Eighteen enforcement orders were served on businesses for breaches of food safety legislation last month, the highest number served in any month in a decade.
The Food Safety Authority of Ireland (FSAI) said 12 closure orders and six prohibition orders were served in October on food businesses by environmental health officers or veterinary inspectors.
Four businesses were also successfully prosecuted by the Health Service Executive.
FSAI chief executive Alan Reilly expressed his concern at the "high level" of non-compliance with regulations.
"The inspectors found illegal, unhygienic or unsafe foods, with significant breaches of food safety legislation that put people's health at serious risk," Prof Reilly said.
"There's absolutely no justification for negligence in this area. The legal onus is on food businesses to act responsibly and ensure that the food they serve and sell is safe for consumption.
"This requires putting appropriate food safety management procedures in place and making sure they are adhered to at all times."
Details of all the orders are published at fsai.ie