Search

Deoxynivalenol (DON), commonly referred to as vomitoxin, belongs to a class of naturally occurring mycotoxins produced by Fusarium fungi. The presence of DON in foods is a human health concern. The frequency of occurrence of DON in wheat is high, although cleaning prior to milling can reduce DON concentration in final products, and food processing can partially degrade the toxin. This paper describes a method for the determination of DON in some major wheat food products, including bread, breakfast cereals, pasta, pretzels, and crackers. Test samples containing 5 polyethylene glycol were extracted with water. After blending and centrifuging, the supernatant was diluted with water and filtered through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column and the toxins eluted with methanol. The toxins were then subjected to RPLC separation and UV detection. The accuracy and repeatability characteristics of the method were determined. Recoveries of DON spiked at levels from 0.5 to 1.5 g/g in the five processed foods were >70. SD and RSD values ranged from 2.0 to 23.5 and from 2.0 to 23.2, respectively. HorRat values were

AOAC Official MethodSM 991.31 for the determination of aflatoxins (AFs; sum of aflatoxins B1, B2, G1, and G2) in corn, raw peanuts, and peanut butter by using immunoaffinity column cleanup with LC has been modified and applied to the determination of AFs in botanical roots. The modifications were necessary to improve the performance of the method for matrixes beyond corn and peanuts. The extraction solvent was changed from a mixture of methanol and water to acetonitrile and water. The accuracy, repeatability, and reproducibility characteristics of this method were determined. Replicates of 10 test portions of each powdered root (black cohosh, echinacea, ginger, ginseng, kava kava, and valerian) at each spiking level (AFs at 0, 2, 4, 8, and 16 ng/g) were analyzed on 3 separate days. Test portions were extracted with acetonitrilewater (84 + 16, v/v), and the extracts were centrifuged, diluted with phosphate-buffered saline, filtered, and applied to an immunoaffinity column containing antibodies specific for AFs. After the column was washed with water, the toxins were eluted from the column with methanol and quantified by HPLC with fluorescence detection. All test materials except kava kava were found to contain AF at

Botanical products are in great demand in health food markets. Botanicals are used for treatment of diseases as well as to promote health (1). Raw materials for medicinal use and herbal supplements frequently are contaminated with toxigenic fungi originating in the soil; the plants themselves are susceptible to fungal growth both pre- and post-havest under the right environmental conditions (2). Contamination with mycotoxins produced by these fungi could pose human health problems. In recent years, many incidences of natural occurrence of mycotoxins in botanicals have been reported (3). Aflatoxins (AF), the naturally occurring aflatoxins B1, B2, G1, and G2 (AFB1, AFB2, AFG1, AFG2), and ochratoxin A (OTA) have been found in ginseng, ginger, licorice, turmeric, and kava-kava in the United States (4, 5). Fumonisins have been found in medicinal wild plants in South Africa (6) and medicinal plants in Turkey (7) and Portugal (8). Zearalenone was identified in ginseng root (9). The presence of AF and OTA in botanicals may pose risks to human health. AF and OTA were found to co-occur in ginger (5). A multitoxin method for the determination of AF and OTA in botanical roots is needed. A method that is capable of determining AF and OTA simultaneously in powdered ginger and ginseng had been developed (5). The method uses a single immunoaffinity column for cleanup, high-performance liquid chromatography (LC) with post-column derivatization for AF fluorescence enhancement, and fluorescence determination for the toxins. The purpose of this collaborative study was to establish the accuracy, repeatability, and reproducibility parameters of the method by the analysis of spiked powdered ginseng and ginger and naturally contaminated powdered ginger.

