Research Progress of Food Packaging Contaminants (I)

PVC packaging paper contains 14% to 38% of plasticizers. Most of these plasticizers are environmental endocrine disruptors (EEDs). They can change the normal function of the endocrine system and can damage the end organs or Their offspring have a negative impact. These plasticizers mainly enter foods through food packaging materials. Neonatal and developmental organs are most sensitive to EEDs because the amount of contamination of breastmilk from breast milk is approximately 10 to 20 times the average adult level. In the first year of life, infants will receive the total amount of their life. 10%; Changes in hormonal function can lead to a series of adverse effects, such effects can be macroscopic or subtle, functional or structural, and many effects are undetectable in the near future, these potential effects Population, sex, age, dose, and duration of exposure vary. EEDs are highly fat-soluble and not water-soluble, contaminating fish, meat, eggs and dairy products. It can be detected in the body's adipose tissue, blood, and breast milk. In addition, pregnant women are also sensitive people because their exposure directly leads to the baby's exposure.

This article focuses on several environmental endocrine pollutants that are closely related to food and have not received sufficient attention in China.

1 Bisphenol A (BPA)

Biphenol A (biphenol A, abbreviated as BPA) is an additive for epoxy resins and polycarbonate plastics. The resulting plastic products are used for the packaging of foods and beverages. The resin products are widely used for metal coatings including food cans and bottle caps. And water supply pipe. Bisphenol A is also included in the dental polymer materials.

Low levels of bisphenol A can reduce the number of spermatozoa, increase the incidence of hormone-related cancers, such as breast, testicular, and prostate cancers, and cause congenital defects in the reproductive system (non-hereditary testicular cancer) and hormone-related diseases. Such as girls adolescence ahead of schedule. Even at extremely low concentrations, BPA can affect the proportion of male and female frogs, resulting in the sterilization of snails. Due to the complexity of ecosystems, the impact of BPA on other species is still unknown, and this is the main problem for humans.

Fred vom Saal and Wade Welshons started the alarm early in 1997 because their research team found that even a very low dose of BPA can affect health. If a male mouse is exposed to a very low dose of BPA in the uterus, the weight of the prostate is significantly increased after birth and the daily sperm production is reduced. Moreover, low-dose BPA causes health risks more than high-dose. Later, scientists in the United States and Germany also found similar results and reported the same health effects one after another.

Now, a consensus has been reached on this issue that BPA can also pose health risks at low doses, including the female reproductive system, breast, testis, sperm production, and behavioral effects.

1.1 Production

Industrial production requires a large amount of BPA. The more developed the industry, the greater the amount of BPA needed, and the greater the potential safety hazards to humans. The domestic output is still very small, and the proportion of total production in the world is minimal. However, due to the air, the movement of water bodies, the circulation of commodities, and other issues, the pollution caused by other countries will migrate to our country. The pollution problem is not optimistic.

1.2 Uses

The annual consumption of BPA in the European market in 1997/98 alone was 640,000 tons, and it is reported that it is increasing at a rate of 7% each year. 65% BPA products are used for polycarbonate, 25% for epoxy resins, and 10% for specialty resins and flame retardants such as tetrabromobisphenol A. Products containing bisphenol A include: CDs, food can linings, fax paper, powder paints, safety helmets, bulletproof insulation panels, plastic windows, automotive parts, adhesives, protective coatings, carbonate bottles, and packaging containers (recyclable milk As well as water bottle and electric appliance covers, BPA can also be used as a reaction inhibitor and antioxidant for PVC products and their processing.

1.3 Human Exposure

Human exposure to BPA is mainly through the consumption of foods, baby bottles, dental fillings, and sealants that contain BPA material. The United Kingdom recently discovered that BPA in drinking water is mainly derived from the materials used in the water supply system, especially new pipelines. Bottled mineral water is also problematic due to mineral water in bottles made of polycarbonate (BPA synthesis) and polysulfone (synthesised with BPA, BPS). Plastic bottles of wine also have some degree of contamination.

Fetal, infant and adolescent children are most sensitive to BPA. Placental blood BPA concentration is 0.4-1.6μg/kg net tissue, that is, the fetus has not been exposed to BPA, and the amount of BPA in maternal serum is directly Affecting the health of the fetus, most of the BPA will be quickly cleared and the rest will accumulate in the blood, and the concentration will continue to increase. In addition, fish and human adipose tissue also bioaccumulate BPA.

