Green’s Dictionary of Slang

pork, bacon or any pigmeat.

1674		Head Canting Academy (2nd edn) s.
c.1698		B.E. Dict. Canting Crew n.p.: Grunting Pecck [sic] c. Pork.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1836		W.H. Smith ‘The Thieves’s Chaunt’ in Farmer Musa Pedestris (1896) 121: Oh! grunting peck in its eating / Is a richly soft and savoury thing.