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A survey of nitrate-ion concentrations in plant-factory-cultured leafy vegetables was conducted. 344 samples of twenty-one varieties of raw leafy vegetables were examined using HPLC. The nitrate-ion concentrations in plant-factory-cultured leafy vegetables were found to be LOD-6,800 mg/kg. Furthermore, the average concentration values varied among different leafy vegetables. The average values for plant-factory-cultured leafy vegetables were higher than those of open-cultured leafy vegetables reported in previous studies, such as the values listed in the Standard Tables of Food Composition in Japan- 2015 - (Seventh revised edition). For some plant-factory-cultured leafy vegetables, such as salad spinach, the average values were above the maximum permissible levels of nitrate concentration in EC No 1258/2011; however, even when these plant-factory-cultured vegetables were routinely eaten, the intake of nitrate ions in humans did not exceed the ADI.

Degradation of four aflatoxins (AFB1, AFB2, AFG1 and AFG2) by food additives was investigated. Pure aflatoxins were degraded by treatment with solutions of acidic food additives (hydrochloric acid:HCl and sulfuric acid:H2SO4), alkaline food additives (sodium bicarbonate:NaHCO3, sodium carbonate:Na2CO3, sodium hydroxide:NaOH, sodium sulfite:Na2SO3, and sodium hypochlorite:NaOCl) and neutral food additives (potassium metabisulfite:K2S2O5, sodium bisulfite:NaHSO3, sodium hydrosulfite:Na2S2O4, hydrogen peroxide:H2O2, sodium chlorite:NaClO2, and ammonium peroxodisulfate:(NH4)2S2O8). The aflatoxins were treated with these neutral food additives under several conditions, and the effects of treatment temperature, time, and concentration of food additives on aflatoxin degradation were studied. Potassium bromate (KBrO3), potassium nitrate (KNO3), and sodium nitrite (NaNO2) had no effect on aflatoxins. Of the aflatoxin added to corn, 20% AFB, remained after treatment with the solution of NaHSO3 (0.5%, 48 h), but all of the AFB1 was completely degraded by NaClO2 (0.25%, pH 4, 48 h) and (NH4)2S2O8 (0.25%, 48 h) at 60°C. Of the aflatoxins added to butter beans, less than 20 and 5% of AFB1 remained after boiling treatment with a 2 and 0.5% solution of Na2S2O4, respectively. These findings suggested that aflatoxins can be degraded or removed by treatment with food additives during food processing.

A survey of the contamination of wheat, barley, and Japanese retail food by four Fusarium mycotoxins, deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin (T-2), and HT-2 toxin (HT-2), was performed between 2010 and 2012. A method for the simultaneous determination of the four mycotoxins by liquid chromatography-tandem mass spectrometry was validated by a small-scale interlaboratory study using two spiked wheat samples (DON was spiked at 20 and 100 μg/kg and ZEN, T-2, and HT-2 at 6 and 20 μg/kg in the respective samples). The recovery of the four mycotoxins ranged from 77.3 to 107.2%. A total of 557 samples of 10 different commodities were analyzed over 3 years by this validated method. Both T-2 and HT-2 were detected in wheat, wheat flour, barley, Job's tears products, beer, corn grits, azuki beans, soybeans, and rice with mixed grains. Only T-2 toxin was detected in sesame seeds. The highest concentrations of T-2 toxin (48.4 μg/kg) and HT-2 toxin (85.0 μg/kg) were present in azuki beans and wheat, respectively. DON was frequently detected in wheat, wheat flour, beer, and corn grits. The contamination level of wheat was below the provisional standard in Japan (1,100 μg/kg). The maximum contamination level of DON was present in a sample of a Job's tears product (1,093 μg/kg). ZEN was frequently detected in Job's tears products, corn grits, azuki beans, rice with mixed grains, and sesame seeds. A sample of a Job's tears product presented the highest ZEN contamination (153 μg/kg). These results indicate that continuous monitoring by multiple laboratories is effective and necessary due to the percentage of positive samples detected.