1.4 Cumulative exposure

Many components similar to BPA also have estrogenic activity, such as bisphenol F (BPF), BPAF and bisphenol diglycidyl ether (BADGE), both of which are the basic components of plastics; BADGE is the starting component of epoxy resin and is used as The inner coating of cans is also a stabilizer and plasticizer for PVC and epoxy resin mixed materials. It is also an excellent reinforcing agent for the inner layer of polyester cans. More than 10% of European foods contain more than 1mg/kg of BADGE, and foods with high fat content are most likely to be contaminated, such as oysters, pork, anchovies, sardines, and canned fish full of oil. According to a British survey, the maximum intake will not exceed 3 μg/kg body weight/day, and the content of the most polluted anchovies is 9.3 mg/kg. If a 55kg woman takes 50g of anchovies, the intake per kg of body weight is 8.4μg.

The structure of BADGE chlorohydrin derivatives has a similar structure to some of the genetic carcinogenic substances and therefore requires special attention. Moreover, both BPA and BADGE form adducts with DNA, and in vitro experiments confirmed that BADGE does not bind to estrogen receptors, but rather effects estrogen-like effects on cell proliferation.

2 Phthalates (PAEs)

Phthalates, also known as phthalates, English name: phthalic acid
Ester, abbreviated PAEs. PAEs are used in large quantities as plastics, especially plasticizers and softeners for polyvinyl chloride plastics (PVC), which account for approximately 80% of plasticizer consumption. PAEs are also commonly used as insecticides, carriers for insecticides, additives for cosmetics, synthetic rubbers, lubricants, and additives for plastics and foil printing inks. This class of compounds contains more than 20 compounds ranging from dimethyl phthalate (DMP) to tridecyl esters. The hydrolysis and photolysis rates of PAEs are very slow and are difficult to degrade. They have a "triple effect" and are environmental endocrine disruptors. The US Environmental Protection Agency (EPA) and China have listed them as priority control pollutants.

The phthalate ester contaminants enter the human body mainly through food and water packaged in plastic containers. According to reports, DEHP content in food packaging silicone rubber products is 60 to 5830 mg/g, and DBP is 60 to 80 mg/g. The total phthalate ester concentration in high-fat foods (meat, eel, milk, cheese, margarine, or salad oil) ranges from 0.3 to 2.4 mg/kg.

In 2001, Japan investigated 16 kinds of glass, plastic, and metal-packed baby foods on the market. It was found that DBP content was 1.2 to 9.140 mg/sample in 7 samples and 1.3 to 18 mg/15 in 15 samples. According to the sample, the daily intake of DBP and DEHP for each infant is 1/2500 and 1/(90-300) of the TDI value, respectively. In addition, food handlers using a gloved handkerchief to heat the sushi can also speed up the migration of plasticizers in the glove. The survey found that DEHP (up to 40 mg/kg/day) was allowed in the sushi daily intake.

The investigation found no obvious contamination of milk during collection, transportation and packaging. The total phthalic acid ester content in raw milk ranged from 0.12 to 0.28 mg/kg. During the cheese processing process, DEHP was concentrated to a content of 1.93 mg/kg. DEHP ≤ 0.01 to 0.07 mg/kg in low-fat dairy products. It shows that phthalic acid esters are not only derived from raw materials, but also from the processing process [3].

Foods containing phthalate esters were freeze-dried and could reduce DEHP by 21.1% to 41.3%, reduce grilling by 26.1% to 52.5%, reduce cooking by 11.6% to 33.1%, reduce frying by 10.6% to 43.5%, and discover DEHP. Can be removed with moisture. In addition, when the microwave heating, the lower the boiling point of the more contaminants will evaporate, high-boiling point easily into the food.

3 Di(2-ethylhexyl) adipate (DEHA)

Di(2-ethylhexyl) adipate, English name: di-2-(ethylhexyl) adipate, abbreviated as DEHA. As a plasticizer commonly used in plastics, it has the advantages of improving the softness and cold resistance of plastics, improving light stability, and improving processing performance, and is widely used in various plastic products. Food grade plastics contain 28.3% DEHA plasticizers. Experiments have shown that DEHA can cause cancer in animals; DEHA in food comes from food packaging materials. Surveys in France, Germany, and New Zealand show that TDI values ​​have not yet been exceeded.

Similar substances include di-isononyl adipate (DINA), especially in fish-packed fish sauces, croquettes and dumplings [4]. The content of cheese is higher, up to 90.6 mg/100 g, with an average of 28.1 mg/100 g. According to the calculation of 100 g of cheese, 56% of the TDI value is achieved.

After heating the meat with PVC and P[VDC/VC] films containing dioctyl adipate (DOA) and acetyltributyl citrate (ATBC) plasticizers with octadecyl dioctyl adipate (DOA) and plasticizers, the amount of migration and heating time, and meat fat content were determined. It is related to the original concentration of plasticizer in the film. After heating for 4 min, the migration of DOA and ATBC was 14.62 mg/dm2 and 0.62 mg/dm2, respectively, but not detected in the control group (wrapped without this film).