A method was developed for the determination of sodium chondroitin sulfate (ChS) in foods such as salad dressings, mayonnaises and fish sausages.
Alcian blue reagent was added to the sample solution extracted from these foods, and ChS was precipitated selectively as ChS-alcian blue. The precipitate was dissolved in monoethanolamine and determined colorimetrically at 615nm. In this method, the recoveries were 89.3-105.9% and the detection limits were 0.01% for salad dressings and mayonnaises, and 0.02% for fish sausages.
For qualitative analysis, the precipitate obtained from the sample solution by adding excess methanol was solvolyzed with methanol-hydrochloride followed by trimethylsilylation. Capillary gas chromatography and gas chromatography-mass spectrometry were carried out to identify D-glucuronic acid formed from ChS.

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Sterile seafood media were prepared by autoclaving fish muscle homogenate to which an equivalent amount of saline had been added. Common mackerel (Scomber japonicus), black tiger shrimp (Penaeus monodon) and neon flying squid (Ommastraphes bartrami) were used to prepare growth media.
In order to compare the spoilage patterns of yeasts and bacteria, 5 yeast species and 4 bacterial species isolated from seafoods were inoculated at 10⁵ cells per gram into the 3 kinds of seafood media, and incubated at temperatures of 5, 15 and 25°C for up to 2 weeks. Sensory signs of spoilage such as softening, odor or slime were observed, the pH values were taken after 2, 4 and 7 days of incubation, and total volatile basic nitrogen (TVB-N) values were determined according to the microdiffusion method of Conway after 2 weeks of incubation.
Results by yeast strains. (1) Candida lipolytica: The muscle tissue of the mackerel medium incubated at 25°C began to soften after 2 days (pH 6.13), and was damaged after 4 days (pH 6.91). Ammoniacal odor and slime were produced after a week (pH 7.93), and a strong putrid smell was generated after 2 weeks (pH 8.27). The TVB-N value in the mackerel medium at 25°C amounted to 634mg-N/100g. The production of TVB-N was highest by C. lipolytica among the 5 yeast species tested. (2) Trichosporon pullulans: This strain showed an optimum temperature of 15°C, giving higher values of TVB-N at 15°C than at 25°C. The TVB-N value in the mackerel medium at 25°C was 121.3mg-N/100g. (3) Tr. cutaneum: This strain affected the 3 kinds of media to almost the same degree. A strong ammoniacal odor was detected in the squid medium at 25°C (pH 8.20, TVB-N of 116.7mg-N/100g). (4) Cryptococcus laurentii: This strain especially affected the squid media. (5) Candida sake: Although the TVB-N values were the lowest among the 5 yeast species, the values in the squid medium at 15 and 25°C exceeded the spoilage value at an early stage-30mg-N/100g.
Results by the bacterial strains. (1) Pseudomonas fluorescens: The spoilage patterns and the amounts of TVB-N produced were almost similar to those in the case of C. lipolytica. However, the values at 5°C were higher than those of C. lipolytica. (2) Bacillus subtilis: The spoilage patterns were similar to those of Tr. cutaneum. (3) Alcaligenes sp.: This isolate from a spoiled black tiger shrimp affected chiefly the shrimp media. The TVB-N value was 140.0mg-N/100g shrimp medium at 25°C (pH 8.36; strong ammoniacal odor and slime were observed). (4) Staphylococcus epidermidis: The spoilage patterns were similar to those of C. sake and Cr. laurentii. The TVB-N values at 5 and 25°C did not increase over the spoilage value at an early stage. The degree of spoilage by the strain was the least among the 4 bacterial species tested.
It was clearly evident that the yeasts acted in the same manner as the bacteria, putrefying the seafood media, emitting an ammoniacal odor, and increasing the amounts of TVB-N production.