オクラトキシンＡ及びＢを、やはり腎毒性を有するカビ毒であるシトリニンと同時に分析する方法を用いて、20年以上にわたり食品の汚染実態調査を行ってきた。その結果、小麦、大麦、ライ麦、はと麦、そば粉、トウモロコシ等の穀類、コーヒー豆、カカオ、製餡原料豆等からオクラトキシンＡが検出された。オクラトキシンBは、オクラトキシンAの濃度が高い試料から、その1/3～1/10程度の濃度で検出された。そば、ハト麦等の穀類でオクラトキシンとシトリニンの複合汚染が高頻度で認められた。また、これまでは、確認法として使用していたTLC法及び誘導体化法の感度が低かったため、1 μg/kg未満のオクラトキシンを“検出”とすることができなかったが、LC/MS/MSを使用することにより、オクラトキシンを0.1 μg/kgまで確認することが可能となり、その結果、低レベルでの汚染が明らかとなった。近年、ブドウのオクラトキシン汚染の原因菌として注目されているAspergillus carbonariusのオクラトキシン産生能試験を行った。試験した６菌株のうち、４菌株にオクラトキシン産生能が認められた.

To validate a modified version of AOAC official method of analysis 995.10 as an official standard in Japan for determination of patulin in apple juice, an inter-laboratory study was performed in 11 laboratories using a non-contaminated sample, 2 naturally contaminated samples and 2 spiked samples of apple juice. For naturally contaminated apple juices, the relative standard deviations for repeatability and reproducibility were 3.2, 7.1% and 10.0, 21.7%, respectively. HORRAT values were 0.4, 0.9. The average recovery of patulin from spiked sample was 83.7%. The limit of quantification was calculated as 10 microg/kg. From these results, the method was thought to be suitable as an official standard for determination of patulin in apple juice in Japan.

A sensitive and selective method for quantification and confirmation of patulin in apple juice by GC/MS was developed. By this method, patulin was precisely determined and confirmed down to the level of 1 and 5 microg/kg in samples, respectively. Patulin was extracted with ethyl acetate from a sample and then hexane was added to the concentrated extract solution. Significant amounts of insoluble impurities were filtered off, followed by further clean-up by solid-phase extraction with combined silica gel and Florisil cartridges. The filtration step in a low-polarity condition was very effective to remove the impurities in the sample extract solution. The eluate from the cartridges was evaporated to dryness under reduced pressure and patulin was determined and confirmed by GC/MS after derivatization with 2.5% N,O-bis(trimethylsilyl)trifluoroacetamide ethyl acetate solution. Patulin was determined in the selected ion monitoring mode (m/z 226) and confirmed in the SCAN mode (m/z 40-340). The recovery from apple juice spiked with 10-500 microg/kg ranged from 93.4 to 100%. The limits of detection and quantification were 0.1 (S/N = 3) and 1 microg/kg (S/N = 30) of patulin in samples, respectively. Levels down to 5 microg/kg of patulin in sample were readily confirmed.

1982～1999年の18年間にピスタチオナッツ621試料のアフラトキシン（AF）汚染調査を行った．621試料中18試料からAFが検出され，検出率は約3%，検出量はAFB1で0.8～1380 ppbであった．AFが検出された試料のうち5 試料(28%)は日本の規制値(10 ppb)以下であったが，他の13 試料(72%)は規制値を超えており，100 ppb以上検出された試料は約40％であった．全体の検出率は高くはないが，検出量は多いという結果が得られた．AFが検出されたものを産地別に見ると，米国産が1試料(AFB1: 0.8 ppb)であり，他のすべてはイラン産であった．なお，1試料を除き，AFB群のみが検出され，AFG群は検出されなかった．厚生省による検査命令により，輸入時にピスタチオナッツは全ロット，AFの検査をすることが義務付けられており，規制値以上のAFを含むものは処分される．これにより，市販ピスタチオナッツのAF汚染は軽減されていると考えられるが，それでも，規制値を超えるAFが検出されている．市販品が規制値以上のAFを含まないようにするために，輸入時の検査をさらに厳しくする必要があると考える．

