A 2 µm Wavelength Band Low-Loss Spot Size Converter Based on Trident Structure on the SOI Platform.

A 2 µm wavelength band spot size converter (SSC) based on a trident structure is proposed, which is coupled to a lensed fiber with a mode field diameter of 5 µm. The cross-section of the first segment of the tapered waveguide structure in the trident structure is designed as a right-angled trapezoidal shape, which can further improve the performance of the SSC. The coupling loss of the SSC is less than 0.9 dB in the wavelength range of 1.95~2.05 µm simulated by FDTD. According to the experimental results, the lowest coupling loss of the SSC is 1.425 dB/facet at 2 µm, which is close to the simulation result. The device is compatible with the CMOS process and can provide a good reference for the development of 2 µm wavelength band integrated photonics.

[Study on the reorganization of standards related to food contact ceramics and porcelains].

OBJECTIVE: To solve the problem of overlap, iterance and conflict among current standards related to food contact ceramics and porcelains. METHODS: To collect all the current standards related to food contact ceramics and porcelains and reorganize them following the settled principles and method and list the standards that need to be revoked, revised, incorporated, or keep valid and excluded from the food safety standard system. RESULTS: 19 standards were collected in this study and reorganized. The main food safety indexes in these standards were the limits for lead and cadmium that released from food contact ceramics and porcelains. There were released limits for lead and cadmium in 10 standards, including 4 horizontal standards and 6 commodity standards. The provisions in these 10 standards were in conflict. And as a result of this, the 4 horizontal standards were suggested to be incorporated and revised to one food safety standard, while the 6 commodity standards were suggested to be revised and exclude the lead and cadmium provisions. Another 7 commodity standards only referenced provisions for lead and cadmium limits from horizontal standards, and these 7 standards were suggested to be excluded from food safety standard system. There were no food safety indexes in 2 standards of the 19 standards, these standards were considered not related to food safety and no need to be reorganized. CONCLUSION: There were conflicts about the released limits of lead and cadmium among the current standards related to food contact ceramics and porcelains. So, it is necessary to a set up a new food safety standard for released lead and cadmium permissible limits which can apply to all food contact ceramics and porcelains. This food safety standard should be based on food safety risk assessment and the actual situations of manufacture and usage of food contact ceramics and porcelains. The provisions in international standards and relative standards from other countries can also provide references to this standard.

[Study on melamine migration rules in products of tripolycyanamide for food packaging].

OBJECTIVE: To study the migration rules of melamine in products of tripolycyanamide for food packaging. METHODS: With different stimulant solutions, temperatures exposure and long term use, the migration quantities of melamine in products of tripolycyanamide for food packaging into 3% acetic acid and 15% ethanol were measured by HPLC method. RESULTS: The amounts of melamine migrated to 3% acetic acid was higher than those to 15% ethanol. Higher temperatures more amounts of melamine of products of tripolycyanamide were migrated. With the higher temperature exposure was done, the amount of melamine migration reached maximum in lower number of repeated exposures. After 10 times of migration tests, melamine still can be migrated but the amount was not high. The single maximum migration amount was 0. 0851 mg/dm2, and the value was approximately 1/59 of the SML regulated by EU regulations. CONCLUSION: 3% acetic acid is the most serious solvent. The higher the temperature, the greater the migration, and melamine still migrate after repeated use.

[Overview and analysis of food chemical contaminant monitoring in 2000-2009 in China].

OBJECTIVE: To know about food safety situation and provide scientific data for the development of food safety policies and laws. METHOD: Monitoring task was carried out in some areas of China by some measures and steps such as formulating plan, compiling SOP, holding technical training, having quality controls, data collection, checking and statistics of food chemical contaminant monitoring. RESULTS: 14 categories of foods and 129 chemicals were cumulatively surveyed in 16 provincial areas for ten years. A database with more than 1.05 million monitoring data was established. Monitoring results showed that food safety situation in China was generally stable and gradually good, but also problems of some food safety were found. Monitoring data had been used for alerts, supervision, risk assessment and standard setting of food safety. CONCLUSION: The monitoring for 10 years knew about the contamination levels and dynamic trend of contaminants in food, provided scientific data for the development of food safety policies and laws, and laid the foundation for national food contamination monitoring.

