In the gutter oil incident reported by reporter Xiang Li, it was not clearly pointed out that gutter oil was a certain brand of soybean oil. Waste cooking oil is a kind of inferior edible oil, which is usually extracted from waste cooking oil produced in catering industry and food processing. These waste oils come from various sources, including restaurants, canteens and food processing plants. The reason why gutter oil is widely concerned is that it is extremely harmful to human health.