Revealed: The dishwashing detergents that are 'worse than water'

Consumer group Choice has ranked the best and worst performing dishwashing detergents, claiming some are worse than just using warm water.

Choice pre-soiled tiles with rice starch, bolognaise sauce and egg yolk overnight and then put 30 commercial products to the "scrub test".

The experiment found seven brands were less effective than scrubbing stains with warm water.

The worst performing detergent was Earth Choice dishwashing liquid, scoring just 28 per cent in the scrub and foam tests.

Coles Smart Buy dishwashing liquid and Coles Super Strength Dishwashing Liquid were also in the bottom three.

The Smart Buy scored 29 percent and Super Strength 35 per cent.

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The Choice report said it did the scrub test with each product eight times and averaged the score for consistency.

"The performance score is based on how clean each plate is after reading the result using a spectrophotometer," the report said.

A foam test was also done by putting 4mL of each dishwashing liquid in five litres of warm water and counting the number of plates cleaned until all the foam dissolves.

The top performing detergent was Morning Fresh Ultra Concentrate Ultimate, cleaning 2700 plates per bottle.

Morning Fresh was followed by Kin Kin naturals' Eco Dishwash Liquid and Woolworths Select Shine Super Concentrate Antibacterial.

“Most people would find it shocking to hear that regular tap water and a bit of elbow grease works better than some of the common detergents found at the supermarket,” Choice spokeswoman Stefanie Menezes said in a statement to Yahoo7.

“That’s because the detergents are slippery and can actually lubricate your sponge so it glides off your plate, meaning they don’t work as well when you’re trying to scrub off those tough bolognaise stains from dinner.

"The plates are put through a scrub test, with 90 per cent of the score devoted to how clean your plate comes out.

"The remaining 10 per cent of the overall score is based on how many plates you can wash until the foam runs out.”

Choice said the test's definition of clean means there were no visible food stains or detectable grease on the tile.

In a statement to the Herald Sun, managing director of Earth Choice owner, Natures Organics, said the testing method was “flawed”.

“It is physically impossible for water to clean grease more effectively than when added with Earth Choice dishwashing liquid,” Justin Dowel said.

In a statement to Yahoo7, a Coles spokesperson said customers are advised to return the dishwashing product if they are unhappy with results.

“The Choice testing method does not reflect the way that dishwashing liquid is actually used by customers," the statement said.

"Customer feedback on Coles brand dishwashing liquids has been very positive, and with pricing between 60 and 90 per cent cheaper than proprietary brands, they deliver great value.

"If customers are not 100 per cent happy with any product, we encourage them to return it to their local store for a refund or replacement.”