[Foodborne disease outbreaks in 2006 report of the National Foodborne Disease Surveillance Network, China].

OBJECTIVE: To study the epidemiological characteristics of foodborne disease outbreaks in China in 2006. METHODS: The foodborne diseases data collected by the National Foodborne Disease Surveillance Network in 2006 were analyzed. RESULTS: There were 594 outbreaks of foodborne disease reported from 18 provinces in 2006, which caused illness in 13849 persons and death in 67. Among outbreaks for which the etiology was determined, microbial pathogens caused the largest percentage of outbreaks (48.3%) and the largest percentage of cases (63.3%), chemical agents, 24.8% of outbreaks and 15.5% of cases, and animal and plant agents, 23.5% of outbreaks and 17.7% of cases. CONCLUSION: As discovered by the National Foodborne Disease Surveillance Network, microbial foodborne disease remains a major public health problem in China, and the awareness to report foodborne disease incidents need to be intensified in the future.

[Study on maximum fortification level of calcium in food].

OBJECTIVE: To explore appropriate method for determining maximum levels of micronutrient fortification, and use calcium as an example, maximum levels were suggested for the revise of the standards of food fortification in China. METHODS: Based on the principle of risk assessment, the data of China National Nutrition and Health Survey in 2002 were used to explore the model for calculating the maximum levels of micronutrient fortification. The data were stratified by economical development level, age, as well as gender, and the maximum levels of calcium fortification were determined accordingly, among which the lowest value was suggested as maximum level of calcium fortification. RESULTS: MSFLs for all the age groups of big cities, M&S cities and rural I were lower than those of the whole population. MSFL for 18- age group of rural I was the lowest one in the corresponding age groups. And the lowest MSFLs for 2 - 7 and 11 - 18 age group lies in big cities. The lowest MSFL for all of age groups was set as 262 mg/1000 kJ. CONCLUSION: This model could be applied to derive MSFL for nutrient fortificants with UL.

Assessment on dietary melamine exposure from tainted infant formula.

OBJECTIVE: To estimate the dietary melamine exposure in Chinese infants and young children from the consumption of melamine adulterated Sanlu infant formula. METHODS: Four age groups of infants and young children (3, 6, 12, and 24 months) were chosen as the assessed subjects and the maximum amount of infant formula consumption was estimated based on the recommended usage level in the package insert of Sanlu infant formula and other brands. Melamine was analyzed in 111 Sanlu infant formula samples collected from the markets in Beijing and Gansu province using the LC-MS-MS with a limit of quantification of 0.05 mg/kg. Four levels of melamine concentration were chosen to estimate the dietary intakes, including the mean, median, 90th percentile, and maximum. RESULTS: The infants of 3 months had the highest intake of melamine, and with the increase of the age (month), the intake decreased. Based on the median melamine concentration (1,000 mg/kg) as an example, the melamine intakes for the infants of 3, 6, 12, and 24 months were 23.4, 21.4, 15.0, and 8.6 mg/kg bw/d, respectively. CONCLUSION: Dietary melamine intakes from tainted Sanlu infant formula significantly exceeded the TDI level (0.2 mg/kg bw/d) recommended by the WHO Expert Meeting in 2008. However, the present assessment has some limitations including the poor representative samples, the varied melamine concentrations in the adulterated Sanlu infant formula, and other brand infant formula possibly consumed by these infants.

Study on migration of melamine from food packaging materials on markets.

OBJECTIVES: To study the migration of melamine into foods from plastic food packaging materials and dairy product containers commonly used in China. METHODS: 37 samples were collected from the market. The EU migration testing conditions were adopted with distilled water, 3% acetic acid, n-hexane and 15% ethanol being chosen as the simulating solutions. The HPLC method was used to detect melamine. RESULTS: No melamine was detected in 15 dairy product containers. Among the 22 plastic samples, 16 of polypropylene, and polycarbonate types had no detectable amount melamine while a low level of melamine was found in 3 of the 6 melamine resin containers. CONCLUSION: Migration of melamine from food packaging materials in China market is in line with the requirements of EU.

