Molecular epidemiology of Listeria monocytogenes isolated from ready-to-eat food in 2017 in China / 中华预防医学杂志

Objective@#To analyze the molecular characteristics of Listeria monocytogenes strains from ready-to eat food in China.@*Methods@#A total of 239 Listeria monocytogenes strains isolated from ready-to-eat food in 2017, all strains underwent whole-genome sequencing (WGS) , and comparisons uncovered population structure derived from lineages, clonal complex, serogroups, antimicrobial susceptibility and virulence, which were inferred in silico from the WGS data. Core genome multilocus sequence typing was used to subtype isolates.@*Results@#All strains were categorized into three different lineages, lineage Ⅱ was the predominant types in food, and IIa was the main serogroups. CC8, CC101 and CC87 were the first three prevalent CCs among 23 detected CCs, accounting for 49.4%. Only 4.6% (11 isolates) of tested strains harbored antibiotic resistance genes, which were mostly trimethoprim genes (7 isolates, 2.9%). All strains were positive for LIPI-1, and only a part of strains harbored LIPI-3 and LIPI-4, accounting for 13.8% (33 isolates) and 14.2% (34 isolates), respectively. ST619 carried both LIPI-3 and LIPI-4. 51.5% (123 isolates) of strains carried SSI-1, and all CC121 strains harbored SSI-2. Different lineages, serogroups and CCs can be separated obviously through cgMLST analysis, and 24 sublineages were highly concordant with CCs.@*Conclusion@#Ⅱa was the main serogroups in ready-to-eat food isolates in China; CC8, CC101 and CC87 were the prevalent CCs, and CC87 isolates was hypervirulent isolates, cgMLST method can be adopted for prospective foodborne disease surveillance and outbreaks detection.

Estimated assessment of cumulative dietary exposure to organophosphorus residues from tea infusion in China

BACKGROUND@#China has the world's largest tea plantation area in the world. To sustain high yields of the tea, multiple pesticides are used on tea crops to control pests. Organophosphorus (OP) pesticides are among the most widely used types of agricultural pesticides in China. As tea is a significant potential source of exposure to pesticide residues, the public concern has increased in relation to pesticide residues found in tea in China. The aim of the study was to estimate cumulative dietary exposure to OP residues from tea infusion for Chinese tea consumers to determine whether exposure to OP residues from tea infusion is a cause of health concern for tea consumers in China.@*METHODS@#OP residue data were obtained from the China National Monitoring Program on Food Safety (2013-2014), encompassing 1687 tea samples from 12 provinces. Tea consumption data were obtained from the China National Nutrient and Health Survey (2002), comprising 506 tea consumers aged 15-82 years. The transfer rates of residues from tea leaves into tea infusions were obtained from the literature. The relative potency factor (RPF) approach was used to estimate acute cumulative exposure to 20 OP residues from tea infusion using methamidophos as the index compound. Dietary exposure was calculated in a probabilistic way.@*RESULTS@#For tea consumers, the mean and the 99.9th percentile (P99.9) of cumulative dietary exposure to OP residues from tea infusion equalled 0.08 and 1.08 μg/kg bw/d. When compared with the acute reference dose (ARfD), 10 μg/kg bw/d for methamidophos, this accounts for 0.8 and 10.8% of the ARfD.@*CONCLUSIONS@#Even when considering OP residues from vegetables, fruits and other foods, there are no health concerns based on acute dietary exposure to OP residues from tea infusion. However, it is necessary to strengthen the management of the OP pesticides used on tea in China to reduce the risk of chronic dietary exposure to OPs from tea infusion.

Liquid milk exposure and risk assessment of thiocyanate in Chinese populations / 中华预防医学杂志

