1. A quality management system for products comprising: a multiplicity of product unit specific indicators each operative to provide a machine-readable indication of exceedence of at least one threshold by at least one product quality determining parameter, said machine-readable indication comprising a variable bar code having a first readable state and at least a second readable state, said first readable state and said at least a second readable state extending along a single axis, each readable state including digital indicia and at least start and stop code indicia, at least two digital indicia being different between said second readable state and said first readable state, wherein at least one of said start and stop code indicia which appear in said first readable state form part of said digital indicia in said second readable state and said second readable state includes additional indicia that appear at least one of before the digital indicia and after the digital indicia when the exceedence occurs; an indicator reader operative to read said product unit specific indicators and to provide output indications; and a product type specific indication interpreter operative to receive said output indications and to provide human sensible, product unit specific, product quality status outputs.