[Study on the determination method of the astragaloside IV in health food].

OBJECTIVE: To built an analytical methods to test Astragaloside NV in health food. METHODS: The reaction conditions of ultrasonic extraction, liquid-liquid extraction, macroporousresin column chromatography, solid-phase extraction, derivatization and HPLC method were analyzed. RESULTS: The sample preparations were set up as followed: The samples were extracted with methanol. The extraction solutions were liquid-liquid extracted by ether, water-saturation n-butyl alcohol and 1% KOH. The extraction solutions were further purified by DM-301 macroporousresin column chromatography and Oasis HLB 3cc extraction catridge in turn. The purified solutions were derived with chloroform and benzoyl chloride. The linear ranges were 3.84 - 153.60 microg/ml. The detection limits were 2.13 microg/ml. The recoveries were 74.85% - 91.83%. CONCLUSION: The method was applied to detect the concentration of Astragaloside IV in health food. It was enough to wipe out impurity of samples. Detection limit and recycle ratio were satisfied.

[Study on development of the principles for determination and evaluation of antimicrobial effectiveness of food preservatives].

OBJECTIVE: To establish the principles for determination and evaluation of the preservative properties demonstrates the effectiveness of a substance when used as a food preservative. METHODS: Sorbic acids were chosen as the model food preservative and the Gram positive bacterium Staphylococcus aureus, Gram negative bacteria Escherichia coli and Salmonella enteritidis, yeast Candida albicans and the filamentous fungus Aspergillus niger, A. flavas, Geotrichum candidum, Penicillium islandicum and Peniciuium cyclopium were employed as the experimental microorganisms. The test involves adding fresh and active cultures standardized to a concentration between 10(2) and 10(5) cfu/ml directly to sorbic acid solution at different concentrations ranged from 0.25 to 2 g/L to simulate contamination. The mixture was held for two days and microorganism survivals were monitored at regular intervals of 3, 6, 24 and 48 h, respectively. RESULTS: Sorbic acids were active against an extensive range of bacteria, yeasts and molds. The inhibition got stronger and stronger with either the extension of time against microorganisms or the increasing in concentration of sorbic acid. The antibacterial activity of sorbic acid were a little bit stronger than its antimycotic activity, with the lower minimum inhibitory concentration and the shorter inhibitory time in bacteria than those in fungi. In general, Gram negative bacteria were more sensitive to sorbic acid than Gram positive one. CONCLUSION: The experimental design could be science-based, sound and available in evaluation of the antimicrobial effectiveness of food preservatives.

[National continuous monitoring on the content of lead in preserved eggs from 2000 to 2006].

OBJECTIVE: To investigate the pollution level and development trend of lead in the preserved egg in our country. METHODS: By the national food contamination monitoring system and under the strict analysis quality control, the content of lead in the preserved eggs was analyzed according to the national standard method (GB/T 5009.12-2003) in fourteen provinces from 2000 to 2006. RESULTS: All 1358 data on contents of lead in the preserved eggs were obtained during seven years, the total average was 1.782 mg/kg, the maximum was 334.0 mg/kg, P90 was 3.50 mg/kg, P95 was 7.397 mg/kg and P97.5 was 12.01 mg/kg, all exceeded 2 mg/kg of the national limit standard, and the rate of violated samples exceeded 10.0%. Analyzing from time, contents of lead in the preserved eggs were depressive from 2.994 mg/kg to 1.138 mg/kg year after year. CONCLUSION: The lead contamination in preserved eggs was serious in whole country. It shows that the continuous work of monitoring and forewarning should be carried out to make the contamination of lead in preserved eggs to reduce year by year.

[Determination of bisphenol A and alkyl phenols in canned food with high performance liquid chromatography--fluorescence].

