A single busy burger outlet can use close to 50 litres of cooking oil in a day. That amounts to nearly 1,500 litres a month from just one establishment. Multiply that with the thousands of restaurants and street vendors operating across cities like Chennai, and the volume of used cooking oil generated every month becomes staggering. The larger and more pressing question is not how much oil is used, but where it goes after the last batch of French fries is served.
For years, the fate of Used Cooking Oil (UCO) has posed a dual threat. When reused repeatedly for deep frying, oil undergoes significant chemical deterioration. At frying temperatures ranging between 170-190°C, oils are exposed to oxygen and moisture from food, triggering oxidation, hydrolysis, and polymerisation. These reactions alter the oil’s fatty acid profile. Beneficial Polyunsaturated Fatty Acids (PUFAs), which are naturally present in many vegetable oils, degrade under high heat. Simultaneously, harmful compounds such as trans fats and Total Polar Compounds (TPC) increase.
Scientific studies in food chemistry and nutrition research have consistently shown that repeatedly heated oil produces lipid peroxides, aldehydes, and other oxidative by-products. These compounds are associated with elevated LDL (bad cholesterol), higher triglyceride levels, increased oxidative stress, and systemic inflammation. Long-term exposure has been linked to a greater risk of cardiovascular disease, insulin resistance, and liver dysfunction. In simpler terms, reheated oil is not merely a culinary compromise, it is a metabolic hazard.
On the other hand, discarding oil irresponsibly creates environmental consequences. When poured into drains, used oil solidifies and combines with other waste to form massive blockages known as “fatbergs”. These clog sewage systems, damage municipal infrastructure and contaminate water bodies. Improper disposal into soil can also affect groundwater quality and aquatic ecosystems.
Recognising this growing public health and environmental issue, the Food Safety and Standards Authority of India (FSSAI) launched the Repurpose Used Cooking Oil (RUCO) initiative in March 2019.
Under RUCO, food business operators are encouraged to monitor the quality of their cooking oil, particularly ensuring that TPC levels do not exceed 25 per cent, the safety threshold set by FSSAI. Once oil crosses this limit, it is no longer considered safe for human consumption. Instead of being discarded or illegally resold, it is collected by authorised agencies and sent to biodiesel manufacturers. The collected oil is then converted into biodiesel, a cleaner-burning, renewable fuel alternative. This approach contributes to sustainable energy production.
From a public health perspective, RUCO reduces the population’s exposure to oxidised fats and trans fats that contribute to cardiometabolic diseases. By formalising collection and ensuring traceability, the initiative closes a dangerous loophole where degraded oil could otherwise be sold at lower prices to smaller vendors and reintroduced into circulation. For cities with vibrant street food cultures, such regulation is protective.
RUCO represents a shift toward a circular economy in the food sector, transforming a waste product into a valuable resource. It underscores a broader truth: nutrition does not end at ingredient selection. It extends to how food is prepared, monitored, and responsibly managed. Safer frying practices, regulated disposal, and sustainable repurposing, together create a system that protects both public health and the planet.
As more food businesses register and comply, initiatives like RUCO have the potential to redefine urban food safety standards. In doing so, they remind us that the future of nutrition lies not just in what we eat, but in the systems that support it.