Samples of umeshu, a Japanese plum liqueur made from unripe plums, shochu and crystal sugar, were stored under fluorescent light, in the dark and in the refrigerator. The amount of ethyl carbamate formed in umeshu exposed to light or room temperature was larger than that in the dark or at low temperature. The amount of ethyl carbamate formed in umeshu to which cyanide had been added was larger than that in the absence of added cyanide. Thus, the amount of ethyl carbamate formed in the umeshu was increased by not only light and higher temperature, but also cyanide. Samples of model alcoholic beverages were stored under various conditions using red, yellow and blue cellophanes. The amount of ethyl carbamate formed in the model alcoholic beverage with blue cellophane was larger than in the cases of red and yellow cellophanes. It was found that the amount of ethyl carbamate formed in the model alcoholic beverage was increased by light in the wavelength range of 375-475 nm.

The conversion of aflatoxin B1 by six kinds of fungi, previously reported to assimilate aflatoxin B1, was investigated. The tested fungi were Aspergillus fumigatus, Paecilomyces lilacinus, P. inflatus, Humicola fuscoatra, Penicillium spinulosum, and Trichoderma aureoviride.After incubation at 25°C for 4 weeks, most of the tested fungi lowered the aflatoxin B1 level in the broth to less than 10% of the starting level. Penicillium spinulosum contained 80% of aflatoxin B1 in the mycelia, but the other fungi contained less than 30% of aflatoxin B1 in the mycelia. This fact suggests that aflatoxin B1 was converted by these 5 kinds of fungi.Only Humicola fuscoatra showed a marked difference in the aflatoxin conversion rate between intact and sterilized mycelia. Intact mycelia of the fungus degraded 90% of aflatoxin B1 but sterilized mycelia had no effect on aflatoxin B1. Aflatoxin B1 was converted in the mycelia of the fungus but not in the broth filtrate. These findings indicate that the conversion by Humicola fuscoatra was a biological reaction.The conversion products of aflatoxin B1 by Humicola fuscoatra were identified to be aflatoxicols A and B by TLC and HPLC, and all the reduced aflatoxin B1 was converted to aflatoxicols A and B.

The intake of total aflatoxins (AFT) and aflatoxin B(1) (AFB(1)) from food in Japan was estimated from AFT and AFB(1) concentration and frequency data in 24 foods (884 samples) from a 3-year retail market survey from the summer of 2004 to the winter of 2006, and by food consumption data from the National Health and Nutrition Survey performed in 2005. The AFT and AFB(1) survey revealed that peanut, peanut products, cocoa, chocolate, pistachio, white pepper, red pepper, almond, job's tears, buckwheat and corn grits are considered to be contributors of AFT (or AFB(1)) intake in Japan (maximum AFB(1) (AFT) levels ranged from 0.21 to 28.0 microg kg(-1) (from 0.21 to 9.0 microg kg(-1))) in AFT-contaminated food. A probabilistic approach using the Monte Carlo method was carried out to simulate an estimate of the AFT (or AFB(1)) intake distributions in each age group in Japan. In this study, AFB(1) intake ranged from 0.003 to 0.004 ng kg(-1) body weight day(-1) (from lower to upper limits), and the potential risk for cancer using a formula devised by the Joint Food and Agricultural Organization/World Health Organization (FAO/WHO) Expert Committee on Food Additives (JECFA) was estimated at 0.00004-0.00005 person/year/100,000 persons, even though this was in the higher levels (95.0th percentile) of the consumer population. The results suggest that the current dietary intake of AFB(1) in Japan has no appreciable effect on health.

