A spokeswoman for LeaderBrands said all supermarkets, organisations and the Ministry for Primary Industries were contacted soon after the contamination was discovered.
Supermarkets were advised to put up warning signs.
"Everything that could have been done was done," she said.
Foodstuffs, which operates New World, Pak'nSave and Four Square, was alerted late on Thursday evening.
Head of External Relations Antoinette Laird said stores were instructed to remove the recalled products from sale and signage would be put up in stores as soon as it was available.
LeaderBrand chief executive Richard Burke said he was confident no products other than the Caeser Salad were affected.
He said the company took health and safety very seriously, and expected to be able to resume supply soon.
Customers should either dump the salads or take them to the place of purchase for a refund, he said.
Toi Te Ora Public Health Service medical officer Phil Shoemack said the service had been notified of one case of listeria this year, in mid-January.
"Listeria can cause anything from a mild tummy upset to vomiting, diarrhoea and cramps to severe infection which causes septicaemia - blood poisoning," Dr Shoemack said.
People with symptoms at the lower end should see their GP while those severely unwell would need to be admitted to the emergency department.
"Pregnant women are at particular risk and listeria is a recognised cause of fetal death. It's why women are given clear advice to stay away from delicatessen foods like soft cheeses, shellfish, fermented meats because of their association with listeria."
Dr Shoemack said it was a relatively uncommon infection.
Across the coastal Bay of Plenty - form Waihi to Cape Runaway - there were four cases notified to Toi Te Ora during 2016.
Affected brands:
LeaderBrand Caesar Salad (tested positive)
LeaderBrand Classic Salads
Fresh Plus Salads
Value Bag Salads
100% Fresh Salads
Some Pam's Fresh Express Salads
- Pams Fresh Express Italian Salad 250g
-Pams Fresh Express Crispy Salad 250g
-Pams Fresh Express Herbslaw 450g
-Pams Fresh Express Coleslaw Dressed 450g
-Pams Fresh Express Mesclun Salad 500g
-Pams Fresh Express Farmhouse Slaw Dressed 450g