The Museum of Fine Arts in Boston has banned two people and vowed to change protocols for its guards after minority middle school students said they were subjected to racism by staff and two visitors during a field trip last week.

School principal Arturo Forrest told the Boston Globe one museum staff member told students “no food, no drink, and no watermelon”. He said he also heard reports of museum security guards following his students while leaving white students alone, and that two visitors made racist remarks.

Museum officials said the staff member recalled saying “no food, no drink and no water bottles” and there was no way to definitively confirm or deny what was said or heard in the galleries. They also said guards were coming on and off breaks and that’s why students may have felt followed.

Nonetheless, museum officials apologized to students at the Helen Y Davis Leadership Academy in the Dorchester neighborhood.

“These young people left the museum feeling disrespected, harassed and targeted because of the color of their skin, and that is unacceptable,” museum director Matthew Teitelbaum said in a statement on Friday.

The museum said its investigation involved re-creating the group’s entire three-hour visit through security footage and speaking with dozens of people who interacted with them.

That led to the museum to identify the patrons they said made the disparaging remarks, revoking their membership, and banning them from the museum’s grounds. Museum officials said they will also serve the two, who were not identified, with a no-trespass cease-and-desist notification.

Officials said the areas visited by the students were patrolled by 13 guards and during the time of the visit the guards went on and off break and occasionally overlapped as they moved from one area or another.

Officials said based on the surveillance footage “it is understandable that, because of this movement, the students felt followed”.

Officials said the museum welcomes 60,000 schoolchildren annually.