Between 2004 and 2007 we examined foods from Japanese retail shops for contamination with ochratoxin A (OTA) and fumonisins B(1), B(2), and B(3). A total of 1,358 samples of 27 different products were examined for OTA, and 831 samples of 16 different products were examined for fumonisins. The limits of quantification ranged from 0.01 to 0.5 microg/kg for OTA and 2 to 10 microg/kg for the fumonisins. OTA was detected in amounts higher than limits of quantification in wheat flour, pasta, oatmeal, rye, buckwheat flour and dried buckwheat noodles, raisins, wine, beer, coffee beans and coffee products, chocolate, cocoa, and coriander. OTA was found in more than 90% of the samples of instant coffee and cocoa, and the highest concentration of OTA, 12.5 microg/kg, was detected in raisins. The concentration of OTA in oatmeal, rye, raisins, wine, and roasted coffee beans varied remarkably from year to year. Fumonisins were detected in frozen and canned corn, popcorn grain, corn grits, cornflakes, corn soups, corn snacks, beer, soybeans, millet, and asparagus. The highest concentrations of fumonisins B(1), B(2), and B(3) were detected in corn grits (1,670, 597, and 281 microg/kg, respectively). All of the samples of corn grits were contaminated with fumonisins, and more than 80% of the samples of popcorn grain and corn snacks contained fumonisins. OTA and fumonisins were detected in several food products in Japan; however, although Japan has not set regulatory levels for these mycotoxins, their concentrations were relatively low.

A survey was undertaken of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), ochratoxin A (OTA), and fumonisin B1 (FB1), B2 (FB2) and B3 (FB3) contamination of various retail foods in Japan during 2004-05. The mycotoxins were analysed by high-performance liquid chromatography (HPLC), liquid chromatography/mass spectrometry (LC/MS) or high-performance thin-layer chromatography (HPTLC). Aflatoxins (AFs) were detected in ten of 21 peanut butter and in 22 of 44 bitter chocolate samples; the highest level of AFB1, 2.59 microg kg(-1), was found in peanut butter. Aflatoxin contamination was not observed in corn products (n = 55), corn (n = 110), peanuts (n = 120), buckwheat flour (n = 23), dried buckwheat noodles (n = 59), rice (n = 83) or sesame oil (n = 20). OTA was detected in 120 out of 192 samples of oatmeal, wheat flour, rye, buckwheat flour, raw coffee, roasted coffee, raisin, beer, wine and bitter chocolate, but not in rice or corn products. OTA levels in the positive samples were below 13 microg kg(-1). AFs and OTA intakes through the consumption of foods containing cacao were estimated using the data for mycotoxin contamination in bitter chocolate and those for the consumption of foods containing cacao in Japan.

A liquid chromatographic (LC) analysis for the determination of seven amines, tyramine (Tym), histamine (Him), phenethylamine (Phm), putrescine (Put), cadaverine (Cad), spermidine (Spd) and spermine (Spm) in soybean paste (Miso), soy sauce (Shoyu) and its products was studied. The amines in the sample were extracted with 0.1N HCl and applied to a column of Amberlite CG-50 and derivatized with dansyl chloride for the application to the liquid chromatography. The LC separations were performed on a Finepak SIL C18S column with an acetonitrile-water elution gradient. The amines were confirmed by TLC for Him and by GC-MS for others with ethyloxycarbonyl derivatives. In the survey of commercial samples by this method, most of Miso samples and ann of Shoyu samples were found to contain these 7 amines. Tym and Him were determined in the range of nd-194, nd-177 μg/g in every kind of Miso, and 95.8-356, 62.8-232 μg/g in Shoyu and its products as average which were higher than the other amines. Shoyu, in general, had higher Him and Tym contents than Miso samples. However the contents of the other amines in both Shoyu and Miso samples were the same levels. It was considered that Tym, Him and Phm were produced by microorganism in a manufacturing process because these amines were not detected from such raw materials as koji (malted rice) and soy beans of Miso and Shoyu. Put, Cad, Spd and Spm were originated from the raw materials, because the contents of these amines in the samples were nearly the same as those of raw materials.

