Consumer Focus Wales says more than 60 schools, nursing homes and hospitals in Wales have sub-standard food hygiene and is calling for full inspection reports to be made available to the public in order to protect vulnerable groups.
BBC News reports the watchdog has published a map showing public institutions with ratings below the satisfactory score.
Maria Battle, senior director of Consumer Focus Wales, called for the assembly government to use its new direct powers to ensure food hygiene ratings were displayed at business premises.
"It is not acceptable that there are publicly-funded institutions, such as hospitals and schools, serving food to vulnerable people despite failing to meet statutory requirements for food hygiene. The greatest tool for improving food hygiene is openness to public scrutiny by making businesses display their food hygiene ratings on the premises. What greater incentive for food producers than knowing their rating will be public and their failings will no longer be hidden?"
A spokesperson for the Welsh Local Government Agency said, "The idea behind the food hygiene rating system is to promote consumer choice and drive up standards in food businesses. A business with a poor rating is generally one that is found on inspection to need to improve standards. However, the reason for a low score could be that the business does not currently have a written procedure for food hygiene. Whilst the business premises could be spotless, without this written supporting document they could not be scored above a one-star rating. It is important to note that those premises with low ratings are most likely to be in the process of improving."
Food hygiene ratings can vary from zero (urgent improvement necessary) to five (very good).
Sharon Mills, the mother of Mason Jones, the schoolboy from Deri near Bargoed who died in the 2005 E. coli outbreak after eating infected meat, said it was "diabolical" that hygiene was not up to scratch at premises serving vulnerable people.