In A Tree Grows In Brooklyn, why does Francie's mother warn her to never get ground meat off the plate ?
After their father has lost his job as a janitor at a school because of his drinking, he obtains a job as a singing waiter; however, his wages are not sufficient to support his family. Consequently, his wife Katie works as the janitor of the building they live in for the rent, and the children, Francie and Neeley gather junk which they sell to a dealer on the week-end.
Also on the week-end, Francie and Neeley go to the butcher's for their mother. With strict instructions from their mother, they are told to go to one butcher for ground round steak, but not to buy it if it is already ground because some of it may be dried upon the plate, and the meat may not really be beef. After Francie tricks the butcher into giving her ten cents' worth of beef, then she asks to have it ground with an onion. Then, she goes to another butcher, but has Neeley hold the meat outside the shop so Mr. Hassler does not see the meat because he will be angry that they bought meat elsewhere.(Mr. Hassler grinds his meat in a back room, so Katie does not trust it). In this shop, Francie asks for a soup bone and are touched by the kindness of the butcher, who adds a slice of liverwurst for free to their package.
Francie was sorry that she deceived that kind man by buying the meat elsewhere.
Francie and Neeley then depart, glad that the meat bartering is finished.