Objective@#To analyze liquid milk exposure of thiocyanate among Chinese population and preliminarily assess its health risk.@*Methods@#A total of 2 059 raw milk samples were collected during 2013 and 2014 from 12 Chinese provinces, New Zealand and Netherlands. Farms were chosed according to the main sources of dairy companies, the distribution of farms and the yield of milk. Content of thiocyanate were detected by ion chromatography. Liquid milk consumption data were taken from Chinese beverage and alcoholic beverage consumption survey in 18 cities or counties in 9 provinces, including 16 775 subjects older than 3. A simple distribution model was used to estimate the exposure of thiocyanate from liquid milk. The tolerable daily intake (TDI) of thiocyanate was made 0.08 mg·kg-1·d-1. Then the exposures of different age groups were compared with TDI.@*Results@#Finally, 1 331 samples out of 2 059 were detected to contain thiocyanate. The detection rate was 65%. The average concentration of thiocyanate was 2.11 mg/kg, with a range of 0.10-16.20 mg/kg. The general population's consumption of thiocyanate by drinking liquid milk was 0.001 mg · kg-1 · d-1, which was lower than TDI. The P95 of general population and consumers were 0.009 mg · kg-1 · d-1 and 0.020 mg·kg -1·d-1 respectively, which were also lower than TDI. Mean exposures of population aged 3-6, 7-12, 13-17, 18-59 as well as elderly aged 60 and above were 0.007, 0.003, 0.002, 0.001 and 0.001 mg · kg-1·d-1 respectively, which were all lower than TDI.@*Conclusion@#The results suggested that the health risk of thiocyanate exposure by drinking liquid milk among Chinese population was at a low level. However, milk products for children deserve more concern.

Dietary intake and risk assessment of diethylhexyl phthalate in Chinese populations / 中华预防医学杂志

<p><b>OBJECTIVE</b>To assess dietary exposure of diethylhexyl phthalate(DEHP) among Chinese population, including general population, children aged 2-6 years, adolescent aged 7-12, young people aged 13-17, adults aged 18-59 years old as well as older people aged 60 and above and its health risk.</p><p><b>METHODS</b>A total of 6 650 food samples were collected during 2011 to 2013 from 140 local markets of 14 provinces in China, which covered major foods in China. Samples were detected by GC-MS and categorized into 22 food groups. Food consumption data were taken from China National Nutrition and Health Survey performed in 2002 including 68 959 subjects. Mean concentrations of DEHP in food were combined with individual food consumption data to estimate dietary exposure, and food contributors to dietary DEHP intake were also calculated. Then, the exposure was compared with the tolerable daily intake (TDI, 50 µg·kg(-1)-d(-1)) of DEHP.</p><p><b>RESULTS</b>DEHP level in foods (n = 6 650) was in the range of not detected to 43.80 mg/kg. Mean dietary intakes of DEHP in general population was 2.07 (95% CI: 0.06-4.09) µg·kg(-1)·d(-1), accounting for 4.14 percent of TDI (50 µg·kg(-1)·d(-1)). Mean dietary intake for population aged 2-6, 7-12, 13-17, 18-59 as well as elderly aged 60 and above were 3.92 (95% CI: 0.83-7.01), 3.02 (95% CI: 0.69-5.36), 2.17 (95% CI: 0.54-3.81), 1.83 (95% CI: 0.46-3.21) and 1.66 (95% CI: 0.38-2.94) µg·kg(-1)·d(-1) respectively. The 97.5 percentile intakes in the general populations was 4.73 µg·kg(-1)·d(-1), accounting for 9.46% of TDI. Main food sources of DEHP were rice (28.4% (0.59/2.07)), melon solanaceous vegetables (14.7% (0.30/2.07)) and flour (13.2% (0.27/2.07)) for the general population.</p><p><b>CONCLUSION</b>The results suggested that dietary exposure to DEHP among Chinese population was lower than tolerable daily intake of DEHP and there were no health concerns based on generally accepted exposure limits. Rice, melon solanaceous vegetables and flour were main food contributors of DEHP dietary intake for Chinese populations.</p>

Study on detection of Salmonella in poultry samples by real-time PCR with Taqman probes / 中华预防医学杂志