Mycotoxins are toxic secondary metabolites produced by certain molds and are common contaminants of many important food crops, such as grains, nuts, and spices. Some mycotoxins are found in fruits, vegetables, and botanical roots. These contaminants have a broad range of toxic effects, including carcinogenicity, immunotoxicity, neurotoxicity, and reproductive and developmental toxicity. The public health concerns related to both acute and chronic effects of mycotoxins in animals have prompted more than 100 countries to establish regulatory limits for some of the well-known mycotoxins, such as the aflatoxins (AFL). Our research focused on method development for 2 of these toxins, AFL and ochratoxin A (OTA), in ginseng and other selected botanical roots. Methods using an immunoaffinity column (IAC) cleanup, liquid chromatographic separation, and fluorescence detection were modified and evaluated. Two types of IAC cleanup were evaluated: IAC for AFL, and IAC for both AFL and OTA. Three derivatization techniques to enhance the fluorescence of the AFL were compared: precolumn trifluoroacetic acid, postcolumn bromination, and postcolumn ultraviolet irradiation. No derivatization was needed for OTA. Results for AFL using the single analyte IAC cleanup and the 3 derivatization techniques were all comparable for ginseng and for other roots such as ginger, licorice, and kava-kava. Recoveries of added AFL for ginseng at levels from 2 to 16 ng/g were about 80%. Using IAC cleanup for both AFL and OTA recoveries of added AFL for ginseng at 416 ng/g were about 70%, and for ginger, licorice, and kava-kava were about 60%. Recoveries of added OTA for ginseng, ginger, and echinacea at 4 ng/g were about 55%.

AOAC Official Method 999.14 is applicable for the determination of choline in milk and infant formulas. To date, its use has not been extended beyond these matrixes. We modified Official Method 999.14 and applied it to the determination of choline in a range of choline-containing dietary supplements. Dietary supplement tablets, capsules, wafers, softgels, liquid products, and drink powders were included. We found that the standard curve could be extended to cover a wider range of choline concentrations and defined a procedure for the use of Norit for samples in which the vitamin C content was high enough to interfere with the analysis. Recoveries of choline added to infant formula powders and to representative dietary supplement tablets, capsules, powdered drink mix, and wafer products were 85-114%. The use of Norit during the procedure did not affect the recovery of choline added to infant formula powders or to dietary supplements. An alkaline digestion was included for use with a product containing lecithin as the sole source of choline. Ten of 11 dietary supplement products analyzed by the modified method contained amounts of choline at or above declarations found on the product labels. The remaining product contained about 40% of the label-declared amount of choline.

The full compliance date for mandatory folic acid fortification of enriched cereal-grain products in the United States was 1 January, 1998. There is currently a great interest in determining the effectiveness of this measure, which was instituted to increase the folate intakes of women of child-bearing age to reduce their risk of having a pregnancy affected by a neural tube birth defect. We surveyed 83 enriched cereal-grain products that are required to be fortified with folic acid under the new regulations and an additional 79 foods that contain enriched cereal-grain ingredients or that are currently fortified with folic acid. Products were collected and analyzed between February 1998 and April 1999. Total folate was determined by microbiological assay using a tri-enzyme digestion. We compared analyzed values for total folate with amounts required by Federal regulations and/or with label declarations of folate content. For many enriched cereal-grain products, there were significant differences between amounts of folate found on analysis and amounts required by Federal regulations. In part because of this, label declarations of folate content were also in error. The high values found in some enriched cereal-grain products may represent manufacturers' averages as well as the presence of higher-than-expected levels of endogenous folates. These results indicate that reliable food composition databases cannot be developed without extensive new data on the actual concentrations of folate in recently fortified enriched cereal-grain products as well as in products containing enriched cereal-grain ingredients. Reliance on older data bases or on compositional information that has a weak analytical underpinning will lead to unsound estimates of folate intake, and hence, of the potential impact of the new fortification program.

January 1, 1998 was the effective date for PDA regulations that mandated the fortification in the USA of a wide range of enriched cereal-grain products with folic acid at levels specified in federal regulations. Because data on prefortification levels of folate in such products are limited, we measured folate in 56 enriched foods, including enriched breads and rolls, flours, corn grits and meals, rices, and macaroni and noodle products. Folate was measured by a modification of the Association of Official Analytical Chemists' microbiological method 992.05 using Lactobacillus casei . Foods were composited, suspended in 0. 1 m phosphate buffer containing 1% ascorbic acid (pH 7.8), autoclaved and cooled. Chicken pancreas conjugase was added and the suspensions were incubated for 16h at 37 °C. Values for folate in enriched products were (μg/lOOg): bread and rolls, 24–40; flours, 19–24; corn grits and meals, 22–32; macaroni and noodle products, 27–42; rice, 19–32. Because the single-enzyme method is usually insufficient to liberate food-bound folates, suspensions of foods were also incubated with α-amylase and conjugase followed by treatment with protease to determine the effects of the tri-enzyme digestion on release of folates. For many foods, total folate was 20–30% higher after the tri-enzyme digestion than after incubation with conjugase alone. The modifications of AOAC method 992.05 described here provide a microbiological assay method for the determination of folates in cereal-grain products that may be appropriate for collaborative testing.

