Mexican federal health regulators expanded their investigation into a Salmonella outbreak at the General Hospital of Mexico in Mexico City on Saturday, after the number of hospitalised staff climbed above 50. The hospital confirmed the rising toll in a statement.

The outbreak began earlier in the week when 41 doctors were hospitalised with gastrointestinal symptoms after eating at the facility. Laboratory testing confirmed Salmonella, prompting the hospital's director to suspend food service and order cultures of kitchen staff, water and stored ingredients.

Cofepris, Mexico's federal commission for protection against sanitary risks, said its inspectors were sampling the central kitchen and reviewing cold-chain records to identify the contaminated source. The Mexico City health secretariat said affected doctors were receiving intravenous fluids and antibiotics, and that most were in stable condition.

The episode has raised questions about food-safety oversight at one of the country's largest public hospitals, which treats thousands of patients daily. Hospital administrators said outpatient and emergency services continued to operate normally, with meals brought in from external certified suppliers during the shutdown.

The federal Health Secretariat said no patients had been confirmed among the cases and that the outbreak appeared limited to staff who used the medical dining hall. Officials pledged a full report once laboratory results identified the strain and its origin.