The news revolves around consumer awareness towards the usage of stored men-tsuyu, a type of soy sauce widely used in Japanese cuisine, after opening the bottle. With the broad statement of "must be used within 3 days", concerns have surfaced regarding spoilage and food safety risks due to its ambiguous usage guidelines. The food industry and related authorities are working to address this issue for the sake of public health.

Japan is a society with strong emphasis on food hygiene and safety. There is also reverence for traditional foods like men-tsuyu. Any doubt on food safety, including those specific products, could rapidly escalate into a significant public concern. Hence, this news has sparked debates among consumers, experts, manufacturers, and health authorities, making it a hot topic in Japan.

In comparison to the US or EU, food safety and labeling guidelines are also strictly enforced. Usage guidelines like "best before" and "use by" dates are common. However, the specific focus on a traditional and commonly used product like men-tsuyu in this news piece may not directly correlate to any identical situations in these regions.