rats in supermarkets

What’s with all the supermarket rats and mice?


mouse extermination

by Ripu Bhatia

Originally published in 

February 15, 2024

Rodents have been sighted in public areas of two supermarkets.

A pest control expert says high temperatures can cause rat populations to increase and supermarkets are challenging to protect. New Zealand Food Safety has launched an independent review into Woolworths’ pest-management processes.
High temperatures are contributing to recent rodent incidents and supermarkets are difficult to protect, a pest control expert says.

The comments come after a mouse was caught on camera in the deli of Christchurch’s Countdown Eastgate last week and rat issues have caused Countdown Dunedin South to remain closed since last Friday.

New Zealand Food Safety has launched an independent review into Woolworths’ pest-management processes after several rodent incidents.

The logistics of protecting supermarkets from rodents is challenging, an expert says.

Hotter temperatures could be contributing to the problem.

Key players

Woolworths is a supermarket chain based in Australia. Its New Zealand stores are under review following several rat incidents in recent days.

New Zealand Food Safety is the government body responsible for food safety and has launched the review which will be conducted independently.

Owen Stobart is a pest control expert and the director ACES Pest Control.

A climate impact?

Stobart said high temperatures produce more rats and pests in general.

New Zealand is experiencing an El Niño summer which is when trade winds cause ocean water in the central topical Pacific to warm above average.

Climate scientists determined 2023 was the country’s second hottest year on record, and high temperatures have been recorded across the country over the summer.


El Nino brings the predominant north westerly flow from Australia which brings hot dry winds, Stobart said.

So what happens with the higher temperatures and the dry areas? It’s just more favourable, not just for rats, but for all pests.

Stobart said supermarkets also present a challenge for pest controllers for a number of reasons.

With rodents and entry points, it's one of the very important things you need to control to stop them coming in, he said.

But if you've got a supermarket running 24 hours, seven days a week and the doors are wide open at two in the morning when rats are active, then they can sometimes just come in.


How to get rid of rats?

Stobart said another issue was that supermarkets are a source of food.

The main way of controlling rats in the pest industry in New Zealand and around the world is to use baits inside stations, he said.

The problem is if you've got peanuts or you've got delicious pieces of chocolate in packets that rats can easily access then the bait isn't going to work.

Supermarkets are essentially a nightmare if you get the situation where rats have got inside and they've got established.

Why it matters

New Zealand Food Safety deputy director-general Vincent Arbuckle said as rodents naturally find their way onto sites, it’s important that food businesses have strong pest-management practices in place to deal with them,” he said.

Rats can contaminate foods and surfaces and should not be around food. For example, they can spread disease causing-organisms like salmonella.

Arbuckle said all food business are required to ensure the food they sell is safe and suitable for customers’ consumption, and this includes pest-management requirements.

As part of this process, food businesses are registered and regularly checked by an independent verifier, he said.

The verifier will check there are systems in place to ensure pests cannot enter food businesses and the pests are managed if they manage to do so.

- Stuff