Consumers' interest in dietary guidelines advising them to reduce their intake of fat has contributed to the development of new low- and fat-free margarine-like products. We measured vitamin E (α-tocopherol) and vitamin A (retinol and /gb-carotene) in margarines and margarine-like products labeled as containing 0–80% fat. Test portions were saponified, extracted with petroleum ether, and analyzed by high performance liquid chromatography. Margarines of approximately 80% fat content contained 4–30 IU /ga-tocopherol/100 g. Reduced-fat margarines (fat content 14–53%) contained 4–15 IU α-tocopherol/100 g, while fat-free margarines (

There is increasing interest in the fatty acid composition, including levels of trans fatty acids, of foods. The trans fatty acid content of American diets is increasingly studied because of reported adverse effects of trans fatty acids on risk of coronary heart disease. In this study, total fat content and fatty acid composition of 43 food products were determined after acid hydrolysis by gas chromatography using an SP-2560 flexible fused silica capillary column. Total fat content determined by the gas chromatographic method was compared with fat content determined by AOAC gravimetric method 922.06 for all food products. Total fat, saturated fat and unsaturated fat content of the foods determined by the gas chromatographic method ranged from 0.9 to 96.7, 0.2 to 16.8 and 0.5 to 89.3%, respectively. Trans fatty acids hexadecenoate (t-16:1), elaidic (t-18:1), and octa-decadienoate (t,t-18:2) were identified by comparison of their retention times with those of known standards and quantitated. These fatty acids were present in foods at levels of 0.25 to 1.50 (t-16:1), 0.87 to 268.32 (t-18:1), and 0.23 to 7.92 (t,t-18:2) mg/g.

The totaltrans fatty acid content of 18 food products was determined, after acid hydrolysis, extraction and methylation of fatty acids, by gas chromatography with a polar 100% cyanopropylsiloxane capillary column and by single-bounce horizontal attenuated total reflection spectroscopy (SB-HATR). Thetrans fatty acid methyl esters (FAME) of 9-hexadecenoate (9t-16:1), 9-octadecenoate (9t-18:1), and 9,12-octadecadienoate (9t,12t-18:2) were identified by comparison of their retention times with those of known standards and quantitated. The isomersc,t- andt,c-18:2 were identified from their published retention times and included in the quantitation oftrans FAME. Neat 50-μL portions of the FAME that were used for gas-chromatographic analysis also were analyzed by SB-HATR. This technique requires neither weighing nor quantitative dilution of test portions prior to spectroscopic quantitation of isolated double bonds oftrans configuration. A symmetric 966-cm−1 absorption band on a horizontal background was obtained from unhydrogenated soybean oil FAME as the reference material. For 9 of 11 products withtrans fat content>5% of total fat, results obtained by SB-HATR were higher than those obtained by gas chromatography. Results obtained by the gaschromatographic procedure were slightly to significantly higher than those obtained by SB-HATR for the six foods in whichtrans fat content was

The new definition of total fat in FDA regulations implementing the Nutrition Labeling and Education Act of 1990 necessitates the quantitation of all lipid fatty acids and the summation of their triglyceride equivalents. A gas-liquid Chromatographic (GLC) method using a packed column has been developed for quantitative measurement of total fat and saturated fat in foods. Fatty acids are released from food matrices by acid hydrolysis, and then extracted, esterified to their methyl esters and determined by GLC. Total fat and saturated fat are calculated in accordance with the new definitions of these components. Fat content determined by the acid hydrolysis-GLC methodology was compared with fat content determined by a direct AOAC gravimetric method for 23 food products containing between about 1 and 75% fat by weight. For all food products studied, the relationship between the results obtained by the two methods was best described by a straight line that had a correlation coefficient of 0.94. Results of repeated extractions and analysis of a milk-based infant formula (SRM 1846) suggest that this material may be useful as a quality control standard.

