Woolworths has recalled its WBeauty Complete Clarifying Shampoo after additional testing detected Pluralibacter gergoviae, a bacterium capable of contaminating personal care products.

The recall applies to the shampoo sold in 250ml bottles. Woolworths has removed the product from its shelves and asked customers to stop using it.

Customers can return the shampoo to any Woolworths store for a full refund. They do not need to provide a receipt or other proof of purchase.

Woolworths said the contamination was detected after its quality assurance process identified a problem affecting a limited batch and prompted further testing.

Pluralibacter gergoviae is sometimes found in wet manufacturing environments and can survive the standard chemical preservatives used in everyday consumer products. It has been detected in cosmetics and personal care products internationally.

The bacterium presents a low risk to most healthy people. Consumers with weakened immune systems face a greater risk of infection and have been advised to discontinue use immediately.

The recall is the correct response. Once contamination is confirmed, a retailer must remove the product quickly, explain the risk clearly, and make refunds straightforward.

Woolworths has done that without requiring consumers to prove when or where they purchased the shampoo.

The incident nevertheless raises questions for the manufacturer and Woolworths’s quality control system.

An investigation should determine how the bacterium entered the product, whether the contamination occurred during manufacturing or packaging and whether any related products were produced in the same facility.

The results should be used to prevent a recurrence.

Product recalls do not necessarily demonstrate that a company’s entire quality system has failed. Testing systems exist precisely to identify defective products before they cause widespread harm.

The real measure of a retailer is how it responds once a problem is discovered.

Woolworths must now complete the recall, identify the source of the contamination, and provide customers with any further information needed to determine whether their bottles formed part of the affected batch.