Ochratoxin A (OTA), ochratoxin B (OTB) and citrinin (CIT) in commercial foods were simultaneously determined and confirmed with high-performance liquid chromatography (HPLC) and liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). The samples examined were made up of cereal, fruit, coffee, and cacao products. The limits of quantification (S/N> or =10) of OTA, OTB and CIT were 0.1 microg/kg or less. Aflatoxins (AF), deoxynivalenol (DON) and fumonisins were also surveyed. Of 157 samples examined, 44 were contaminated with OTA at levels of 0.11 to 4.0 microg/kg. At least 2 positive samples were labeled as domestics. In most positive samples, the OTA level was low, less than 1 microg/kg. The highest incidence of OTA was observed in cacao powder (10/12), followed by instant coffee (5/7), cocoa (5/8) and raisin (6/13). OTB was found in fruit and cacao products containing relatively high levels of OTA. Co-occurrence of OTA, CIT and DON was found in cereal products, and co-occurrence of OTA and AF was found in cacao products. Approximately 30% of naturally contaminated OTA in roasted coffee bean moved into the extract solution when brewed with paper filter.

Methods using high-performance liquid chromatography with fluorescence detection (HPLC-FL) and using liquid chromatography with tandem mass spectrometry (LC/MS/MS) were developed for simultaneous determination of ochratoxin A (OTA), ochratoxin B (OTB) and citrinin (CIT) in cereal, fruit, and coffee products. The samples were extracted with ethyl acetate under an acidic condition, and then cleaned up with liquid-liquid separation. The test solutions were analyzed by reverse-phase HPLC-FL and LC/MS/MS. Mass spectral acquisition was performed in positive ion mode by applying multiple reaction monitoring. The performances of both detectors were almost equivalent. The recoveries of OTA and OTB were 87-111%, and that of CIT were 70-88%. The limits of quantification (S/N> or =10) of OTA, OTB and CIT was 0.1 mug/kg or less. These methods were considered to be useful for the determination of the three mycotoxins at low levels (0.1 microg/kg).

We conducted a survey of aflatoxin B1, B2, G1, and G2, ochratoxin A, and fumonisin B1, B2, and B3 contamination in various foods on the retail market in Japan in 2004 and 2005. The mycotoxins were analyzed by high-performance liquid chromatography, liquid chromatography-mass spectrometry, or high-performance thin-layer chromatography. Aflatoxins were detected in 10 of 21 peanut butter samples; the highest concentration of aflatoxin B1 was 2.59 microg/kg. Aflatoxin contamination was not found in corn products, corn, peanuts, buckwheat flour, dried buckwheat noodles, rice, or sesame oil. Ochratoxin A was detected in oatmeal, wheat flour, rye, buckwheat flour, green coffee beans, roasted coffee beans, raisins, beer, and wine but not in rice or corn products. Ochratoxin A concentrations in contaminated samples were below 0.8 microg/kg. Fumonisins were detected in popcorn, frozen corn, corn flakes, and corn grits. The highest concentrations of fumonisins B1, B2, and B3 in these samples were 354.0, 94.0, and 64.0 microg/kg, respectively.

To evaluate a method using a multifunctional clean-up column coupled with high performance liquid chromatography as an official analytical method for the determination of deoxynivalenol in wheat used as food or feed, an inter-laboratory study was performed in 12 laboratories using four naturally contaminated wheat samples and one spiked sample. The relative standard deviations for repeatability (RSDr) and reproducibility (RSDR) of naturally contaminated wheat were in the range 5.8–11.3% and 12.0–20.7%, respectively. The HORRAT was less than 1.0 in each sample. From the spiking test, the recovery rate, RSDr, RSDR and HORRAT value were 100.0%, 11.2%, 10.3% and 0.5, respectively. The limit of quantification is 0.10 mg/kg from the range obtained in a linear calibration. Thus, it should be useful as a sensitive and validated analytical method for the determination of deoxynivalenol in wheat intended for use in food and feed.

