Phenol odor quality determination

During the last decade parathion has been the most used organo-phosphorus insecticide. It has been proved to be valuable in crop protection 27). However, using this compound so much has also resulted in numerous accidental intoxications, and many have been lethal 28). In aquatic environments parathion hydrolyzes to yield p-nitro-phenol or oxidizes to yield paraoxon (25, 26). Baker (29) has shown that substituted phenols aflFect the odor quality of drinking water. p-Nitrophenol may be chlorinated at a water treatment plant to produce an odorous product. The U. S. Public Health Service has adopted 1 /xg/liter as a limit for phenolic compounds in water (10). Paraoxon is more toxic to insects and mammals than the parent compound parathion (27). The lethal dose (LD50) for male white rats is 14 mg/kg for parathion while that determined for paraoxon is only 3 mg/kg (30). Bioassay studies with fathead minnows indicated a Median Tolerance Limit (TLni) (96 hours) for parathion of 1.4 mg/liter and 0.3 mg/liter for paraoxon. 

Taste. Taste Is the human perception of chemicals In the mouth due to their Interaction with receptors on the tongue. Taste consists of four dimensions sweet, salty, sour and bitter. Taste Is affected by odor and texture, which makes it a complicated, subjective quality attribute, difficult to measure objectively (22). In fruits and vegetables, taste Is mostly determined by the types and amounts of carbohydrates, organic acids, amino acids, lipids and phenolics (5.71). CA combinations, to the degree that they modify changes in these constituents, can affect the taste of stored fruits and vegetables. Usually, extremely low O2 or high CO2 will result In off-flavors and reduced quality due to anaerobic respiration. The specific effect of CA on flavor depends on the crop Involved (2). 

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