Don’t mope about mould: How to avoid mouldy food

Lidl in the afternoon is hectic and as students, the last thing we want to do is waste our time frantically scanning the aisles in an attempt to restock our moulding vegetables. Your flatmate texts you saying they’ve got spares, but when you get home you realise the onion you were counting on is mouldy. Now you’re hangry, and there is absolutely nothing worse. So why does your weekly shop seem to go mouldy after just a few days, and what can you do to stop this?

Why does food go mouldy?

Mould occurs when small cells in the air, known as spores, land on your food. In order to grow, they need suitable temperatures, air quality, water, and food. The onions in your cupboard are the perfect home for these spores, supplying all the conditions needed. Once they land on your food, the small branches on the spores produce roots deep within, quickly replicating so that mould begins to grow.

Moulds are not your only enemy as a student. It is also rather annoying when your fruit turns brown, even though you only bought it yesterday. This is actually a completely different problem, caused by an enzyme called polyphenol oxidase (PPO). When oxygen is present, phenolic compounds – a type of chemical produced by plants – are turned into quinones by PPO. Quinones are a type of pigment found in plants, animals, bacteria and fungi which can react with the melanin found within fruit, causing the fruit to turn brown.

How to keep your food fresh and save yourself money

Moulding and browning are bound to happen eventually, but there are some easy tricks which can help stop it from happening so quickly, saving you time and money. Standard practice, as advised by the US Food Safety and Inspection Agency, is to keep your food covered and use leftovers within three to four days.

However, from asking around and searching through social media, I’ve found some neat tricks to keep your food lasting that little bit longer:

1. Keep your halved avocado next to half an onion. This will keep it from browning for a few extra days, as the onion releases sulphur which stops the oxidation reaction.
2. Store your jars, like pesto, in the fridge upside down. The oil then acts as a seal, reducing the air available for the mould to grow.
3. Keep your bananas away from other fruit. Bananas release a gas called ethene, which breaks down the cell walls of other fruits it is  next to. Molecules called starches are turned to sugars which decreases the acidity of the fruit. This speeds up the browning and moulding of the fruit.
4. Store your bananas with cling film wrapped round the stem. This is supposed to reduce the ethene given off which will slow down browning
5. Keep your onions and potatoes away from each other. Onions also release ethene, causing your potatoes to go brown or start sprouting!