The modified Rankine colorimetric method for measuring sulfite added to food as a food additive has a low determination limit and is little influenced by interfering substances from foods. However, it can give erroneous results for foods containing Liliaceae Allium. So, four different methods, alkaline titration, a colorimetric method, ion chromatography and qualitative analysis with potassium iodate-starch paper, were examined. It was found that the sodium azide used in the colorimetric method forms sulfur dioxide during bubbling and heating. The proposed colorimetric method can be applied to food containing sulfur compounds, if sodium azide is omitted and 1% triethanolamine solution is used as an absorbent instead of 0.1 mol/L sodium hydroxide solution.

The concentrations of 7 non-volatile amines, tyramine (Tym), histamine (Him), phenethylamine (Phm), putrescine (Put), cadaverine (Cad), spermidine (Spd) and spermine (Spm) in the liquid part of "moromi" mash during soy sauce fermentation were studied. These amines, except for him and Cad, were detected during fermentation by the conventional production method in the laboratory. Put and Spd were detected at the beginning, and Tym, Phm and Spm appeared later; these 5 amines increased gradually during the fermentation. Put, Spd, Spm and Cad were present in the raw starting material for soy sauce; thus, Tym and Phm were produced by the fermentation. When "moromi" mash was added to liquid medium and cultivated, Tym was detected in some "moromi" mash and the other amines were not detected. Tym-producing bacterial strains were isolated from the liquid culture media of Tym-positive "moromi" mash. The Tym-producing strain was a gram-positive coccus. The conditions for production of amines by Tym-producing bacterial strains were examined. These strains grew and produced tyramine under various conditions, which may occur during soy sauce fermentation. Namely, Tym was produced at pH 5-10, at salt concentrations of less than 8%, under either aerobic or anaerobic conditions. During soy sauce fermentation, it is assumed that Tym would be produced by these strains during the early stages of soy sauce aging within a short period when the salt concentration and pH conditions are optimal for growth. Based on the bacteriological properties, the strains were identified as Enterococcus faecium. With the exception of Phm and Him, which did not exist in the starting raw material, non-volatile amines (including Put, Cad, Spd and Spm) were not produced and microorganisms producing them are not believed to be present during "moromi" fermentation.

Aflatoxins were determined in 3054 samples of foods or foodstuffs, including cereals, nuts, beans, spices, dairy products, dry fruits, and edible oil. Samples were collected in Tokyo from 1986 to 1990. Aflatoxins were found in rice products, adlay, corn, crude sugar, peanut products, pistachio nuts, brazil nuts, sesame products, butter beans, white pepper, red pepper, paprika, nutmeg, and mixed spices. The highest incidence of aflatoxin contamination was observed in nutmeg (80%), and the highest level of aflatoxin B1 was observed in pistachio nuts (1382 ppb).

In the manufacturing process for commercial cornstarch, corn is soaked in an aqueous solution of sodium hydrogen sulfite (NaHSO3), which reduces aflatoxin (AF) B1. The conversion product from AFB1 by treatment with NaHSO3 under similar conditions to those of the manufacturing process for cornstarch was investigated. After treatment of AFB1 standard, the conversion product (compound I) was isolated and identified by FAB-MS and NMR. A sulfo group was added to the double bond of bisfuran ring of AFB1. We applied the treatment to artificially and naturally AF-contaminated corn and confirmed that compound I was produced from AFB1. In the case of artificially AF-contaminated corn, 915ng of AFB1 was reduced, and 506ng of compound I was produced from 2, 000ng of AFB1 by NaHSO3. It was suggested that the conversion product is actually produced from AFB1 in the manufacturing process for commercial cornstarch. Effective detoxification is expected, because compound I is a watersoluble compound, and lacks the double bond in the bisfuran ring, which is activated to react with DNA.

