by isomerizing linoleic acid the terms 34 conjugated linoleic acids 34 and 34 cla 34 as used herein are intended to include 9 11 octadecadienoic acid 10 12 octadecadienoic acid mixtures thereof and the non toxic salts of the acids the non toxic salts of the free acids may be made by reacting the free acids with a non toxic base the preferred method of synthesizing cla is that described in example 1 however cla may also be prepared from linoleic acid by the action of a linoleic acid isomerase from a harmless microorganism such as the rumen bacterium butyrivibrio fibrisolvens harmless microorganisms in the intestinal tracts of rats and other monogastric animals may also convert linoleic acid to cla s f chin j m storkson w liu k albright and m w pariza 1994 j nutr 124 694 701 the cla obtained by the practice of the described methods of preparation contains one or more of the 9 11 octadecadienoic acids and or 10 12 octadecadienoic acids and active isomers thereof it may be free or bound chemically through ester linkages the cla is heat stable and can be used as is or dried and powdered the cla is readily converted into a non toxic salt such as the sodium or potassium salt by reacting chemically equivalent amounts of the free acid with an alkali hydroxide at a ph of about 8 to 9 theoretically 8 possible geometric isomers of 9 11and 10 12 octadecadienoic acid c9.