Phthalic acid esters are used as plastic softeners and also can be found in food packaging materials. European legislation defines specific migration limits of plastic additives for plastic materials that come into contact with food. This study monitors the phthalic acid ester concentrations in yogurts after manufacturing and then after a 3‑week storage. The studied yoghurts were natural yogurt with 1 % of chia flour, natural yogurt with 5 % of chia flour, natural yogurt with 1 % of bamboo fibre, natural yogurt with 5 % of bamboo fibre and natural yogurt. The analysed phthalic acid esters were dibutyl phthalate (DBP) and di‑(2‑ethylhexyl) phthalate (DEHP). The average phthalate concentrations in plastic cups were detected for DBP of 59.5 µg/g and for DEHP of 9.0 µg/g of the plastic material. Higher DBP concentrations than DEHP concentrations were also found in all studied yogurts. The average DBP concentrations in yogurts were detected from 1.8 µg/g up to 5.0 µg/g of the original matter and the average DEHP concentrations were determined from 0.5 µg/g up to 1.0 µg/g of the original matter. No statistically significant difference was found when comparing phthalic acid ester concentrations in yogurts immediately after production and after three weeks of storage. However, in our study in all cases of yogurts, the DBP concentrations were higher than the specific migration limit set by the legislation (0.3 mg/kg) and the DEHP concentrations were in all cases of yogurts lower than the specific migration limit set by the legislation (1.5 mg/kg).

Abstract. The aim of this work was to determine the concentrations of phthalic acid esters (PAEs) in plastic materials used in automobiles and monitor the changes in concentrations over time. The phthalates can be released into the car interior during the operation of the vehicle and thereby inhaled by the driver, or the PAEs can migrate from plastics to the surrounding contact materials. Esters of phthalic acid are used as plasticizer of plastics. They are not chemically bonded in polymers, so they can migrate into materials, which are in contact with them, leach or evaporate into the environment. Phthalic acid esters have teratogenic and carcinogenic effects and negative effects on the male reproductive system. In this study the most commonly used phthalates were determined: dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP). Nine samples of plastic materials that are used in the car interior were analysed. The samples were new plastics, which were made for car mounting. Each sample of the plastic material was subdivided into individual components, from which the sample consists, and each part of every sample was analysed separately. The first sample analysis was performed immediately after the obtaining of the plastic samples (after the plastics production) and subsequently after 3 months. The samples of plastic automobile components were transported in the car in the period between the two analyses. The car was used in normal operation. It simulated the actual plastic environment, where these plastics are normally placed. All analyses were performed in triplicate. In total, they were 18 samples of plastics analysed and 108 analyses were performed. Phthalic acid esters were determined by high pressure liquid chromatography.

The presence of dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) was monitored in 16 automotive plastic samples (steering wheel, dashboard, seats, headrests, and air conditioning control). The plastic samples were obtained from a crashed vehicle that had been in operation for only one month. Phthalates were determined by HPLC. The first analysis was performed immediately after the sample preparation, the second one after 3 months of storage, the third one after 6 months of storage, the fourth one after 9 months of storage, and the fifth one after 15 months of storage. The average DBP concentrations ranged from 1.3 to 197.1 μg g–1 of plastic at the beginning, 1.7to 161.5 μg g–1 of plastic in the 3rd month, 0.5 to 78.9 μg g–1 of plastic in the 6th month, 2.3 to 123.3 μg g–1 of plastic in the 9th month, and 14.0 to 98.6 μg g–1 of plastic in the 15th month. The average DEHP concentrations ranged from 1,7 to 185,7 μg g–1 of plastic at the beginning, 3,9 to 45,4 μg g–1 of plastic in the 3rd month, 1,4 to 252,4 μg g–1 of plastic on the 6th month, 5,1 to 41,7 μg g–1 in the 9th month, and 2,3 to 87,5 μg g–1 in the 15th month. In particular, higher concentrations were found in soft plastics. An interesting finding is that the content of both phthalates (DBP and DEHP) was also present in leather materials. According to the comparison of phthalates concentrations during storage, it can be stated that phthalates concentration decreases with time and, after approximately 15 months of storage, concentrations decreased: for DBP by 20 to 90% (in 44% samples) and for DEHP by 30 to 90% (in 70% samples). For the other samples, the increase of both phthalates was probably due to depolymerisation of the plastics by UV exposure, temperature and storage time. Phthalates are human carcinogens and they can cause the death or tissue malformation. They are dangerous for liver function. The legislation of the Czech Republic and European Union has not yet dealt with these problems.

