From Age of Sail, where there is further explanation.
Cheese was one of the staple foods on a British man o’ war. Twelve ounces of cheese were issued per sailor each week... in the early part of the 18th Century the cheese favored by the Victualling Board was Suffolk cheese. Suffolk cheese was made from milk that had been “thrice skimmed” of cream. The resulting product kept for a long time, unfortunately, it was hard and inedible. A writer discussing English agriculture in the first half of the 19th Century observed:
“Suffolk cheese, from its poverty, is frequently the subject of much humour. It is by some represented as only fit for making wheels for wheelbarrows ; and a story is told, that a parcel of Suffolk cheese being packed up in an iron chest and put on board a ship bound to the East Indies, the rats, allured by the scent, gnawed a hole in the chest, but could not penetrate the cheese.”
20 May 2009