When I batch cook I fill portions of hot food into glass jars with screw lids and keep them in the fridge. (Those glass jars contained yogurt when I bought them, when I need more I buy more yogurt and eat it)

Each jar is 1/2l so a good size for one portion and I only open them when I take them out of the fridge for usage. By filling hot, keeping cool and not opening them (so introducing only few microorganisms) they stay OK for at least a week.