GUANAJUATO, Mexico (ValleyCentral) — Mexican officials have expressed concern after fungal colonies were spotted on some of the “Mummies of Guanajuato.”

The mummies are displayed at the “Museo De Las Momias De Guanajuato.” According to the museum’s website, the exhibit holds the mummified remains of ancestors ranging from 1870 to 1984, and is the largest collection of naturally formed mummies in the world.

Some of the mummies were recently transported to Mexico City as part of a travel exhibit from March 26 to 29. On the first day, over 5,000 people attended the exhibit, Mexican officials said.

According to a news release from Mexico’s National Institute of Anthropology and History, at least one of the mummies seen in photographs showed signs of “proliferation of possible fungal colonies” dating back to 2021.

The institute stated it never received a request for authorization, or advice, for the handling and transfer of the mummies.

“It is even more worrying that they are on display without biosafety conditions for the public that visits them,” the INAH stated.

For this reason, the institute stated analysis must be done to determine whether there is a risk for the mummified bodies, as well as those that manage and visit them.