A method is described for simple and rapid determination of aflatoxins in corn, buckwheat, peanuts, and cheese. Aflatoxins were extracted with chloroform-water and were purified by a Florisil column chromatographic procedure. Column eluates were concentrated and spotted on a high performance thin layer chromatographic (HPTLC) plate, which was then developed in chloroform-acetone (9 + 1) and/or ethermethanol- water (94 + 4.5 + 1.5)orchloroform-isopropanol-acetone (85 + 5 + 10). Each aflatoxin was quantitated by densitometry. The minimum detectable aflatoxin concentrations (μg/kg) in various test materials were 0.2, B1; 0.1, B2; 0.2, G1; 0.1, G2; and 0.1,M1.Recoveries of the aflatoxins added to corn, peanut, and cheese samples at 10-30 μg/kg were > 69% (aflatoxin G2) and averaged 91%, B1; 89%, B2; 91%, G1; 78%, G2; and 92%, M1. The simple method described was compared with the AOAC CB method, AOAC BF method, and AOAC milk and cheese method. These methods were applied to corn, peanut, and cheese composites spiked with known amounts of aflatoxins, and to naturally contaminated buckwheat and cheese. Recoveries were much lower for the BF method compared with our simple method and the CB method.

An analytical method was developed for the determination of isopropyl citrate in edible oil.The sample was dissolved in ethyl acetate and mono- and diisopropyl citrate were extracted with 5% sodium bicarbonate. The aqueous layer was acidified with phosphoric acid and isopropyl citrates were extracted with ethyl acetate. The ethyl acetate layer was dried with anhydrous sodium sulfate and evaporated to dryness. The residue was fluorescence-labeled with 4-bromomethyl-7-methoxycoumarin (Br-Mmc). Thin layer chromatography was used for the qualitative determination of fluorescence-labeled mono- and diisopropyl citrates.Qualitative determination was carried out as follows. The sample was hydrolyzed with potassium hydroxide solution. The hydrolyzed solution was washed with hexane and applied to the Amberlite IRA-402 column. Citric acid was eluted with 1N hydrochloric acid. The eluate was evaporated to dryness, and the residue was dissolved in water. High performance liquid chromatography was used for quantitative determination of citric acid.The recoveries of isopropyl citrates added to edible oil were in the range from 84% to 93% and the detection limit of monoisopropyl citrate was 5μg/g.

An analytical method was developed for the determination of copper chlorophyll and copper chlorophyllin in food. Firstly, copper chlorophyll was extracted from foods with ethyl acetate under mild alkaline conditions, and then copper chlorophyllin was extracted with n-butanol under mild acidic conditions. The ethyl acetate layer was washed with water, dried with anhydrous sodium sulfate and evaporated to dryness. The residue was dissolved in hexane-chloroform (9:1) and applied to a silica gel column. Copper chlorophyll was eluted with methyl ethyl ketone-methanol (3:2). The eluate was evaporated to dryness, and the residue was dissolved in acetone. The n-butanol layer was washed with water and evaporated to dryness. The residue was dissolved in methanol.Thin layer chromatography was used for the qualitative determination of copper chlorophyll and copper chlorophyllin. Atomic absorption spectrometry was used for quantitative determination of copper.The recoveries of copper chlorophyll and copper chlorophyllin added to foods at levels of 10ppm were in the range from 80% to 97% and the detection limit of copper was 0.1ppm. By using this method, 41 commercial food samples were analyzed. Copper chlorophyll was detected in 8 samples of processed bracken.

The natural occurrence of mycotoxins in edible oil and the fate of mycotoxins during oil-refining processes were investigated.During the 2-year period 1984-1985, 60 samples (corn, peanut, cotton seed, olive, safflower, salad, walnut and sesame seed oil) were analyzed for aflatoxins, trichothecenes and zearalenone. Aflatoxins were detected in 5 of 8 samples of the peanut oil (aflatoxin B1, 0.52-0.72ppb; B2, 0.09-0.22ppb; G1, 0.07-0.08ppb and G2, 0.01ppb).Crude oils, obtained from corn germ, were spiked with aflatoxins (0.8-1.0ppm), deoxynivalenol (8ppm), nivalenol (8ppm) and zearalenone (10ppm), then refined through processes simulating the practical oil-refining procedures. No detectable mycotoxins remained in the edible oil. In particular, the neutralization processes including alkaline refining and washing, and decolorizing processes eliminated all measurable traces of mycotoxins from the oil.