Green’s Dictionary of Slang

rouge n.

[the red jam that ‘makes up’ the plain bread]

(S.Afr. prison) bread.

[SA]A. Lovejoy Acid Alex 103: Rouge turned out to be two thick slices of plain brown bread smeared with horrible-looking reddish-pink fruit jam. [Ibid.] 206: I’ve worked out a way to steal rogue when we get tand at night.