1. A method for producing a plurality of product quality indicators, each operative to provide a machine-readable indication of exceedence of at least one threshold, the method comprising: providing at least one substrate strip including a plurality of barcodes in a first readable state; providing an additional substrate strip having formed thereon a plurality of ink impregnated areas; and joining said at least one substrate strip and said at least one additional substrate strip to form said plurality of product quality indicators, each of said plurality of product quality indicators including one of said plurality of barcodes in a first readable state and one of said plurality of ink impregnated areas, each of said plurality of ink impregnated areas being operative upon exceedence of said at least one threshold to color a portion of said at least one substrate strip, thereby causing each of said product quality indicators to assume a second readable state.
1. A method for producing a plurality of product quality indicators, each operative to provide a machine-readable indication of exceedence of at least one threshold, the method comprising: providing at least one substrate strip including a plurality of barcodes in a first readable state; providing an additional substrate strip having formed thereon a plurality of ink impregnated areas; and joining said at least one substrate strip and said at least one additional substrate strip to form said plurality of product quality indicators, each of said plurality of product quality indicators including one of said plurality of barcodes in a first readable state and one of said plurality of ink impregnated areas, each of said plurality of ink impregnated areas being operative upon exceedence of said at least one threshold to color a portion of said at least one substrate strip, thereby causing each of said product quality indicators to assume a second readable state. 2. A method according to claim 1 and wherein said providing at least one substrate strip comprises: providing a transparent substrate strip; printing, in a first color, said plurality of barcodes in said first readable state on said transparent substrate strip; forming a plurality of transparent areas alongside each of said plurality of barcodes in said first readable state by printing, in a second color, areas of said transparent substrate strip other than said plurality of barcodes and said plurality of transparent areas; providing an opaque substrate strip; and joining said transparent substrate strip and said opaque substrate strip.