In our research the influence of thermal heating on the release of plasticizers from plastics into the meat product and water was researched. The two most widely used plasticizers, dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP), were detected. Both of the plasticizers have a negative effect on the health. And both are regulated by regulation of the European Union. In this study were researched phthalates in products prepared by sous-vide technology and it was studied effect of reheating on migration of phthalates. The average concentrations of both phthalate esters, DBP and DEHP, in heated water decreased. The average concentration of DBP in water before heating was detected 0.82 mg/100 ml and after heating 0.52 mg/100 ml, the average concentration of DEHP in water before heating was established 0.33 mg/100 ml and after heating 0.19 mg/100 ml. In plastic wraps, average DBP concentration with reheating increased and average DEHP concentration with reheating dropped. The average DBP concentration in plastic packaging, heating at 60 °C/12 h was determined of 9.87 mg/dm2 after reheating 60 °C/1 h was detected of 15.40 mg/dm2. The average concentration of DEHP in plastic packaging, heating at 60 °C/12 h was determined of 58.71 mg/dm2 and after reheating 60 °C/1 h was detected of 28.28 mg/dm2. The average DBP concentration in meat products due to reheating decreased, the average DEHP concentration in meat products increased. The average DBP concentration in meat products heating at 60 °C/12 h was detected of 8.39 mg/g dry matter and after reheating of 6.43 mg/g dry matter, the average DEHP concentration heating at 60 °C/12 h was determined of 25.37 mg/g dry matter and after reheating of 65.51 mg/g dry matter..

Phthalic acid esters are plasticizers, they can migrate freely from plastic to their surroundings. They have negative health effects. European legislation sets specific migration limits for phthalic acid esters. In our study, we deal with two esters of phthalic acid, dibutylphtalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP). It was studied the effect of storage of four types of yoghurt on the concentration of phthalic acid esters. Yoghurts contained 1% chia flour, 5% chia flour, 1% bamboo fiber and 5% bamboo fiber. Yoghurts were stored in plastic cups, which contained both examined phthalic acid esters. Esters of phthalic acid were determined after 1 week of storage then after 2 weeks of storage and in the original raw material. Furthermore, the pH of the yoghurt was determined. The pH values were correlated with phthalate concentrations: the correlation coefficient for DBP with a pH of -0.0265 and for DEHP with a pH of 0.3075. Mean concentrations of DEHP decreased over time, while DBP decreased for yoghurt with 1% chia flour, while in other cases they increased. The mean DBP concentrations in yoghurt were higher than the average concentrations of DEHP. Comparing the mean sample values with t-test for dependent samples for yoghurt of the same type, when comparing the DBP or DEHP concentration in week 1 with the DBP or DEHP concentration at week 2, the mean values were consistent. It can be noted that there was no increase in DEHP concentrations from cups to yoghurts, which was probably due to a lower concentration in cups than the DBP concentration. DBP concentrations increased in 3 of the 4 types of yoghurt. The determined pH in yoghurts did not differ significantly. Apparently a greater effect on the migration of phthalic acid esters will have in our case a different yoghurt consistency than pH. It would be appropriate to examine the effect of food density on the migration of phthalic acid esters. Likewise, it would be appropriate to examine the effect of pH but in the same food with different pH on the migration of phthalic acid esters.