Hygienic requirements for materials of the hottest

2022-08-20
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Hygienic requirements for the materials used in dairy packaging

at present, dairy products, as a kind of healthy food, have entered thousands of households and become an indispensable food in people's dietary life. The safety and reliability of packaging containers, packaging materials and various exquisite printed patterns, which are inseparable from dairy products, will directly affect the health of consumers

the author believes that the hygienic requirements of dairy packaging focus on two aspects: first, the hygienic requirements of packaging materials themselves; The second is the hygienic requirements of printing ink. These two aspects are described below

hygienic requirements for packaging materials

there are two kinds of dairy packaging forms that are widely circulated in the market, one is the common Tetra Pak packaging, and the other is the composite film bag (commonly known as black-and-white film). Tetra Pak packaging is mainly composed of four or seven layers of pe/paper/aluminum foil/pe; "Composite film bag (black and white film)" is mainly composed of ldpe/lldpe/mpe. The structure and production process of these two kinds of materials are relatively complex, and the solvent residue of the packaging material itself is a problem that can not be ignored. At present, China has not formulated health and environmental protection requirements for dairy packaging materials, and the national standards for food packaging materials and their health indicators are also implemented, such as ny/t general guidelines for green food packaging, gb/t health standards for biaxially oriented polypropylene (BOPP)/low density polyethylene (LDPE) composite films and bags, GB health standards for PVC molded products for food packaging, and gb96, which are expected to be put into production in early 2018; 15000 tons of battery grade lithium carbonate and 2500 tons of industrial grade lithium carbonate are under construction projects, "Hygienic standard for composite food packaging bags", GB "Hygienic standard for polyethylene molded products for food packaging", GB "Hygienic standard for polypropylene molded products for food packaging", GB "Hygienic standard for melamine molded products for food packaging", GB "Hygienic standard for amide epoxy resin coating on the inner wall of food containers", GB "Hygienic standard for polyethylene resin for food packaging" GB hygienic standard for polypropylene resin for food packaging, etc

there are some indicators in China's current packaging national standards that are quite different from the corresponding indicators of foreign related products. For example, according to relevant Japanese laws, the total amount of solvent residues in food packaging materials and printing inks is not greater than 3mg/m2; The total residual amount of a single solvent is required to be no more than 1mg/m2. In China, gb/t requires that the total amount of solvent residue should not be greater than 10mg/m2, and the total amount of single solvent residue should not be greater than 3mg/m2, in which the solvent residue of printing ink has not been considered

hygienic requirements for printing ink

since almost all food packaging materials increased by 170% year-on-year (2) 20% of materials need to be printed with ink, printing ink is closely related to food hygiene. Although the composite membrane bag has high heat resistance, water resistance, oil resistance, chemical reagent resistance and certain barrier and heat sealing properties, due to the limitations of the packaging materials, such as sand holes, relative barrier and relative resistance, soluble heavy metals and residual solvents in the printing ink will migrate to the contents through the printing process. Among them, the indicators that affect the hygienic quality of packaging include the following aspects

1. Soluble heavy metal content

cadmium, lead, mercury, chromium, arsenic and other heavy metals can pose serious harm to the natural environment and human body. For example, chronic low-level exposure to lead can cause changes in human immune function and inhibit the production of antibodies; It can cause mental retardation of children and infants, and even cause convulsions and other serious consequences. Foreign countries have already strictly controlled the content of heavy metals in products in contact with human body. The European community, the United States, Japan and other countries have formulated various relevant regulations and standards, such as European community standards en:1994, en:1997; American Standard ASTM FA, etc. At present, there is no national standard for the limit of heavy metals in inks in China. We recommend the European community standards en:1994, en:1997 and ASTM FA for the detection of packaging products

the author has carried out a large number of tests on some inks using European community standards and found that some of them, especially lead, chromium and cadmium, have high contents. For example, the lead content of composite film printing ink is 0.25 ~ 1000mg/kg, and the lead content of most printing inks is far higher than the limit specified by some European and American countries, which is harmful to human health

