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Food Chemical Safety Food Chemical Safety The food industry rarely studies the formation of toxic chemical materials arising from the handling, processing, or storage of foods. Solanin alkaloids in potatoes, hydrogen sulfide from eggs, and cholesterol oxides from cooked meats are some known hazards which are glossed over by technologists and regulators more interested in microbiological issues. In working with frying systems, we became concerned with acrolein and polymer as sources of complaints by operators and consumers. Acrolein (2-propenal; acrylic aldehyde) has a disagreeable choking odor, is a colorless vapor or yellowish liquid which distills from frying fats and oils. It originates from the glycerol released by hydrolysis of triacylglycerides during the frying process. The concentration of acrolein over a fryer is in direct proportion to its concentration in degraded oil. An important reason for limiting the breakdown of frying oils is to reduce exposure to this chemical which is a strong lachrymator and upper respiratory irritant. The concentration of acrolein at which all mucous membranes become irritated is 0.25 ppm for 5 minutes. The use of a fume hood over a food service or industrial fryer is needed to protect operators from acrolein. At least one possible metabolite of acrolein is believed to be carcinogenic. Thermal and oxidative processes during frying lead to the formation of "polymer" which consists of dimeric, trimeric, oligomeric and polymeric forms of triacylglycerides and their derivatives. These materials seem to be largely indigestible (and therefore of little caloric value), and irritating to the bowel causing distress and diarrhea. One consequence of consumption of "polymer" appears to be rapid voiding less than an hour following ingestion of food fried in degraded oil. The rapid voiding can cause carryout of unabsorbed vitamins and minerals which may take many hours to replenish. Similar comments have been noted in reports of tests with synthetic fat replacers. Though this is an unpleasant topic, the nutritional consequences of non-bioavailable lipids is an important area for further study.
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