Polybrominated diphenyl ethers (PBDEs) have been used worldwide as additive flame retardants in polymeric materials. Commercial products consist predominantly of deca-, octa-, and pentabromodiphenyl ether mixtures. PBDEs are resistant to degradation in the natural environment and Penta-BDE in particular accumulates in the fatty tissues of fish, birds and mammals (including humans). Several toxic effects on the thyroid system or on neurodevelopment have been reported in experimental animals exposed to PBDEs. It is likely that human exposure is predominantly through the ingestion of contaminated food and/or mother's milk. The potential health effects of dietary exposure to PBDEs have now become a great concern because of the increasing PBDE levels in the biosphere. In this review, published information on the toxicology of PBDEs, levels in foodstuffs and human milk, and analytical methods has been compiled.

View full abstract

Genetially modified organisms (GMOs) were explored in food samples obtained from November 2000 to March 2003 in the Tokyo area by using PCR and real-time PCR techniques. The existence of Roundup Ready Soybean (RRS) was surveyed in processed foods derived from soybeans, such as tofu, boiled soybean, kinako, nama-age, abura-age, natto, miso, soymilk and yuba. RRS was detected in 3 of 37 tofu, 2 of 3 nama-age, 2 of 3 yuba and 3 of 3 abura-age samples. The CBH351 in 70 processed corn foods, NewLeaf Plus and NewLeaf Y in 50 processed potato foods, and 55-1 papaya in 16 papayas were surveyed. These GMOs were not detected among the samples. Qualitative and quantitative analyses of RRS and genetically modified (GM) corn were performed in soybean, corn and semi-processed corn products such as corn meal, corn flour and corn grits. RRS was detected in 42 of 178 soybean samples, and the amount of RRS in RRS-positive samples was determined. The content was in the range of 0.1-1.4% in identity-preserved soybeans (non-GMO), and 49.8-78.8% in non-segregated soybeans. On the other hand, GM corns were detected in 8 of 26 samples. The amount of GM corn in GM corn-positive samples was in the range of 0.1-2.0%.

View full abstract

A microbiological method for screening of residual benzylpenicillin (PCG), oxytetracycline (OTC) and spiramycin (SPM) in meat using a single mixed mode, reversed-phase and cation-exchange cartridge was developed.
A meat sample was extracted with 0.1 mol/mL pH 4.5 phosphate buffer and the extract was applied to a MCX cartridge. The cartridge was washed, and adsorbed antibiotic residues were eluted with acetonitrile for acidic fractions and acetonitrile containing 5% ammonia solution-0.1 mol/mL pH 4.5 phosphate buffer (9 : 1, v/v) for basic fractions. Each eluate was evaporated to dryness and the residue was dissolved in phosphate buffer to prepare test solutions for microbiological assay. When the diameter of the inhibition zone was more than 12 mm, the result was considered positive. In this method, the average recoveries of PCG at 0.05 μg/g, OTC at 0.1 μg/g and SPM at 0.2 μg/g were 70%, 92% and 84%, respectively. Tolerances of the three antibiotics were detected .
All the results demonstrate that this method is simple, rapid and useful for screening of these three antibiotic residues in meat.

View full abstract

A simple and rapid method was developed for the analysis of mepiquat chloride in grape, wine and juice by high-performance liquid chromatography with electrospray tandem mass spectrometry (LC/MS/MS). Mepiquat chloride was extracted with water-methanol (1 : 1). Extracted solution was adjusted to pH 10 with ammonia solution. A part of the extracted solution was cleaned up on a styrenedivinylbenzene (SDVB) cartridge for LC/MS/MS. The LC separation was performed on a C18 column (50 mm×2 mm i.d.) using 0.1% IPCC-MS7-methanol (60 : 40) as the mobile phase at a flow rate of 0.2 mL/min. The mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of mepiquat chloride from fresh grape, wine and juice fortified at 5 μg/kg and 50 μg/kg were 84.5-96.1%. The lower limit of quantification was 1 μg/kg. Fourteen fresh grape samples, 14 wines (white), 36 wines (red) and 11 juice samples were analyzed by this method. Mepiquat chloride was detected in 5 fresh grape samples, 3 wines (white) and 1 wine (red) at the level of 12.8-199 μg/kg, 5.7-47.7 μg/kg and 24.1 μg/kg, respectively.

View full abstract

A survey concerning foods for which complaints of fungal contamination had been made was carried out by distributing and retrieving a questionnaire. The subject of the survey was foods that were examined for fungi by institutes and laboratories belonging to regulatory agencies following consumers' complaints or upon request from food companies to solve problems. We analyzed 1,096 cases recovered from 40 organizations located in 30 prefectures. Most foods with fungal contamination were “cake and snacks”, “beverages” and “bakery products”, and processed and cooked foods and beverages accounted for more than 90% of the complaints. The numbers of cases were greater in the summer and less in the winter. The major fungal genus detected in the suspect foods were Penicillium, Aspergillus and Cladosporium. Aspergillus niger was the dominant species contaminating bakery products. Complainers reported physical symptoms including diarrhea, stomach ache, nausea and vomiting in 18% of the cases in which they had eaten or drunk fungus-contaminated foods or beverages. There was no clear difference in the fungi detected between foods and beverages that caused symptoms and those that did not. The proportion of beverages was greater in the foods that induced symptoms than in the whole of the foods for which complaints were made. This was presumed to be because consumers drank fungus-contaminated beverages more often than they ate fungus-contaminated foods.

View full abstract

A rapid and simple DNA extraction method is needed to detect genetically modified recombinant DNA in soybean kernels and processed foods. However, since various kernels and processed foods differ greatly in form, a uniform DNA extraction method has proved elusive. The silica-base resin DNA extraction method does not use any organic solvent, and the operation is simple and the cost per extraction is low, although the frequency of its use is very low and few domestic reports exist. We therefore studied suitable conditions for a silica-base resin method. We also developed the method to get more pure DNA from soybean kernels. The silica-base resin method was found to be adequate for extracting DNA from various processed foods for PCR amplification with endogenous gene primers. In the case of DNA extraction from soybean kernels, pure DNA could be efficiently extracted after pre-heating the soybean suspension in TNE buffer. The extracted DNA showed higher ratios of absorption at 260 nm/280 nm and 260 nm/230 nm than those for samples obtained with previous methods. Moreover, our observations suggested that the extraction time could be reduced to within 30 min for processed foods such as tofu.

View full abstract

A multiresidue method that enables determination of many pesticides in agricultural products by GC-ECD was studied. First, 63 pesticides were selected as agrochemicals commonly used in crop protection in this country, and/or found in agricultural products over the past 6 years (April 1996-March 2002) in Aichi Prefecture. A sample was extracted with acetonitrile and the acetonitrile layer was separated by salting-out. The extract was purified on a GPC system with a graphitized carbon columns, and then by a Florisil mini-column fractionation. The test solution was subjected to one-injection, dual-column GC with dual ECD (column: Stx-CLPesticides and Stx-CLPesticides2). The detection limits of the pesticides were in a suitable range (0.0001-0.01 μg/g) for monitoring pesticide residues in agricultural products. The method was applied to 203 commercial agricultural products to demonstrate its suitability for routine analysis.

View full abstract