Donna Ambrosio-Ruglio is held in the Morris County Jail on $75,000 bail, charged with child endangerment.
According to the arrest affidavit, the boy told police the 45-year-old yelled at him that the cream cheese would kill the dog.
A criminal complaint says the boy sustained an abrasion to his head and bruising on his back.
The Daily Record of Parsippany reports Ambrosio-Ruglio was caring for the boy at her Randolph home.
It is not immediately clear whether she has retained an attorney.
Information from: Daily Record