A microbiological technique was developed for quantitating niacin by determining microbial growth rates in response to the amount of vitamin available. Unlike the current official AOAC method, the new procedure for niacin measured the growth rates during the early exponential growth phase rather than during the stationary phase. Lactobacillus plantarum was used to determine niacin to a lower limit of 100 pg/mL. The assay time was approximately 6 h, compared with 16-24 h for the current AOAC method. The extent of microbial growth was determined by differential light scattering of a LASER beam. Multiple photodetectors were integrated with a computer system to collect and analyze the data. The use of differential light scattering to determine 8 water-soluble vitamins under stationary phase conditions demonstrated the potential application of the new technology for microorganisms and foods.

Deoxynivalenol (DON), commonly referred to as vomitoxin, belongs to a class of naturally occurring mycotoxins produced by Fusarium fungi. The presence of DON in foods is a human health concern. The frequency of occurrence of DON in wheat is high, although cleaning prior to milling can reduce DON concentration in final products, and food processing can partially degrade the toxin. This paper describes a method for the determination of DON in some major wheat food products, including bread, breakfast cereals, pasta, pretzels, and crackers. Test samples containing 5% polyethylene glycol were extracted with water. After blending and centrifuging, the supernatant was diluted with water and filtered through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column and the toxins eluted with methanol. The toxins were then subjected to RPLC separation and UV detection. The accuracy and repeatability characteristics of the method were determined. Recoveries of DON spiked at levels from 0.5 to 1.5 microg/g in the five processed foods were70%. SD and RSD values ranged from 2.0 to 23.5% and from 2.0 to 23.2%, respectively. HorRat values were2 for all of the matrixes examined. The method was found to be acceptable for the matrixes examined. LC/MS/MS with multiple-reaction monitoring was used to confirm the identity of DON in naturally contaminated test samples.

Ginger has been used as a food, dietary supplement, and condiment for centuries. Mycotoxins such as the aflatoxins (AF) and ochratoxin A (OTA) have been reported in ginger roots in several studies. It is important to design effective sampling methods that will accurately and precisely predict the true mycotoxin level in a bulk lot. The objective of this study was to measure the sampling and analytical variability associated with the test procedure used to measure AF and OTA in a bulk lot of powdered ginger using a 5-g laboratory sample and HPLC analytical methods. Twelve 5-g laboratory samples were taken from each of two lots. Duplicate aliquots were removed from each 5-g laboratory sample/solvent blend, and each aliquot was simultaneously analyzed for AF and OTA by HPLC analytical methods. Using a balanced nested design, the total variance associated with the above AF and OTA test procedures was partitioned into sampling and analytical variance components for each lot. Averaged across both lots, the sampling and analytical variances accounted for 87% and 13% of the total variance, respectively, for AF and 97% and 3%, respectively, for OTA. The sampling and analytical coefficients of variation were 9.5% and 3.6%, respectively, for AF, and 16.6% and 2.9%, respectively, for OTA when using a single 5-g laboratory sample and HPLC analytical methods. Equations are derived to show the effect of increasing laboratory sample size and/or number of aliquots on reducing the variability of the test procedures used to estimate OTA and AF in powdered ginger.

The U.S. Food and Drug Administration is studying the need to monitor dietary supplements for mycotoxins such as total aflatoxins and ochratoxin A. An effective mycotoxin-monitoring program requires knowledge of the sampling and analytical variability associated with the determination of total aflatoxins (AF) and ochratoxin A (OTA) in dietary supplements. Three lots of ginger sold as a powder in capsule form and packaged in individual bottles were analyzed for both AF and OTA. The total variability associated with measuring AF and OTA in powdered ginger was partitioned into bottle-to-bottle, within bottle, and analytical variances. The variances were estimated using a nested design. For AF and OTA, the within-bottle variance associated with the 5 g laboratory sample size was the largest component of variability accounting for about 43% and 85% of the total variance, respectively; the analytical variance accounted for about 34% and 9% of the total variability, respectively; and the bottle-to-bottle variance accounted for about 23% and 7% of the total variance, respectively. When the total variance is converted into the coefficient of variation (CV or standard deviation relative to the mean concentration), the CV is lower for AF (16.9%) than OTA (24.7%).

