Kisha Curtis appeared by video feed from the Essex County jail wearing an orange prison jumpsuit. Attorney Kelly Lerner, who represented Curtis for the arraignment, entered the plea on her behalf.
Police say Curtis tied the 1-year-old dog to a railing in her apartment building before leaving the state for more than a week.
A janitor later found it in a trash bin.
The pitbull, dubbed Patrick by his caretakers, is receiving treatment at an animal hospital.
Curtis is charged with two fourth-degree offenses for "tormenting and torturing" an animal by failing to provide food and water, the prosecutor's office said. Those carry a maximum jail sentence of 18 months and a fine of up to $10,000, but the prosecutor's office still has to determine whether those charges will be presented to a grand jury.
She also faces two abandonment charges that are disorderly persons offenses and are punishable by up to six months in jail with a $1,000 fine.
Essex County's courthouse has received more than 200 letters and faxes from around the world expressing concern for the dog and urging swift and harsh punishment for Curtis.
"She should not be treated with kid gloves," a writer from Colorado says. "Throw the book at her," another writes. One letter came from New Zealand.
Municipal Court Judge Amilkar Velez-Lopez continued Curtis' bail at $10,000 bond or $1,000 cash. She faces another court hearing in early May.
Anyone with information on the crime to call the NJSPCA tip line at 1-800-582-5979.
(The Associated Press contributed to this report)