The most concerning issue for consumers is the release of harmful substances, which has a unified quantitative evaluation standard in the field of food contact materials - transfer testing: by simulating real contact scenarios (food type, temperature, duration), the total amount of substances transferred packaging to food the quality of specific hazardous substances are detected. The results must be below the national standard limit to be considered qualified.

For scenarios such as raw fish slices that are "cold food, contain animal fat, contain water", the industry usually uses water n-hexane/isooctane (simulated oil) as food simulants, conducts migration experiments at refrigeration temperature to test two core indicators.

1. Total migration amount: The total amount of precipitated substances is far below the safety line

The total migration volume measures the total amount of non-volatile substances transferred packaging to food, is the most fundamental safety indicator.

National standard limit: ≤ 10 mg/dm ²;

Actual test results show that compliant food grade BOPS sushi boxes typically have a total migration of only 1-3 mg/dm ² in a simulated refrigerated oil environment, far below the national standard limit, the precipitation level is within a safe range.

This means that in normal usage scenarios, the total amount of substances transferred the box to the raw fish fillet is extremely low will have an impact on food safety.

2. Styrene monomer: characterized by extremely low migration of risk substances

Styrene monomer is a characteristic risk substance of polystyrene materials also the most concerned component by the public. The residual monomers that have been fully polymerized may migrate food during contact, so the national standard has strict limit requirements for them.

National standard limit: Specific migration amount of styrene monomer ≤ 0.05 mg/kg;

Actual level: BOPS boxes produced using new food grade raw materials standardized processes have residual monomers themselves controlled at extremely low levels, the migration amount in cold food scenarios is usually only 1/10 even lower of the limit, completely within the safe range.

Especially for sashimi, it belongs to the low-temperature short-term contact scenario. The lower the temperature the shorter the time, the weaker the molecular migration, the risk is much lower than that of high-temperature long-term contact scenarios. In the conventional scenario of refrigerated packaging consumption within a few hours, the migration of styrene in regular products can be completely ignored.

3. Other risk substances: zero detection/far below the limit

Heavy metals: ≤ 1 mg/kg based on lead, usually detected in compliant products;

Plasticizers Bisphenol A: BOPS production does require the addition of such substances, regular products have been detected, so there is no risk of plasticizers commonly found in plastic packaging;

Aromatic primary amines: The new national standard clearly requires that they should be detected, coloring agents printing inks must meet food contact requirements.