On the kitchen shelf is a box of "Moon Sweet Prunes". This is a pun on Sunsweet Prunes, a brand still sold today.
On the kitchen shelf is a box of "Spaghet". This is a stereotyped Italian immigrant dialect pronunciation of "spaghetti" that was common in American "ethnic" comedy routines during much of the 20th Century.
Wonderful attention to background detail, as typical for cartoon shorts of this era. From a kitchen with all the very latest accessories, to the worn baseboards, to the dustpan and broom, it's all carefully rendered.
Audiences of the time would have appreciated seeing dinner and a show as performed by the rodents. As America came out of the Depression era, this was a common part of an evening out, from the most humble to a night at the Waldorf in NYC. Several of the mouse musicians are styled after popular band artists of the day (Benny Goodman, etc).