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2022-08-02
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Jiangsu Consumer Protection Commission tests the fresh-keeping film and bag

release date: Source: Fubao information Views: 5388 copyright and disclaimer

core tips: how about the safety performance, use performance and cost performance of the fresh-keeping film and bag? Recently, the comparative test results of fresh-keeping film and fresh-keeping bag released by Jiangsu Consumer Protection Commission show that PVC fresh-keeping film will release more chemicals if it comes into contact with greasy food, causing hidden dangers to human health

[China Packaging News] how about the safety performance, use performance and cost performance of fresh-keeping films and bags? Recently, the comparative test results of fresh-keeping film and fresh-keeping bag released by Jiangsu Consumer Protection Commission show that PVC fresh-keeping film will release more chemicals if it comes into contact with greasy food, causing hidden dangers to human health

the samples of this comparative test were purchased by the staff of Jiangsu Consumer Protection Commission from five physical supermarkets in Suzhou and Nanjing, as well as four e-commerce platforms: tmall mall, JD mall, Suning e-commerce and Amazon. Among them, 30 batches of fresh-keeping film are divided into 23 batches of polyethylene (PE), 6 batches of polyvinyl chloride (PVC) and 1 batch of polyvinylidene chloride (PVDC) according to different materials; There are 30 batches of fresh-keeping bags, which are divided into 5 batches of household withdrawable fresh-keeping bags, 21 batches of coiled bags and 4 batches of chain clamping self sealing bags according to different structures. All of them are made of PE

the comparative test sample entrusted Jiangsu Institute of product quality supervision and inspection to test and compare the hygienic performance index (item) and service performance (item) concerned by consumers according to relevant national standards. Health performance indicators include: total migration, potassium permanganate consumption, heavy metals (calculated by Pb), migration of vinyl chloride monomer, epoxy soybean oil, etc. service performance includes: tensile strength, right angle tear strength, self-adhesive, dart impact, sealing strength, barrier performance, etc

6 batches of PVC fresh-keeping film exceeded the standard in total migration amount of contact grease

the index of total migration is to assess the amount of chemical substances that may be separated out when the other end of the fresh-keeping bag is fixed close to the machine body and pressed by hand when it is in contact with water, vinegar, wine, oil and other substances. These substances may be low molecular weight additives or inorganic fillers, such as calcium carbonate, talc powder, etc., which will not only directly affect the color, aroma, taste and other edible quality of food, but also have adverse effects on human health and may even cause a variety of diseases. GB 4806. The national food safety standard plastic materials and products for food contact stipulates that the total migration limit is not greater than 10 mg/dm2. The smaller the check-out value of the migration volume, the higher the security performance

the comparison test results show that when 60 batches of products are exposed to acid simulants and alcohol simulants with concentration less than 20%, the total migration test results meet the national standards. However, when 6 batches of PVC fresh-keeping films were tested for oil simulant, the total migration was mg/dm2. This further confirms that PVC plastic products shall not contact with oily food. If they contact with oily food, more chemicals will be released, causing hidden dangers to human health

3 batches of fresh-keeping bags were damaged

5. Press the upper collet down 15-25mm by hand, and then stabilize 21 of the 30 batches of fresh-keeping bags, of which 3 batches of fresh-keeping bags were torn and damaged during the test. The main reasons for this problem are as follows: the thickness of the fresh-keeping bag is uneven, and it is easy to be damaged after being pulled; The longitudinal tensile strength of the fresh-keeping bag is too large, so it is not easy to break; The point and section cutting is not obvious enough, and the coiled bag is separated from the heat seal during tearing

5 batch fresh-keeping film length is inconsistent with the label

among the 60 batches of samples purchased in this comparative test, the length of PVC fresh-keeping film purchased from e-commerce platform in 5 batches is inconsistent with the length marked on the publicity page, and the actual length of some fresh-keeping films is nearly 40% shorter than that of a small amount. The quantity deviation of fresh-keeping bags shall be within 4% of the nominal value of the package. The nominal brands of the five batches of samples are Qidian, Lvben, meijianan, you + Neng and Jinghui Sichuang

