the micro structure of the product treated with the secondary enzymes as shown in fig3 brings about a conspicuous reduction in the size of insoluble solid particles so that the texture in the mouth increases greatly while not wishing to be bound by any theory it is believed that insoluble solid portions are caused by the retrogradation of starch and that the secondary enzymatic treatment prevents starch from retrogradation thereby reducing the size of the solid portion it is generally accepted that the critical particle size to be sensed extraneous in the mouth is about 20 u03bcm the insoluble solids which have been treated with the fermenting strain and the secondary enzymes according to the present invention were measured by a microscope equipped with a micrometer and the results are shown in table 1 table 1______________________________________the effects of the particle size in insoluble solid portionsof rice derived lactic acid fermented product by the secondaryenzymatic treatment at fermentation particle size u03bcm lactic acid 0 02 0 02 u03b1 amylase amylasea control u03b1 0 02 glucoamylase______________________________________l acidophilus l a 27 0 11 8 8 2l bulgaricus l b 17 4 14 5 8 9l plantarum l p 23 0 21 0 12 8s thermophilus s t 20 6 8 8 6 9l a s t 22 7 10 5 12 5l b s t 24 2 13 5 9 3l p s t 19 8 10 3 8 1______________________________________ the control which has.