Almost half of hospital kitchens and canteens in England have poor hygiene standards, a dossier has suggested.
Cockroaches and vermin were found in some hospital kitchens
The Liberal Democrats said inspection reports obtained under the Freedom of Information Act painted a "shocking picture" of hospital food hygiene.
Vermin, cockroaches and the storage of medical and food items together were reported by some local authorities.
The Food Standards Agency said it would expect any authority with hospital food hygiene problems to take action.
The Liberal Democrats requested environmental health officers' inspection reports on hospital food preparation areas at a quarter of all English local authorities.
The papers revealed that of the 377 hospitals included, 173 - 46% - displayed poor levels of cleanliness in their kitchens or canteens and 68 did not fulfil the legal requirements for storing food.
Almost a fifth of the hospitals (66) were found to have stored food at the wrong temperature or in unsafe conditions, while 18 had out-of-date food.
In addition, 11 hospitals had problems with vermin and 57 reported staff with poor personal hygiene - including not washing their hands.
The dossier of reports also revealed 107 hospitals did not have the correct food safety documents and 25 had poor staff training.
Liberal Democrat health spokesman Norman Lamb said the findings were unacceptable.
"These findings paint a shocking picture of hospital food hygiene in this country," he said.
"It is simply unacceptable that such terrible practices are taking place in an environment where hygiene and safety should be paramount."
Mr Lamb called for hygiene standards to be made public via individual institution ratings.
He added: "The worst performers should be named and shamed - while those doing well would stand as an example to drive up standards."
The Food Standards Agency said it would be concerned about "any reports of poor hygiene standards in any catering businesses" but that hygiene was of "paramount importance" when serving food to hospital patients.
"We would be keen to see any information or report that shows significant hygiene problems and will take the matter up with the local authorities involved, whose remit is to inspect and enforce food hygiene regulations within all catering businesses," a spokesman said.
"Where there are problems we will expect the local authority to take appropriate and immediate action."
A Department of Health spokeswoman said the government expected every NHS trust to take their responsibilities for hospital food "very seriously" and that failure to meet hygiene standards was "unacceptable".
Last year, consumer group Which? also reported poor hygiene standards in some UK hospital kitchens.
Which? reviewed hygiene inspection reports for 50 hospitals and found evidence of cockroaches, mice and mouldy cooking equipment.