1 batch product standard marking error

in this comparative test, it is found that there are some problems in the labels of fresh-keeping bags and fresh-keeping films: first, the microwave information is not comprehensive, the heating temperature is not marked, and only "microwave oven is applicable"; Most plastic materials have similar properties. Second, the warning information is not comprehensive, and it is not indicated whether they can directly contact food when heated. In addition, there are errors in product standards

pvdc had the best strength and PVC had better self adhesion

strength value includes tensile strength and right angle tear strength. Tensile strength is the tensile force that fresh-keeping film and fresh-keeping bag can bear on the unit cross-sectional area. This item reflects the weight bearing capacity in the actual use process. Right angle tear strength is an indicator of the tear resistance of fresh-keeping film products. The tear strength determines the difficulty of consumers in tearing the fresh-keeping film during use

in this comparative test, it is found that the strength of polyvinylidene chloride (PVDC) is the best, that of polyvinyl chloride (PVC) is the second, and that of polyethylene (PE) is the worst. The right angle tear strength of PE fresh-keeping film is the highest, and that of PVC fresh-keeping film is the second. However, at present, many PE fresh-keeping film manufacturers in the market have launched their own cutting tools (sawtooth) or directly use point break fresh-keeping film for external packaging, which has greatly improved the use experience of consumers

self adhesion refers to the adhesion of the fresh-keeping film itself, which reflects the firmness of the wrapped food in the actual use. In this comparative test, it is found that the self-adhesive of PVC is better, and that of PE is the second

fresh keeping bags are not suitable for carrying

many consumers encounter such a situation that a hole is formed when a box of yogurt is put into the fresh-keeping bag; The seal at the lower part of the fresh-keeping bag leaks after packing food with a fresh-keeping bag or carrying it for a while. Because there is no corresponding national standard for the dart impact and sealing strength of fresh-keeping bag products, the standard of gb/t plastic bags for daily use is used for reference in this comparative test

it is found that the chain clamp self sealing bag is about 0.05mm thick, which is about 5 times that of ordinary household fresh-keeping bags, and the sealing strength exceeds 10N, so it can be used for short-distance food lifting; The thickness of ordinary household fresh-keeping bags is only about 0.01mm, and the sealing strength is about 5N. In the dart impact test, 10 samples of a well-known brand fresh-keeping bag with a high market share were all broken in the dart impact project. Therefore, it is recommended that consumers only use it for the freezing or preservation of a small amount of food at home, or for temporary packaging. It is not recommended to carry it

pe chain clamping self sealing bag has good water vapor barrier performance

one of the biggest uses of fresh-keeping films and bags is that consumers use them to pack fresh vegetables or fruits. They should not only have a certain barrier performance, but also ensure the normal "breathing" of the contained food to achieve the fresh-keeping effect. Barrier performance is divided into water vapor transmission and oxygen transmission

the water vapor barrier performance is mainly to inspect the external water vapor entering the package after the food is packaged, and also to prevent the water inside the package from penetrating out. The results of this comparative test show that in terms of moisturizing performance, PE chain clamping self sealing bag PVDC fresh-keeping film PE fresh-keeping film PVC fresh-keeping film

oxygen is one of the main reasons for the quality decline of many foods during storage. Oxygen will cause oil oxidation and rancidity odor. This comparison test shows that among the oxygen barrier properties, PVDC fresh-keeping film PE chain clamp self sealing bag PVC fresh-keeping film PE fresh-keeping film PE fresh-keeping bag

therefore, when selecting packaging materials for water sensitive foods such as coffee, tea, dried fruits, etc., it is necessary to select chain clamping self sealing bags with good water vapor barrier performance for storage; As for tomatoes, apples, bananas and other fruits and vegetables, because they will release ripening agent (ethylene), they should be put into fresh-keeping bags with good air permeability and moisture retention, and then stored in the refrigerator

consumption warning

Jiangsu Consumer Protection Commission hereby reminds consumers that PVC fresh-keeping film is easy to produce plasticizer and other harmful substances when contacting greasy food, which will affect their health. Consumers should bring their own packaging containers when purchasing non prepackaged food containing grease

in addition, consumers should also pay attention to the following points:

after independent innovation and digestion, and receiving advanced advanced skills

1. Try to choose and buy self-adhesive fresh-keeping film or bag made of PE material, not only pay attention to the price, but also pay attention to the integrity of product labels or instructions

2. It shall be used according to the temperature range specified on the product package. If the food needs to be heated, the fresh-keeping film with strong heat resistance shall be selected, and direct contact with fat food shall be avoided as far as possible

3. Do not reuse the disposable fresh-keeping film, and do not let the film directly contact with food for a long time

4. Do not use microwave oven to heat the fresh-keeping film that is not marked with "can be used in microwave oven"; Note the fresh-keeping film that can be heated by microwave, and pay attention to prevent the use temperature from being too high due to improper heating method, which may lead to changes in chemical or physical properties

5. As some fruit stores, delis or supermarkets will use PVC fresh-keeping film for food packaging, consumers are advised to take out cooked food containing oil in time and do not bring fresh-keeping film for heating

6. For vegetables and fruits that release ripening agent (ethylene), such as tomatoes and apples, it is recommended to put them in fresh-keeping bags with good air permeability and moisture retention, and then put them in the refrigerator for storage; Moreover, PVDC fresh-keeping film has good moisturizing performance, which can appropriately ensure the fresh-keeping period of fruits and vegetables

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