Qingdao Platinum Packaging Technology Co., Ltd. is a manufacturing enterprise specializing in plastic flexible packaging, encompassing the research and development of new plastic materials, printing, laminating, slitting, bag-making, and related R&D. The company’s production base is located in the Jiaobei Industrial Park, Jiaozhou City, Qingdao, while its business operations and R&D center are situated in the Shinan District of Qingdao. With many years of experience, the company produces high‑quality plastic flexible packaging materials and comprehensive packaging solutions. Its main product lines include: laminated plastic packaging bags, color‑printed packaging bags, food‑grade packaging bags, vacuum‑sealed bags, retort pouches, low‑temperature frozen‑food bags, cat litter bags, and rolls of automatic packaging films for food and medical applications; as well as transfer printing films, warning tapes, flag‑type tapes, bird‑repellent tapes, and cable ties for air conditioners, among others.

　　As people’s needs continue to evolve, Plastic packaging bag The materials and colors of plastic packaging bags are becoming increasingly diverse. But does the quality of these bags really depend on their color? And how can we better assess the quality of plastic packaging bags?

　　1. First, check whether the plastic bag bears the “for food use” label. This label is typically printed on the front of the bag in a prominent location. Next, examine the color: colored plastic bags usually contain recycled materials from waste plastics and should not be used to package food.

　　For example, some black plastic bags used in vegetable markets to hold fish, shrimp, and other seafood or meat were originally intended for garbage; consumers should avoid using them. Check the bag for impurities: hold it up to sunlight or a light source and look for dark spots or tears. Bags with visible impurities are almost certainly made from recycled waste plastics.

　　2. Smell the plastic bag to check for any unusual odors that might be unpleasant. A合格 (qualified) plastic bag should be odorless, whereas an不合格 (unqualified) one, due to the use of additives, may emit various smells.

　　3. Qualified plastic bags have adequate strength and do not tear easily; in contrast, substandard bags often contain impurities, resulting in poor strength and a tendency to rupture.

　　4. A合格 plastic bag will produce a crisp, clear sound when shaken; an不合格 plastic bag, by contrast, typically emits a dull, buzzing noise.

　　5. Place the plastic bag in water and press it to the bottom with your hand. After a short while, the bag that floats to the surface is non‑toxic, while the one that remains at the bottom is toxic.

　　6. Run your hand over the surface of the plastic bag: if it feels very smooth, it is non‑toxic. If the color appears cloudy and the surface feels sticky or rough to the touch, it is toxic.

　　7. Combustion: Cut a small corner from the plastic bag and hold it over a flame. A non‑toxic bag will ignite readily, continue burning after being removed from the flame, produce a yellow flame, and melt into droplets that drip like wax, emitting a paraffin‑like odor. A toxic bag, by contrast, is difficult to ignite; when burned, it produces a green flame and gives off a pungent, irritating odor.

　　Use plastic bags sparingly for hot or oily foods. Of course, when you can’t be sure whether a plastic bag is safe, avoiding its use to hold extremely hot or fatty foods is one way to minimize potential risks. Unsafe plastic bags often contain harmful substances such as dyes and heavy metals.

　　The fats and oils found in oily foods such as meat, fish, and fried dough sticks actually act as solvents, causing harmful substances to leach out of plastic bags. Meanwhile, high temperatures can soften the plastic, further promoting the release of these harmful compounds and potentially leading to poisoning. Therefore, storing vegetables at room temperature or frozen foods in plastic bags is relatively safer. Of course, it’s best to avoid using plastic bags for food altogether. When shopping for groceries, bring your own basket or cloth bag; if you must use a plastic bag, remove the food from it as soon as you get home.

　　That concludes today’s presentation. For more information, please visit our official website.