[in Japanese]

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Recently, complaints about the food were increased. There are many chemical substances in the living environment, and it was moved to food. And the food safety was disturbed by the take of polluted food. I showed some examples about the adsorption of the chemical substances to the food. It is in particular important not to put the volatility chemical substance near food. In addition, it is important as a container for food to choose the polymer film which a volatile chemical substance is hard to penetrate.

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Lactic acid bacteria and yeast were major cause of food spoilage and resistant of antimicrobial agent in Japan. Typical food spoilage caused by lactic acid bacteria and yeast were as follows : swelling, offensive smell (ethanol, thinner, banana, petroleum, acid, burnt or caramel), ropiness, surface slime. These microorganisms were contaminated from food manufacturing factory. Characteristic of food spoilage by lactic acid bacteria were as follows : food spoilage were caused from pH 9.0 to pH 4.0. Characteristic of food spoilage by yeast were as follows : food spoilage were caused by anerobic culture condition.

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Off-flavor development in clear bottled citrus juices by photosensitized oxidation of chlorophylls during storage under the fluorescent light exposure was summarized. The citrus-like aroma was decreased due to oxidation of terpenoid while various odor-active aliphatic carbonyl compounds which smell metallic or oily were observed by fluorescent light exposure. The major compound contributing to the light-induced off-flavor was identified as 1-octen-3-one. The light-induced off-flavor was rapidly developed by the fluorescent light irradiation 1 day. It was proven that the photosensitivity of the chlorophylls promoted the oxidation of lipid, which was precursor of 1-octen-3-one, and the chlorophyll photosensitivity was increased at low pH. Antioxidation treatment such as the addition of vitamin C and the use of oxygen barrier plastic bottles are effective for the control of off-flavor development.

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The off-flavors of beer formed during the production stage and at the market were explained. The well-known off-flavors are earthy flavor from water, staling flavor such as cardboard and aging flavor which might be involved in mashing and boiling process, hydrogen sulfide during the fermentation process, vicinal diketones during the conditioning process and lightstruck character at the market. In this paper, the authors explained origins and control of formation.

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In Yokohama, various consultation and complaints are sent to the Health and Welfare Center about food safety. The complaint that need investigation is analyzed in Yokohama City Inst. of Public Health.
There were 57 analyses of the Off-flavor for five years of from April, 2004 to March, 2009. It was 35 cases that confirmation was possible of Off-flavor by sensory test. This time, the Off-flavor was roughly classified into the putrid odor, the oil smell, the chemical smell, and other Off-flavor. I take up an example by each classification and report a result of the analysis.

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