Restaurants, retailers and takeaways in Carlow, Cork, Dublin, Galway, Tipperary and Wexford were among those closed
11 food businesses were served with closure orders last month, according to the Food Safety Authority (FSAI).
Business in Carlow, Cork, Dublin, Galway, Tipperary and Wexford were among those closed.
The FSAI says three closure orders were served under the FSAI Act 1998:
Eight closure orders, meanwhile, were served under the EC (Official Control of Foodstuffs) regulations:
A prohibition order was also served under the FSAI Act, 1998 on Golden Beach supermarket, 137 Parnell Street, Dublin 1.
The FSAI says reasons for closure of individual businesses included dead mice found in a production area, a 'significant' cockroach infestation, and mould growth in a kitchen.
FSAI Chief Executive Dr Pamela Byrne said it is "extremely disappointing" to see that May is the highest month so far this year for closure orders.
She said: "There are simply no excuses for putting consumers' health at risk through sub-standard food safety and hygiene practices.
"Summer is a busy time of year for food businesses and systems must be put in place to cope with the increase in customers and at a time when outside temperatures can be a lot higher. Food bacteria can multiply quickly in warm weather and food businesses must ensure food is stored at correct temperatures."