The accuracy, repeatability, and reproducibility characteristics of a method using multitoxin immunoaffinity column cleanup with liquid chromatography (LC) for determination of aflatoxins (AF; sum of aflatoxins B1, B2, G1, and G2) and ochratoxin A (OTA) in powdered ginseng and ginger have been established in a collaborative study involving 13 laboratories from 7 countries. Blind duplicate samples of blank, spiked (AF and OTA added) at levels ranging from 0.25 to 16.0 microg/kg for AF and 0.25 to 8.0 microg/kg for OTA were analyzed. A naturally contaminated powdered ginger sample was also included. Test samples were extracted with methanol and 0.5% aqueous sodium hydrogen carbonate solution (700 + 300, v/v). The extract was centrifuged, diluted with phosphate buffer (PB), filtered, and applied to an immunoaffinity column containing antibodies specific for AF and OTA. After washing the column with water, the toxins were eluted from the column with methanol, and quantified by high-performance LC with fluorescence detection. Average recoveries of AF from ginseng and ginger ranged from 70 to 87% (at spiking levels ranging from 2 to 16 microg/kg), and of OTA, from 86 to 113% (at spiking levels ranging from 1 to 8 microg/kg). Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 2.6 to 8.3% for AF, and from 2.5 to 10.7% for OTA. Relative standard deviations for between-laboratory reproducibility (RSDR) ranged from 5.7 to 28.6% for AF, and from 5.5 to 10.7% for OTA. HorRat values wereor = 2 for the multi-analytes in the 2 matrixes.

As part of the Food Labeling and Product Surveillance Program of the Food and Drug Administration, samples from 1982, 1984, and 1986 surveys of processed packaged foods (canned, frozen, and dry packaged) were analyzed to determine how closely the foods' actual sodium content matched their label claims for sodium. Samples were classified into three groups: "sodium-free" products (less than 5 mg sodium per serving), and "very-low-sodium" products (5 to 35 mg per serving), and a larger group of products that were labeled as containing more than 35 mg sodium per serving. In the third group, the distribution of actual sodium content fell around 100% of label claims for sodium. For the three survey years, analyzed sodium averaged 101% of label claim (standard deviation [SD] = 25%) for 1982 samples (20 products), 99% of label claim (SD = 28%) for 1984 samples (108 products), and 94% of label claim (SD = 21%) for 1986 samples (265 products). Products labeled "very low sodium" were treated separately because sodium analyses varied widely from the label declarations. However, most "very-low-sodium" products were well under 35 mg sodium per serving. Results indicated that consumers receive reasonably accurate information about the sodium content of processed packaged foods from label claims.

Conditions were optimized for the simultaneous, alkaline, aqueous methanol extraction of aflatoxins (AFL), i.e., B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2), and ochratoxin A (OTA) with subsequent purification, isolation, and determination of the toxins in ginseng and ginger. Powdered roots were extracted with methanol-0.5% NaHCO3 solution (7 + 3). After shaking and centrifugation, the supernatant was diluted with 100 mM phosphate buffer containing 1% Tween 20 and filtered through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column, and the toxins were eluted with methanol. The AFL were separated and determined by reversed-phase liquid chromatography (RPLC) with fluorescence detection after postcolumn UV photochemical derivatization. OTA was separated and determined by RPLC with fluorescence detection. Recoveries of AFL added at 2-16 ng/g and OTA added at 1-8 ng/g to ginseng were 72-80 and 86-95%, respectively. Recoveries of AFL and OTA added to ginger were similar to those for ginseng. A total of 39 commercially available ginger products from 6 manufacturers were analyzed. Twenty-six samples were found to be contaminated with AFL at 1-31 ng/g and 29 samples, with OTA at 1-10 ng/g. Ten samples contained no AFL or OTA. Ten ginseng finished products were also analyzed; 3 contained AFL at 0.1 ng/g and 4 contained OTA at levels ranging from 0.4 to 1.8 ng/g. LC/tandem mass spectrometry with multiple-reaction monitoring of 3 collisionally induced product ions from the protonated molecular ions of OTA, AFB1, and AFG1 was used to confirm the identities of the toxins in extracts of the finished products.

