Using leftover kneaded flour stored overnight in the refrigerator is safe and nutritionally similar to fresh flour.

FACT:  

Leftover kneaded dough can pose health risks if stored overnight, as it may promote bacterial and fungal growth. Experts recommend using fresh dough and, if storing briefly, keeping it in an airtight container for no more than 2–3 hours.

Leftover kneaded flour is a familiar sight in most Indian kitchens, whether it’s to save time for the next morning’s breakfast or because the measurements went a little off during dinner prep. But a viral Instagram reel by dietician Bhawesh Gupta has prompted many to wonder if using this stored dough the next day is actually safe.

Gupta, who has 7.2 lakh followers on Instagram, appears in the reel addressing a common household habit –  keeping leftover kneaded flour in the refrigerator overnight. “In our homes, we keep leftover flour in the fridge overnight and use it again the next day. But have you ever thought,  is it really safe and healthy to eat this leftover flour?” he asks in the video.

The dietician explains that flour is a high-moisture, carbohydrate-rich food, making it a perfect environment for bacterial and fungal growth, especially when stored at room temperature. “This growth is even faster at room temperature,” he cautions.

However, Gupta adds that storing the dough at 4 degrees Celsius in the fridge, where humidity is low, significantly slows down microbial growth. Addressing a common concern about nutrient loss, he clarifies that while some temperature-sensitive nutrients such as vitamin C, folate, and polyphenols may slightly decrease, “overall, nutritionally, there is not much difference between stored flour and fresh flour.”

He concludes that for those who are working professionals or live alone, storing the dough overnight in an airtight container in the refrigerator is safe and convenient. “You can store the flour in the fridge without fear and use it for cooking the next day,” Gupta advises.

The reel, which strikes a reassuring and practical tone, has resonated widely online, garnering over 3 lakh views, 14,000 likes, and more than 2,600 shares – as people debate whether leftover dough is truly safe to eat or better left fresh.

Is it safe to use leftover kneaded dough? 

The safety of leftover dough depends on how it is made and stored. Flour itself varies in shelf life based on its level of processing and the source ingredient, such as wheat, almond, or arrowroot. For example, white all-purpose flour tends to stay fresh longer than whole-wheat flour because it is highly refined, with the bran and germ removed, leaving only the starchy endosperm.

Whole-wheat flour retains the bran and germ, which are rich in oils and more prone to spoilage when exposed to light, moisture, or air. These oils can turn rancid, resulting in an unpleasant taste and odour.

Similarly, gluten-free flours like almond or coconut flour, which are high in natural oils, can spoil faster than refined white flour. Additionally, according to a 2017 review, gluten-free all-purpose flour, which typically combines several nut- or root-based flours, may be more vulnerable to mould due to its high moisture content.

Rancid flour undergoes chemical changes that alter its structure, forming compounds that taste unpleasant but are not known to be toxic in small amounts. However, flour contaminated with mould can be dangerous. Some moulds produce mycotoxins, which are harmful chemicals that can cause nausea, vomiting, and diarrhea, and may lead to serious health issues like cancer and liver disease when consumed over time. Therefore, if leftover dough or flour smells odd, tastes bitter, or shows visible mould, it should be discarded immediately.

Storage plays a crucial role in maintaining the quality of flour and dough. According to the United States Department of Agriculture (USDA), flour is considered “shelf-stable”. This means that it can be stored safely at room temperature if kept in an airtight container in a cool, dry place. Refrigeration or freezing can further extend its freshness.

All-purpose flour can last six to eight months at room temperature, about a year in the refrigerator, and up to two years when frozen. When storing in the fridge or freezer, it is important to seal it tightly to prevent moisture and mould growth. Before use, refrigerated or frozen flour should be brought back to room temperature to avoid clumping.

A 2015 study conducted in Babylon province examined mould contamination in local and imported wheat flour samples. It identified common genera like Aspergillus, Penicillium, and Fusarium, and found a strong positive link between moisture levels and mould growth.

The results of the study showed that “differed species and genera association of mould in wheat flour after three months storage at two temperature (5 and 30 ºC). The results indicated that stored at temperature 5 ºC decrease the population and types of moulds on wheat flour.”

Commenting on the claims, Fauziya Ansari, Dietician at Apollo Spectra Hospitals, Mumbai, advises caution. She explains that “leftover kneaded dough can become a breeding ground for bacteria and fungi if left at room temperature for too long,” as its high moisture and starch content creates an ideal environment for microbial growth, which can lead to spoilage and foodborne illness.

She points out that there is no solid evidence showing that refrigeration at 4°C makes overnight dough significantly safer. “It is better to use fresh dough instead of storing it overnight and using it the next day,” she advises. While refrigeration may help preserve most vitamins, minerals, and freshness, sensitive nutrients like vitamin C, folate, and some antioxidants can be reduced.

Ansari also notes that refrigeration or freezing may alter the dough’s texture. “The gluten structure can tighten or become softer, depending on how long it’s stored,” she says, adding that this may affect the final bread or chapati quality.

She emphasises the potential health risks of consuming stored dough. “Consuming it could lead to food poisoning, stomach upset, or other digestive issues. It is not at all a good idea to store leftover kneaded dough overnight. Take charge of your health and eat freshly prepared food, always,” she stresses.

For short-term storage, she recommends a maximum of 2–3 hours and proper handling. “Store leftover dough in an airtight container and refrigerate it within an hour of kneading to prevent bacterial or fungal growth. Use clean utensils and surfaces, and discard the dough if it smells sour or shows discolouration or any other changes. Be attentive when it comes to your health,” she insists.