active ingredient with mobile phase, followed by filtration of the extract and reverse-phase liquid chromatography using an octadecylsllane bonded phase column and UV detection at 230 nm. The mobile phase composition Is 35% water In acetonltrlle (v/v). Three bulk drug samples (20, 20, and 35% PETN), 2 commercial tablet formulations (20 and 80 mg PETN/tablet), and 1 commercial capsule formulation (45 mg PETN/capsule) were analyzed In duplicate by the proposed method. Repeatability (sr, RSDr) and reproducibility (sR, RSDR) based on peak height measurement for these samples ranged from 0.0066 to 0.1806 (0.53-3.36%) and 0.0165 to 0.2075 (0.76- 3.86%), respectively. Results for peak area measurements ranged from 0.0145 to 0.2011 (0.93-3.74%) and 0.0231 to 0.2091 (1.28-3.89%), respectively. The method has been approved Interim official first action by AOAC.
Gas Chromatographic Method for Determination of p,p'-DDT in DDT Technical and Formulated Products: Collaborative Study
Authors: Mount Dwight L , Churchill Frederick C
Published: February 2020

A gas chromatographic (GC) method for determination of p,//-DDT In technical and formulated products was developed and It performed well in an initial small collaborative study among 4 laboratories. Samples are dissolved in chloroform, and p,p'-DDT is separated on an OV-210 column and determined by GC analysis with flame Ionization detection. 2,2'-Dlnltroblphenyl Is used as an Internal standard. The method was subjected to an International collaborative study with 10 participating laboratories. Collaborators received matched pairs of technical DDT products and of water-dlsperslble powder, emulslflable concentrate, and dustable powder formulations. Relative standard deviations for reproducibility (RSDR) for the paired samples were 1.16, 1.48, 2.08, and 1.80%, respectively. The method has been approved Interim official first action by AOAC as a CIPACAOAC method.