Ginseng roots can be infected by molds during growth, harvest and storage and result in contamination with mycotoxins. In this study, an analytical method for the determination of aflatoxins B(1), B(2), G(1) and G(2), a group of structurally similar mycotoxins, in ginseng root was developed. Test samples were extracted with methanol-water (8?+?2), diluted and passed through an immunoaffinity column packed with antibodies specific for aflatoxins. The purified extract was then derivatized with a mixture of water, trifluoroacetic acid and acetic acid. Aflatoxins were then separated and quantified by reverse phase liquid chromatography (LC) with fluorescence detection. Recoveries of total aflatoxins at 2, 4, 8 and 16 ng/g added to toxin-free 4 to 5-year old dried sliced Wisconsin ginseng were 92, 77, 91 and 83% respectively; and relative standard deviations were 3.6, 8.0, 6.9 and 2.0% respectively. A total of 11 wild simulated and 12 cultivated ginseng root samples were analysed for aflatoxins. All cultivated roots were found to be free of aflatoxin contamination. Two of the wild simulated roots contained total aflatoxins B(1), B(2), G(1) and G(2) at 15.1 and 15.2 ng/g. One moldy ginseng root purchased from a grocery store was found to be contaminated with aflatoxins at 16 ng/g.

AOAC Official Method 999.14 is applicable for the determination of choline in milk and infant formulas. To date, its use has not been extended beyond these matrixes. We modified Official Method 999.14 and applied it to the determination of choline in a range of choline-containing dietary supplements. Dietary supplement tablets, capsules, wafers, softgels, liquid products, and drink powders were included. We found that the standard curve could be extended to cover a wider range of choline concentrations and defined a procedure for the use of Norit for samples in which the vitamin C content was high enough to interfere with the analysis. Recoveries of choline added to infant formula powders and to representative dietary supplement tablets, capsules, powdered drink mix, and wafer products were 85-114%. The use of Norit during the procedure did not affect the recovery of choline added to infant formula powders or to dietary supplements. An alkaline digestion was included for use with a product containing lecithin as the sole source of choline. Ten of 11 dietary supplement products analyzed by the modified method contained amounts of choline at or above declarations found on the product labels. The remaining product contained about 40% of the label-declared amount of choline.

There is a need for food based reference materials characterized for organic nutrient content, since very few are presently available. A series of twelve food matrices has been prepared by Agriculture Canada as Candidate Reference Materials. This paper reports a survey of the organic nutrient content of these twelve materials which include bovine muscle powder, corn starch, hard red spring wheat flour, soft winter wheat flour, white granulated sugar, whole milk powder, wheat gluten, potato starch, corn bran, durum wheat flour, whole egg powder, and microcrystalline cellulose. Whole egg, bovine muscle and whole milk powder appear to be best suited for further development as organic nutrient standards.

The retention and distribution of eight polybrominated biphenyl (PBB) congeners were studied by roasting beef sirloin tip samples to an internal temperature of 65 degrees C, braising and broiling adductor and semimembranosus steaks to an internal temperature of 77 degrees C, broiling ground round and hamburger patties 77 degrees C, and comparing cooked values with those in the raw. Rounds were obtained from four Holstein cows with known PBB contamination. Significant reductions in PBBs occurred with cooking of all cuts. Roasting sirloin tips reduced the PBBs by 45.7%. Broiling reduced PBBs as follows: Adductor steaks (53.2%), semimembranosus steaks (71.2%), ground beef patties (32.3%) and hamburger patties (31.5%). Braising reduced PBBs in the adductor steaks by 37.2% and in the semimembranosus steaks by 34.9%. The distribution of PBB congeners was also affected by cooking in all cuts except hamburger. The proportion of 2,4,5,2',4',5'-hexabromobiphenyl decreased upon cooking but the change in the proportion of 2,3,4,5,2',4',5'-hepatbromobiphenyl varied with the cut used. Both of these isomers are known to be phenobarbital type inducers. The proportion of 2,4,5,3',4'5'-hexabromobiphenyl, which both a 3-methylcholanthrene and phenobarbital type inducer, increased in the roasted sirloin tip surface and broiled ground round patties.