In the photo, the lunchbox can be seen packed with an apple, sliced cucumber, a vanilla yoghurt pouch, pretzels and a ham and cheese croissant.
While some users were curious as to how the mum managed to keep the food fresh, others slammed her for not making time to pack her children's lunches each day.
'No matter what I have on each day I still pack their sandwiches that morning,' one wrote.
'I often get other stuff ready the night before never their sandwiches,' commented another.
'And as for judging I don't think you should judge my time either... Last year I was working 11 hours some days then on top of that feeding animals for an hour each morning and afternoon but still managed to pack lunches each morning'.
'I wouldn't eat three-day old sandwiches so wouldn't expect the kids to eat it,' she added.
However, the time-savvy mum wasn't afraid to hit back at others who criticised her choices, claiming she'd never had a complaint from her kids.
'I eat a three-day old sandwich, my girls never complain and I always check, please don't be so quick to judge,' she clapped back.
'I feel some of these people are under the impression I make my child eat food that doesn't stay good!' she wrote.
Others were quick to leap to the woman's defence, claiming that many restaurants often prepare food days in advance before it's served to customers.