GB1297195A - - Google Patents

Abstract

1297195 Test and device for use with coldstored food products FOOD CONTROL AB 12 March 1970 [13 March 1969] 11876/70 Heading B1X A method of indicating whether or not the temperature of a stored food product has exceeded a maximum temperature comprises exposing to the same ambient conditions as the food product and for the same time a given quantity of an enzyme and of a substrate for the enzyme, formation of the reaction product of these at temperatures above the maximum desired temperature producing a visual indication, for example by reaction of the reaction product to give a colour or by a loss of colour in the starting materials. The enzyme substrate &c. may be contained in a transparent capsule of plastics or glass or it may be placed on an adhesive tape backing and covered with a transparent protective layer, a piece being torn off a roll of the treated tape for attachment to the food product. Examples relate to test devices comprising carbamide, Nessler's reagent and urease, prepared by mixing ground frozen components and unit packaging in transparent plastics; filtration paper impregnated, with urease solution and dried, then impregnated with a buffered solution containing carbamide glutathione and bromcresol purple and sealed while wet between glass slides; a transparent capillary tube filled with white of egg which is then coagulated by boiling, the tube being placed in acidified pepsin solution. There is also reference to use of starch iodine and amylase; ethyl alcohol, NADP and Fehlings' solution.