2. Solvent residue

China's dairy packaging printing inks are mainly solvent based inks and water-based inks. Due to the late start of water-based inks, and the process problems have not been completely solved, the printing effect for composite film bags is not ideal. Therefore, most enterprises still use solvent based inks for printing. Solvent based inks generally contain a large number of organic solvents, some of which are harmful solvents. Although most of the solvents volatilize after deep processing and forced drying, some solvents remain on the packaging, which will endanger human health. At present, China's standard on solvent based ink solvent residue is only the industry standard qb/t gravure composite plastic film ink, which stipulates that the sum of toluene, xylene, isopropanol, ethyl acetate, butanone, acetone, ethanol and butyl acetate solvent residues is not more than 30mg/m2, and we found that the residue of a single solvent in most inks is more than 10mg/m2

therefore, it is urgent to make detailed and strict regulations and constraints on the solvent residue of printing ink for dairy packaging to ensure the hygiene and safety of packaging

3. Harmful chemicals

the ink used for dairy packaging and printing is a mixture, which contains a certain proportion of additives in addition to Colorants (mainly pigments) and solvents. The United States, Japan and some European countries have formulated corresponding laws, regulations or technical standards for toxic substances, carcinogens, corrosives, sensory substances that are banned or restricted in inks, irritants and toxic reprocesses that are considered by both China 5 mining and Alibaba. Today, with the rapid development of China's economy, corresponding standards or regulations should be issued as soon as possible

detection method of health indicators

1 Detection of soluble heavy metal content

apply an appropriate amount of test ink sample on the glass plate. After it is completely dry, obtain the coating from the glass plate at room temperature by mechanical method and crush it. Finally, obtain a test sample of no less than 100mg through a metal sieve with a pore size of 0.5mm

mix the test sample with 0.07mol/l of an appropriate amount of hydrochloric acid aqueous solution at 37 ± 2 ℃, adjust the pH value to 1.0 ~ 1.5, and continuously stir the mixed solution for 1 hour. After stirring, place it at 37 ± 2 ℃ for 1 hour, and then effectively separate the solids in the mixture as soon as possible, Use atomic absorption spectrophotometer or chemical instrument with equivalent principle to test the content of various soluble heavy metal elements in the solution to be tested

2. Detection of solvent residue in packaging materials

use gas chromatograph or instrument with equivalent principle to prepare standard solvent samples according to the types of solvents actually used in production, and take 0.5 with a microliter syringe μ l、1 μ l、2 μ l、3 μ L and 4 μ L sample, converted to mass. Inject the samples into a clean and dry 500ml triangular bottle sealed with silicone rubber, put them into a constant temperature oven at 80 ± 2 ℃ for 30 minutes, take 1ml of gas from the bottle with a 5ml syringe, and quickly inject it into the chromatograph for determination. Make a standard curve with the total peak area and the corresponding sample quality

cut 0.2m2 sample and quickly cut the sample to 10mm × 30mm fragments are put into a clean 500ml triangular flask preheated at 80 ℃, sealed with a silicone plug, and then sent to a constant temperature oven at 80 ± 2 ℃ for heating for 30 minutes. After that, use a 5ml syringe to take 1ml of gas from the flask and inject it into the chromatograph for determination. Find out the corresponding solvent residue on the standard curve with the total peak area value, and the test results are expressed in mg/m2

3. Detection of ink solvent residue

use gas chromatograph or instrument with equivalent principle to prepare standard solvent according to the solvent type required by the product standard, and use 10% of each solvent μ L the sampler injects 1 into the 300ml infusion bottle through the sealant plug μ L standard solvent, put it into a constant temperature oven at 80 ± 1 ℃ for 20 minutes, and then put it into a constant temperature oven at 50 ± 1 ℃ for more than 20 hours the next day. After taking it out, use a 1ml syringe to extract 0.2, 0.6, 0.8, 1.0ml of gas from the bottle respectively for testing, and make a standard curve

the ink is made into a printing sample on the biaxially stretched polypropylene film, which is suspended for 2 hours, and the sample is cut into 4 strips with a specification of 5cm × 10cm, with a total area of 200cm2, immediately put it into a 300ml infusion bottle, plug the mouth of the bottle, and place it in a constant temperature oven at 80 ± 1 ℃ for 30 minutes. After taking it out, extract the gas with a 1ml syringe, inject it into the chromatograph for determination, and find out the corresponding solvent residue on the standard curve with the peak total area value. The test result is expressed in mg/m2

Yin Shu, China's packaging industry - issue 6, 2006

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