Surveying On Use Of MF Tableware In Catering And Risk Assessment On Two Initial Monomers Of MF By Simple Exposure Assessment Models.

Product of melamine-formaldehyde for food contact materials are more and more universally used by families,schools,restaurants,fast-food restaurants,snack bars and etc.Because it is not easy to disrupt,many parents serve it as child tableware.It has become a hot topic to the government,the consumers and the news Medias whether melamine-formaldehyde resin releases melamine,formaldehyde or other virulent,the deleterious substances.Three aspects were studied by scientifically and systematical methods in this research.They were surveyed on use of MF tableware in caterings,study on migration rule,migration experiment,migration mathematical model of melamine and formaldehyde,simple model risk assessment on melamine and formaldehyde in MF tableware.Following are main results and conclusions of the study.â… .What utilization ratio of MF tableware was relatively high was the fast-food restaurants and the snack bars.The area of catering and the usage of MF tableware are not obvious relevance.Whether there is the hygienic permit in using MF tableware by catering didn't have statistics difference.â…¡.The ratios of using MF to process food in microwave were nearly close in the economical developed area and the economical non-developed area.But the economical general area would be higher than the above nearly ten percentage points.The ratio of using melamine tableware in city and countryside was higher than in the city and in the countryside.â…¢.In four high risk processing way,the high temperature processing operation located at first,and then in turn is fatty,the acidic,highly concentrated alcohol.â…£.6 essential factors were paid great attention in when purchaser bought tableware. Hygienic permit and brand of tableware rowed at final two.4 essential factors were paid great attention in when catering used tableware.Application temperature of tableware was paid the least attention to.â…¤.HPLC method was established to analysis melamine in the packing materials.â…¥.Migration rules of melamine and formaldehyde were studied in the research.â…¦.The higher temperature was used,the more quantity of melamine and formaldehyde was migrated.3%acetic acid was stronger stimulant towards the two initial chemical compounds than 15%ethanol.Melamine was still migrated after 10 repeated exposures,but the amount of it is little.Maximum value of formaldehyde migration was achieved after several repeated exposures,and 0 mg/dm² of the migration quantity may be appeared in the last.â…§.The ratios of volume and the internal surface of samples collected in market were measured and calculated accumulate carries on the determination.The scope was 1.14～3.27 mL/cm² which could not meet 2mL/cm².â…¨.Migration of melamine from all sample didn't exceeded the corresponding limit for melamine in EU.In 53.66%samples the formaldehyde migration quantity exceeded specific migration limits of European Union(SML).Study on the ratio of formaldehyde/MF migrated.The range was 0.8～10033.0 and the greatest ratio was theory maximum value 2090.2 times.â…©.Based on the Fick law's diffused behavior and only considered one-dimensional diffusion,monolayer diffusion mathematical model was established for chemical materials migrated from MF products.Fit the linear through the least squares method to calculate diffusion coefficients of formaldehydes.The values were D_{3%乙酸,60℃} =2.507×10^-7,D_{3%乙酸,75℃}=1.391×10^-6,D_{3%乙酸,90℃}=1.472×10^-6,D_{15%乙酸,60℃} =1.025×10^-8,D_{15%乙醇,75℃}=5.560×10^-8,D_{15%乙醇,90℃}=1.453×10^-6.The diffusion coefficients of melamine were calculated as them of formaldehydes.The values were D_{3%乙酸,60℃}=8.129×10^-9,D_{3%乙酸,75℃}=1.119×10^-7,D_{3%乙酸,90℃}=1.157×10^-7,D_{15%乙醇,60℃} =7.819×10^-9,D_{15%乙醇,75℃}=2.504×10^-8,D_{15%乙醇,90℃}=1.637×10^-7.Moreover, distribution coefficients of formaldehyde and melamine in two phases were calculated.The distribution coefficients of formaldehyde were K_{3%乙酸,60℃}=25.39, K_{3%乙酸,75℃}=17.23,K_{3%乙酸,90℃}=16.33,K_{15%乙醇,60℃}=160.46,K_{15%乙醇,75℃}=65.76, K_{15%乙醇,90℃}=35.65 and them of melamine were K_{3%乙酸,60℃}=527.53,K_{3%乙酸,75℃} =184.29,K_{3%乙酸,90℃}=137.91,K_{15%乙醇,60℃}=17791.12,K_{15%乙醇,75℃}=756.36,K_{15%乙醇,90℃} =216.07.â…ª.Even if selected "badly" situation,the dietary exposure intakes of melamine which was one of the initial monomers MF products were still lower than its TDI value.The results of risk assessment showed that it was safe to all groups by using melamine products to intake melamine.But regarding the other initial monomer-formaldehyde,the situation is unoptimistic.Using the simple distribution model to assess it,the ADI value was located at 74.8%～88.97%of the distribution.Along with the age increasing,the exposed value presented declining trend.To the high-risk group-child groups,the exposed values were very high.The exposed values of formaldehyde to urban people were little lower than to countryside people what showed the security of urban people was relative higher than it of countryside people.The formaldehyde exposed value to man is higher than woman as a whole.