An Adelaide nursing home has admitted there is "room for improvement" in its food service after a photo of a Christmas meal allegedly given to a resident sparked an online backlash.

Key points: The meal of baked beans and mashed potato has been labelled "disgusting" and "disgraceful" on social media

The meal of baked beans and mashed potato has been labelled "disgusting" and "disgraceful" on social media The Vales nursing home is run by All Care Aged Care, which says it is committed to high food standards

The Vales nursing home is run by All Care Aged Care, which says it is committed to high food standards SA MP Nat Cook says one woman was reduced to tears after receiving the "slopped-out" meal

The image of mashed potato and baked beans was shared on social media by South Australian MP Nat Cook, who said it was sent to her by a relative of a resident at The Vales aged care facility at Morphett Vale.

Ms Cook said the "slopped-out beans with a couple of scoops of mashed potato" was well short of expectations, especially on Christmas Day.

She said the resident who received it was brought to tears.

"I'm told that other residents were also having the same lunch and I just don't think that's good enough on Christmas Day, for people who clearly haven't got the opportunity to go out with family," she said.

Ms Cook shared the image on Twitter with Maggie Beer, who recently spoke out at the Royal Commission into Aged Care.

"I think we've got a broader issue being highlighted again around nursing homes," Ms Cook said.

"Maggie Beer has been pushing this in the media for the past few years and providing education sessions around the provision of nutrition for older people."

All Care Aged Care — which runs the facility in Adelaide's south — has defended its Christmas lunch service, saying the baked beans were not part of the day's main meal but were served later in the day.

Ms Cook drew attention to the meal after it was shared with her. ( ABC News: Nick Harmsen )

However, chief executive Neil Pahuja conceded the meal in question appeared to be below the expectations of residents and their families.

"That image looked poorly presented, I'm sure it didn't leave the kitchen like that, but there is certainly room for improvement in serving baked beans with cheesy mash," he said.

"Baked beans could have been put in a container where the liquid doesn't run, it could have been presented much better for sure.

"At the same time, the main meal is the lunch meal and enormous lengths are gone to, to present meals really well all of the time. If there has been any lapse here, it is something we will improve upon."

Mr Pahuja said 105 of the 170 residents selected the mash and baked beans — but more than 10 per cent of those who asked for it opted not to eat it once it arrived.

"Of those 105, 14 people decided they didn't want it and requested salads and sandwiches, which they received," he said.

Meal labelled 'revolting', 'disgusting'

The photo was shared on social media, prompting outrage from Twitter and Facebook users.

"Revolting. People fed by charity lunches and prisons dined on better fare. This is slop," one Twitter use wrote.

"What if you don't like beans? Is this a P.O.W. camp?" another said, while others labelled it "horrible", "disgusting" and "utterly disgraceful".

The Vales at Morphett Vale accommodates about 170 residents. ( All Care Aged Care )

In a response posted on Facebook, All Care Aged Care again admitted the meal was "very poorly presented".

But it also accompanied the comment with several photos showing what it said were more "typical" examples of "Christmas lunch served in our home".

"We will definitely investigate if the posted image was served as an evening meal alternative and immediately ensure such meals, even as a lighter meal, are served in a far more appetising way," it said.

"We are monitoring the matter closely to ensure no lack in presentation or quality in food occurs at any stage."

The facility said it served about 185,000 meals a year and expected "all to be of a high standard".

"Please also note there is unlimited food and beverages available at breakfast, morning tea, lunch, afternoon tea and dinner," it said.

All Care Aged Care said this was a much more typical example of Christmas lunch at The Vales. ( All Care Aged Care )

Mr Pahuja said The Vales was "one of the few facilities which produces all of our food on-site".

"There are projects which we have underway which look at how we can improve things from a presentation point of view; our menus are reviewed by dietitians," he said.

Last year, the operators of the Royal Adelaide Hospital came under fire over the delivery of substandard food to patients.