Reusing Cooking Oils

Introduction

It is no secret that deep  frying is a key step for your tonkatsu or goreng pisang to have a crispy and flavourful texture. It is also common for cooking oil to be reused several times before being disposed. How then, can cooking oil be reused safely?

What are the potential food safety risks in reusing cooking oils?

During frying, cooking oil goes through chemical reactions, which results in darker and thicker oil. Foam and smoke are also formed.

When oils are heated at high temperatures repeatedly and for a long time, especially for deep-frying (typically ranging from 177 to 232 °C), the organic matter within breaks down more quickly. This decreases the oil’s smoke point (the temperature oil starts to smoke and burn) and forms compounds that are potentially harmful to health. These compounds include polycyclic aromatic hydrocarbons and aldehydes which, when consumed, increases the risk of cancer and cardiovascular diseases. Consequently, this presents health risks and results in fried foods that are less tasty, flavorful, and aromatic. 

What can consumers and food business operators do?

To reduce exposure to these harmful compounds, you can consider the following tips:

• Replace cooking oil as frequently as possible.
• Replace cooking oil when it changes colour, develops an unusual odour, begins to smoke, or starts to foam.
• Avoid using cooking oils rich in polyunsaturated fats for high-temperature cooking as they are unstable and degrade under intense heat.
• Heat the oil slowly. If reusing oil, top up with fresh oil to an appropriate level when the oil is near frying temperature.
• Strain used cooking oil through a cloth or sieve before reusing it.
• Store used cooking oil in a sealed, light-proof container to reduce its exposure to light and air.
• Consume fried food in moderation.

References

• “How to choose Cooking Oil?” | HealthHub
• “Can oil be reused safely?” | USDA