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Four bacterial strains isolated from spoiled seafoods were identified, and their growth temperature ranges were determined. Proteolytic activity on nutrient agar plus 1% skim milk and lipolytic activity on butterfat in Crossley's agar were determined under various conditions of incubation for 2 weeks at 5, 15 and 25°C.
Pseudomonas fluorescens S-1 was isolated at the cell number of 2.4×10⁵ per gram from a spoiled common mackerel (Scomber japonicus). This strain was a gram negative aerobic rod with polar flagella, and produced diffusible fluorescent pigment and arginine dihydrolase. The strain was psychrotrophic, having a growth temperature range from 0 to 30°C with the optimum temperature at about 25°C. The strain showed both proteolysis and lipolysis within 2 days at 25°C, within 4 days at 15°C, and within 14 days at 5°C.
Bacillus subtilis S-8 was isolated at the cell number of 1.1×10⁸ per gram from a spoiled neon flying squid (Ommastraphes bartrami). This strain was a gram positive endosporeforming rod, and hydrolyzed gelatin, starch and casein. The strain showed both proteolysis and lipolysis within one day at 25°C, within 3 days at 15°C, and within 4 days at 5°C.
Staphylococcus epidermidis S-6 was isolated at the cell number of 5.5×10⁷ per gram from a spoiled black tiger shrimp (Penaeus monodon). This strain was a gram-positive yellow pigmented coccus. It grew on mannitol salt agar, but it did not produce lecithinase or coagulase. Both proteolysis and lipolysis of the strain were positive within 2 days at 25°C. The proteolysis at 5 and 25°C was negligible.
Alcaligenes sp. S-4 was isolated at the cell number of 6.1×10⁶ per gram from a spoiled black tiger shrimp. This strain was a gram negative aerobic coccal rod with peritrichous flagella. Its coenzyme Q system was Q-8, its GC content of DNA was 57.8mol%. The strain demonstrated neither proteolysis nor lipolysis.
These 4 bacterial strains will be employed as test strains for microbiological and chemical analysis in further investigations on spoilage of seafoods.

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In determining the antioxidants (BHT, BHA) in smoked foods, interference by coexisting substances is often found. Extraction and characterization of the interfering substances are reported in this paper.
The extract from smoked squid was purified by preparative liquid chromatography. One crystalline material (A) and two colorless oils (B, C) were obtained. Analysis of their mass, UV and NMR spectral data revealed their structures. Compounds A, B and C are 2, 6-dimethoxyphenol, 4-methyl-2, 6-dimethoxyphenol and 4-ethyl-2, 6-dimethoxyphenol, respectively. Compounds B and C were synthesized for confirmation of the structures.
Smoked foods contain these compounds as flavor constituents. Qualitative analysis with several columns having different characteristics is necessary for identification of BHT and BHA in such foods by GC.

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The residues of ethylene dibromide (EDB; 1, 2-dibromoethane) in wheat, corn and grainbased products imported during 1984 to 1986, the degree of decrease of EDB residues in them during storage, and the distribution of EDB residues after milling and baking were investigated by using a Dean-Stark apparatus and by gas chromatography with ECD. Wheat grains imported from Canada and Australia in 1984 and 1986 were not contaminated at all with EDB. Some grains of Dark Northern Spring wheat and Hard Red Winter (Semi-Hard) wheat imported from the U. S. A. in January 1984 were significantly contaminated with EDB at levels of more than 100ppb (maximum 201ppb) but all of three samples imported in 1986 contained only traces of EDB. EDB residues were at a trace level or not detectable in bread made from flours derived from wheat samples which were contaminated at levels more than 100ppb without storage or after storage for more 3 months at room temperature. EDB was not detected at all in marketed crackers and biscuits made in Japan and purchased in February 1984 but it was detected at a trace level in marketed crackers and cookies made in the U. S. A. and purchased on the same date. Furthermore, marketed popcorn grains purchased in February 1984 and imported from the U. S. A. was contaminated with EDB at high levels of more than 200ppb (maximum 1700ppb), though all of three similar samples purchased in March 1985 contained no detectable EDB.

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[in Japanese]

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