Question:
A recent column said potatoes shouldn’t be stored in the fridge. However, the packet of new potatoes I have just bought says on the label to store them in the fridge. Who is right? What is the evidence for determining the best storage location?
Answer:
Great question, and you’re not alone in noticing the confusion. Until recently, advice from food safety authorities cautioned against refrigerating raw potatoes. However, some producers are now recommending the fridge as the ideal place for spuds. Who’s right? As it turns out, both sides have a point, and recent evidence has helped shift the thinking.
For years, consumers were advised to store raw potatoes in a cool, dark and well-ventilated place – but not in the fridge. The worry was that refrigerating raw potatoes increased their sugar content, a process known as “cold-induced sweetening”, which could then lead to higher acrylamide levels forming in the potatoes during cooking. Acrylamide is a problem because it is considered a probable human carcinogen by the International Agency for Research on Cancer.
Acrylamide forms through a natural chemical reaction between sugars and an amino acid called asparagine during cooking. Both ingredients are found in potatoes and other starchy foods such as bread, cereals, crackers and biscuits. When sugar and asparagine are exposed to high heat through frying, baking or roasting, they react and form acrylamide.
The thinking was that by storing potatoes in a dark cupboard rather than the fridge, less sugar would develop in the potato, thereby reducing the amount of acrylamide formed when the potato was later cooked.
However, recent research has shown that the effect of fridge storage on acrylamide formation in cooked potatoes may not be as significant as previously feared, and in some cases, refrigerating potatoes might actually reduce acrylamide levels, depending on the potato variety and cooking method.
For instance, a study funded by the UK’s Waste & Resources Action Programme found storing potatoes in the fridge did not markedly increase sugar levels and therefore the potential for acrylamide formation. The findings were published in 2020 in the Annals of Applied Biology.
Researchers chose two common varieties of tubers, which were assessed at either 18°C or 5°C during a 15-day treatment period. For potatoes stored in fridge conditions (5°C), the sugar levels showed little or no variation over the 15-day period.
This research was reviewed by the UK’s Food Standards Agency, which subsequently changed its consumer advice to state that potatoes could be stored either in the fridge or a cool dark place.
Love Food Hate Waste (a New Zealand and UK initiative) updated its guidance based on this research and concluded that for most households, the fridge at below 5° Celsius is now considered the best place to store raw potatoes. It significantly prolongs shelf life and reduces food waste, with no compelling evidence that it increases health risks when potatoes are later cooked.
Storing potatoes in the fridge helps prevent sprouting and spoilage, which is especially helpful in warm or humid climates.
In New Zealand, where many homes don’t have a cellar or consistently cool pantries, fridge storage is often the most practical option.
It’s still a good idea to minimise acrylamide where possible, particularly if you’re regularly eating fried or roasted potatoes. However, the cooking method has a significantly greater influence on acrylamide levels than the storage location. For example, frying and baking at high temperatures (above 120°C) for extended periods produce more acrylamide than boiling or steaming. Cutting potatoes into larger pieces, soaking them before cooking, and avoiding excessive browning are all simple ways to reduce acrylamide formation.
Email your nutrition questions to listenerlife@aremedia.co.nz
