Health inspectors said they had found E. Coli bacteria in spaghetti meals prepared for Navarre's hospitals by the private company Mediterránea de Catering.
Inspector Agurtzane Jiménez said the spaghetti didn't present a health risk and there was no need to ring the alarm bells.
The finding is, however, the latest in a long line of problems involving the services of Mediterránea de Catering.
The health inspectors admitted they had discovered 22 such cases since their decision to contract the private firm to provide food to the region's hospitals, reported Diario Córdoba on Thursday.
A review of the company's practices had uncovered "inadequate clothing" among staff, lipstick on cups used for hospital breakfasts, dirty plates, open rubbish bags and yoghurt tubs that had been left out of refrigerators.
Inspectors also stressed the failure of Mediterránea de Catering to properly heat up food.
One plate of cold lasagne tested positive for a listeria species.
The presence of listeria can lead to the illness listeriosis, which has a 20 percent mortality rate.
The head of Navarre's health services said, however, that a man who had died in the hospital had not been contaminated by the lasagne.
On hearing the details of the investigations, Navarre's left-wing opposition called for Mediterránea de Catering to have its food provision licence withdrawn.
Last week, a citizen's group presented the Navarre parliament with a petition bearing 23,000 names calling for the company to be stripped of their catering contract.
In March, a 25-year-old Mediterránea de Catering employee required back surgery after he was run over by a 200kg food cart.