The teen was arrested Friday and released to the custody of his parents; police did not know whether he had a lawyer.
"This was an extremely disturbing event on many levels," Gloucester County Prosecutor Sean Dalton said at a news conference. "Any statements like these that can cause harm or grave concern must be addressed as quickly we possibly can."
Dalton said the case would be handled in juvenile court in neighboring Atlantic County, where the boy lives. He would not say whether the boy has a criminal record, citing the teen's age, and would not disclose the teen's race, saying that did not factor into the investigation.
The 16-year-old has been charged with harassment and bias intimidation.
Authorities would not say whether the announcement was planned or made impulsively. Police said they were also investigating a teenage boy who accompanied the suspect to the store, but the other boy has not been charged.
Officials for Bentonville, Ark.-based Wal-Mart Stores Inc. said the announcement was "unacceptable," and Dalton praised the company for its strong cooperation in the investigation.
"We're pleased this matter is resolved," Walmart spokesman David Tovar said in a statement issued after the news conference. "We have updated our intercom system at this store to prevent this from happening again. We again apologize to all of our customers and associates who had to listen to something so offensive."
Although a manager quickly went on the intercom system and apologized for the remark, many customers expressed their anger to store management. Some community members said Saturday that they've heard reports of similar incidents happening at the store in recent months that were not reported to police.
"We are concerned about that, and we're looking into these incidents. We want to work with the community to make sure these types of incidents don't happen," said Loretta Winters, president of the Gloucester County chapter of the National Association for the Advancement of Colored People.
Winters said she hopes the boy will get counseling and be educated about sensitivity so he can understand the consequences of his actions.
"I'm assuming this person didn't realize how hurtful his comments were," she said.
The incident was the latest in a series of problems the retailer has had in its dealings with minorities and women.
There have been several past instances of black customers claiming they were treated unfairly at Walmart stores, and the company faced lawsuits alleging that women were passed over in favor of men for pay raises and promotions.
In February 2009, the retailer paid $17.5 million to settle a class action lawsuit alleging racial discrimination in its hiring of truck drivers.
And the U.S. Equal Employment Opportunity Commission sued the company in May 2009, claiming some Hispanic employees at a Sam's Club subsidiary in California were subjected to a hostile work environment. That suit alleges managers failed to stop repeated verbal harassment, including the use of derogatory words, against employees of Mexican descent.
However, the NAACP has said the company has worked hard in recent years to show it cares about diversity.