Enshi sulfur dioxide residues in food risk assessment

. From 2012 to 2019, the risk monitoring of food chemical contaminants and harmful factors in Enshi Prefecture found that the sulfur dioxide residues in food exceeded the standard seriously, and the sample exceeded the standard rate of 8.16%-17.7%, including pickled vegetables, edible starch, and dried vegetables. Among them, the sulfur dioxide content exceeded the standard rate of 63.64%, 48.00%, 30.09%, and the risk quotient (HQ) was 0.464, 0.075, and 0.527, respectively. Due to the low consumption of dried vegetables, pickled vegetables, edible starch and edible fungus products, they are still at a safe level, but the cumulative effect of sulfur dioxide residues in the diet may pose health risks to consumers.


Introduction
Food safety is a major livelihood issue related to the health and life safety of the people. In the "GB 2760-2014 National Food Safety Standard Food Additives Use Standard" [1] , sulfur dioxide is widely used as a food additive in food. At the same time, China has strict regulations and management on the use of sulfur dioxide. Enshi CDC food safety risks of long-term monitoring, we found 2012--2019 Residues in the amount of sulfur dioxide in foods Enshi the standard. Active sulfur dioxide in food research and health risk assessment, providing technical support and scientific basis for long-term monitoring of food additives in Enshi.

Sample collection
A total of 714 samples were randomly collected in small restaurants, markets and stores in Enshi Prefecture, Hubei Province, China. during 2012 to 2019. The sample types included pickled vegetables, food starch, soy products, edible mushrooms, dried vegetables, nuts and seeds cereal products, etc.
According to the food safety risk monitoring manual, the sample size of each product is at least 1.0 kg. After purchase, the samples were immediately sent to a laboratory for testing after crushing [2][3] .

Analysis procedure
The sample was pulverized, mixed, uniformly 5g weighed sample into the distillation flask. Add 250mL of distilled water, install the condensing device, insert the lower end of the condensing tube into the liquid level of the iodine flask pre-prepared with 25mL of lead acetate absorption solution, then add 10mL of hydrochloric acid solution to the distillation flask, stop it immediately, heat it for distillation, about 200 mL, away from the liquid surface so that the lower end of the condensing duct, redistillation 1min, while the blank test.
To remove iodine flask were added 10mL of hydrochloric acid, 1 mL of starch indicator solution, then shake with iodine standard solution was titrated to the color of the solution turns blue and 30s do not fade, the record Iodine Titration volume of solution consumed. The standard solution of iodine titration volume, calculated content of sulfur dioxide in food analysis.

Dietary exposure assessment
Dietary exposure assessment model is mainly based on the Environmental Protection Agency released. According to the monitored sulfur dioxide residue and food consumption data, calculate the estimated daily intake of sulfur dioxide in food according to formula (1) [4][5] .

Risk quotient
The risk description of chemical hazards with thresholds is generally carried out using the risk quotient method HQ. The risk quotient (HQ) is calculated by EED and ADI according to the following formula (2).

=
(2) Where, HQ risk quotient value of all people, and ADI acceptable daily intake of sulfur dioxide. In this study, the ADI for sulfur dioxide was 0.7 mg/(kg· bw· d) set by JECFA [6] .
Its meaning is: when HQ>1, it means there is a risk, the greater the value, the greater the risk.

Maximum safe consumption
The maximum safe daily consumption (Fimax) of sulfur dioxide residue food is calculated according to the following formula (3). Where: Fimax: indicates the maximum safe daily consumption(kg/d); BW: body weight represents the crowd(kg); Ci: represents food in sulfur dioxide content(mg/kg).

Results and discussion
Similar studies on sulfur dioxide residues in fresh vegetables, edible fungi and dried fruits have been reported [7][8] . Table 1 lists the residual concentration and risk quotient of sulfur dioxide in 714 samples. In general, the average concentration of sulfur dioxide in dried vegetables, pickled vegetables, edible starch and edible fungus products are higher than the MRLs(Dried vegetables, pickled vegetables, food starch and edible fungi articles sulfur dioxide limits were 200, 100, 30 and 50 mg / kg), and the risk quotient (HQ) is 0.527, 0.464, 0.075, and 0.025, respectively. Due to the low consumption of dried vegetables, pickled vegetables, edible starch and edible fungus products, they are still at a safe level, but the cumulative effect of sulfur dioxide residues in the diet may pose health risks to consumers. These results are consistent with previous research results. In terms of sample sampling, Table 2 shows that samples with excess sulfur dioxide are mainly from small restaurants, farmer's markets and shops, and their excess rates are 16.86%, 11.11%, and 6.45%, respectively. These places are where local people mainly buy food. For sulfur dioxide residues in food, we calculated according to the formula (3), adult day dried vegetables, pickled vegetables and other foods, the maximum safe intake does not exceed 0.21 kg, 0.42 kg, 0.84kg. However, when the residual sulfur dioxide in dried vegetables is 2170mg/kg, the safe daily intake is only 0.019kg.
Sulfur dioxide as a food additive, because of having a bleaching action, antioxidant and preservation, food preservation which is widely used in the food production process. Because the children in the formative years, a variety of food demand, sulfur dioxide dietary exposure risk is greater. Therefore, sulfite overuse and misuse may have potential adverse effects on human health.
In this exposure assessment process, we assume that processed foods factors, edible part of the factor, gastrointestinal absorption coefficient are less 1 part of the sample number, representativeness is not strong, which give exposure assessment of sulfur dioxide added to the uncertainty.

Conclusions
This study provides Enshi sulfur dioxide residues in food risk assessment to the general population. According to the "GB 2760-2014 Food Safety National Standards for the Use of Food Additives", the excess rate of sulfur dioxide samples in different food categories varies greatly. Among them, pickled vegetables, edible starch, and dried vegetables have the highest sulfur dioxide content, which is 63.64%, respectively. The risk quotient (HQ) of 48.00% and 30.09% were 0.464, 0.075 and 0.527 respectively. Due to the low consumption of pickled vegetables, edible starch and dried vegetables, they are still at a safe level, but the cumulative effect of sulfur dioxide residues in the diet may pose health risks to consumers.
In order to prevent people, especially children in the diet overexposure sulfur dioxide, it is still necessary to reduce and limit the use of sulphites and sulfur dioxide by law enforcement activities, and called for tighter regulation of public education and implementation of integrated management additive method, Ensure food safety.