Food grade ink jet inks for printing on edible substrates

A method of applying an edible colorant to a surface of an edible substrate, the method comprising ink jet printing onto the surface a food grade colored fluid comprising a food-grade dye, about 25 wt. % to about 95 wt. % 1,2-propanediol, about 1 wt. % to about 50 wt. % glycerine, about 0.01 wt. % to about 5 wt. % surface tension modifier selected from the group consisting of sorbitan esters, fatty acids, mixtures of fatty acids, and esters of fatty acids, and no more than about 10 wt. % water;

• wherein the colored fluid has a surface tension of no more than about 38 dynes per cm at 25° C.

A method of applying an edible colorant to a surface of an edible substrate, comprising inkjet printing onto the surface a food grade colored fluid comprising a food grade dye, at least about 50 wt. % 1,2 propanediol, and a surface tension modifier selected from the group consisting of sorbitan esters, fatty acids, mixtures of fatty acids, and esters of fatty acids, the colored fluid having an inorganic salt content of no more than about 0.1 wt. %.

A method of applying an edible colorant to a surface of an edible substrate, comprising inkjet printing onto the surface a food grade colored fluid comprising a food grade dye, at least about 70 wt. % 1,2 propanediol, glycerine or a mixture thereof, no more than about 10 wt. % water, and a surface tension modifier selected from the group consisting of sorbitan esters, fatty acids, mixtures of fatty acids, esters of fatty acids, lecithins and mixtures thereof.

A method of applying an edible colorant to a surface of an edible substrate, comprising inkjet printing onto the surface a food grade colored fluid comprising a food grade dye, a surface tension modifier selected from the group consisting of sorbitan esters, fatty acids, mixtures of fatty acids, polyol monoesters and esters of fatty acids, lecithins, and mixtures thereof, and at least about 70 wt. % 1,2 propanediol, glycerine or a mixture thereof, provided that the colored fluid comprises at least about 10 wt. % 1,2-propanediol.