OBJECTIVE: To establish a comprehensive analytical high performance liquid chromatography fluorescence detection (HPLC-FL) in detecting bisphenol A (BPA), nonylphenol (NP) and octylphenol (OP) in canned food sold in Beijing markets. METHODS: BPA, NP and OP was extracted with methanol and dichloroacetamide and concentrated. The samples were purified on an solid extraction cartridges. The HPLC system consisted of Waters XTerra MS C18 column, a mixture of methanol and water as mobile phase and fluorescence detector with the excitation and emission wavelength at 225 nm and 310 nm respectively. RESULTS: The method established had a linear relationship, showing the detection limit of BPA, OP and NP being 0.5, 0.1 and 0.1 microg/kg in canned vegetable and instant noodle and 1, 0.5 and 0.5 microg/kg in canned fish and meat can, respectively. The recoveries of BPA, NP and OP were 74.9%-95.1% , 76.3%-103.6% and 72.1%-109.2%. The precision was 4.98%-11.2% , 2.35%-8.88% and 5.61%-12.3%, respectively. CONCLUSION: The method is simple with high sensitivity and selectivity, suitable for the determination of NP, OP and BPA in canned food.

[Survey on the cadmium levels in fish, crustaceans and bivalve mollusks in China of 2002].

A survey on the cadmium content of fresh water, marine fish bivalve mollusks and crustaceans in China was carried out by the National Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention in 2002. The fish from fresh water (n = 193), marine (n = 367), crustaceans (n = 318) and bivalve mollusks (n = 512) were collected from 14 provinces and cities and analyzed by AAS. It was found that the samples with mean concentration between 0.06-0.53 mg/kg. However, some of samples were up to 8 mg/kg, indicating that the cadmium content of some fishes exceeded the maximum level of national standards.

[Study on the determination of chloramphenicol residues in muscles and viscera of the livestock and poultry and in the shrimp].

OBJECTIVE: A rapid, simple and sensitive high performance liquid chromatographic method for the determination of chloramphenicol residues in muscles and viscera of the livestock and poultry and in the shrimp has been established. METHODS: The chloramphenicol in animal tissues is extracted three times by ethyl acetate in ultrasonic. The extract is dehydrated with Na2SO4 and concentrated. The residues are cleaned up by 0.5 mol/L HClO4 and n-hexane. The purified solution is detected at UV 278 nm by HPLC. RESULTS: The detection limit of this method is 1.6 micrograms/kg in muscles and 3.2 micrograms/kg in viscera, the recovery is from 82.1% to 96.6%, RSD is 5.3%-6.4%. CONCLUSION: This method can be widely applied to animal-foods, and its recovery is high, and its detection limit is low, and it is easily popularized in countryside.

[Study on national active monitoring for food borne pathogens and antimicrobial resistance in China 2001].

OBJECTIVE: To survey food borne pathogens and antimicrobial resistance in China. METHODS: A total of 4034 samples of foods (raw meats, raw milk, cooked meats, ice cream, yoghurt, aquatic product and vegetable) were examined for the presence of Escherichia coli O157:H7 Salmonella spp and Listeria monocytogens by national active foodborne pathogens surveillance system. The samples were obtained from 11 provinces in 2001. RESULTS: Approximate 5.50% of the all samples yielded 3 pathogenes, whereas Escherichia coli O157:H7 (0.82%), Salmonella servoars (3.32%) and Listeria monocytogens (1.29%). The most heavy contamination by three food borne pathogens are in raw meat (12.96%). Top seven serotype of the 137 Salmonella isolates are S. derby, S. agona, S. enteritidis, S. reading, S. anatum. S. muenster, S. typhimurium. CONCLUSION: Serotypes and antibiotic resistance patterns of Salmonella isolates are different in 11 provinces. E. coli O157:H7 strains that are isolated from raw meat and cooked meat have VT2, eae, Hly genes. Salmonella and E. coli strains of multidrug resistance were isolated and identified.

[Study on food contaminants monitoring in China during 2000-2001].

The contamination levels of 10 main kinds of foodstuffs in 11 provinces and cities were monitored by the national food contamination monitoring system from 2000-2001. About 45 thousand data were obtained in strict quality control. The data indicated that the contamination level of lead was increased in 10 years in meat, eggs, milk-based products especially in preserved eggs, but the contamination levels of arsenic, cadmium and hydrargyrum were not serious by adopting the national standards. Organochlorine pesticides residues (666, DDT) maintained downtrend and organophosphorus pesticides residues met the national associated criteria except methyl parathion in cereals.