Aarron Ralston bought multiple packs of the supermarket giant's home-brand tropical juice from the Waverley Gardens store in Victoria on Saturday, believing they were a good option for his daughter after seeing the 5-star health rating.
"We always buy going off the ratings so to give our daughters the most healthy food and drink," he told Yahoo News.
But the 38-year-old was confused when he noticed one of the boxes had a completely different rating while unpacking his groceries.
"We were and still are shocked to find the 2.5-star - that's a huge drop and we wouldn't buy that for our family."
The Springvale resident unleashed online, posting a complaint directly to Woolworths' Facebook page.
"So which is correct. 2.5 star or 5 star. We brought a few packs of these assuming good for our daughter being 5 star but when checked 1 pack says 2.5 others say 5," he wrote.
The Health Star Rating system was rolled out in 2014 after being developed by Australian federal and state governments to help consumers make healthier choices.
It provides a rating from a half to five stars on the front of the pack - the more stars, the healthier choice.
The aim is to make it easy for customers to compare the nutrition of similar packaged products.
Woolies responds to different ratings
A spokesperson for Woolworths told Yahoo News its home-brand tropical juice had been given a new lower rating last year following changes to the way they are calculated and the higher-rated box was from an old batch.
"We display the Health Star Rating on a wide range of Woolworths branded products to help customers make informed choices," the spokesperson said.
"Following a review last year, the Federal Government has changed the way Health Star Ratings are calculated for certain products, including fruit juice.
"The change includes a greater focus on sugar, including natural sugars, and has resulted in lower ratings for many fruit juices.
"We've recently updated our own brand juice labels to reflect the new ratings, however there may still be products available in the old packaging as we sell through it."
Customer considers boycotting supermarket giant
Mr Ralston said he and his wife have now lost faith in the health rating system, questioning the recent changes.
"How can they now change it to be unhealthy after showing it to be a good choice?" he questioned.
"Both my wife and I are not happy and feel very misled. How can we trust the health ratings at all now?
"We will be taking them all back and don't know if we will shop there anymore as we have no trust in the products and feel lied to."
Under the new methodology, non-dairy beverages including fruit juices are graded using a new calculator that considers only energy, sugar (including naturally occurring sugar in fruit) and the fruit, vegetable, nut and legume content of a product.
The Government has provided manufacturers with a two-year transition period up until November 2022 to update their Health Star Rating labels in line with the new system
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