<p><b>OBJECTIVE</b>To develop a RT-PCR method for a rapid and sensitive detection of Salmonella in poultry samples.</p><p><b>METHODS</b>The RT-PCR method was established and its specificity was testified on the basis of invA gene. Serial 10-fold diluted pure suspension culture of CMCC 50041 was detected by RT-PCR, the standard curve was constructed and the amplification efficiency was calculated. Artificially contaminated experiment was done, six artificially-inoculated samples containing final concentration of Salmonella CMCC 50041 (1, 10, 10(2), 10(3), 10(4), 10(5) and 10(6) CFU per 25 g poultry samples) were prepared respectively. All the samples were incubated for 0, 4, 8, 12 and 18 h and the DNA was extracted for RT-PCR detection, meanwhile by PCR detection and the traditional method. The sensitiveness and specificity were compared among the three methods. At the same time, 16 samples of retail whole poultry were collected from markets and detected by the above three methods as well, and thereby to further compare the positive detection among the three methods.</p><p><b>RESULTS</b>The established RT-PCR method was specific for the detection of Salmonella. The sensitivity was 5.2×10(3) CFU/ml for pure Salmonella culture without enrichment. Correlation coefficients of standard curves constructed using the Ct versus log value of concentration of Salmonella showed good linearity over a 8-log dynamic range (5.2×10(3)-5.2×10(10) CFU/ml), with the R(2) at 0.999. RT-PCR detection limit for artificially contaminated samples after enriching for 12 h was 1 CFU/25 g sample, which was the same with the limit of PCR and 10 times more sensitive than the limit of traditional method. Standard curve of sample after enrichment for 12 h was established. Seven of 16 samples were detected positive by RT-PCR, which were also tested positive by PCR, while only five samples were positive by traditional method. The positive ones were quantitatively analyzed using standard curve of sample and determined the initial Salmonella numbers of CFU/25 g.</p><p><b>CONCLUSION</b>The established RT-PCR technology was simple, rapid, sensitive and specific, which was suitable to quickly detect Salmonella in poultry samples.</p>

Pereutaneous puncture and craniotomy for hyperacute traumatic intracranial hematoma / 中华创伤杂志

Objective To discuss the experiences in successful treatment of hyperacute traumatic intracranial hematoma with percutaneous puncture and craniotomy.Methods Pereutaneous puncture and craniotomy was performed in 12 patients with hyperacute traumatic intracranial hematomas including seven with subdural hematoma,three with epidural hematoma and two with episubdural hematoma.Before operation,there found enlargement of bilateral pupil in six patients,enlargement of unilateral pupil in six and changed breathing rhythmicity in eight.Glasgow Coma Scale(GCS)was 3 points in four patients,4 points in six and 7 points in two.Results After pereutaneous puncture,enlarged pupil was retracted at different degrees in nine patients and spontaneous breathing conditions improved in seven.After crani otomy,two patients died within 24 hours,four died after 24 hours but six patients survived.The follow-up for 0.5-2 years showed four patients with sound Glasgow Outcome Score,two at vegetative state and six deaths.Conclusion Percutaneous puncture combined with craniotomy is an effective way for hyperacute intracranial hematoma.

Study on the determination method of chromium picolinate in health food / 中国食品卫生杂志

For developing the determination method of chromium picolinate in health food by HPLC,extraction method and HPLC operation conditions such as columns,mobile phase had been optimized.Long term stability test of chromium picolinate had been done.Recovery of the standard spiked >93%,the RSD was 3.1,the lowest detection limit was 10.0 mg/kg,the result fits the demand of the analysis of health food.This method can be used in analysis of the content of chromium picolinate in types of tablet and capsule health food.2 years store experiment in room temperature showed that chromium picolinate was stable.

Study on the determination method of chromium picolinate in health food / 中国食品卫生杂志

For developing the determination method of chromium picolinate in health food by HPLC,extraction method and HPLC operation conditions such as columns,mobile phase had been optimized.Long term stability test of chromium picolinate had been done.Recovery of the standard spiked >93%,the RSD was 3.1,the lowest detection limit was 10.0 mg/kg,the result fits the demand of the analysis of health food.This method can be used in analysis of the content of chromium picolinate in types of tablet and capsule health food.2 years store experiment in room temperature showed that chromium picolinate was stable.

Study on the determination method of chromium picolinate in health food / 中国食品卫生杂志

For developing the determination method of chromium picolinate in health food by HPLC,extraction method and HPLC operation conditions such as columns,mobile phase had been optimized.Long term stability test of chromium picolinate had been done.Recovery of the standard spiked >93%,the RSD was 3.1,the lowest detection limit was 10.0 mg/kg,the result fits the demand of the analysis of health food.This method can be used in analysis of the content of chromium picolinate in types of tablet and capsule health food.2 years store experiment in room temperature showed that chromium picolinate was stable.