February (Received September 1, 1999)

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1 February Report Estimation of Inorganic Food Additive (Nitrite, Nitrate, and Sulfur Dioxide) Concentrations in Foods and Their Daily Intake Based on Official Inspection Results in Japan in Fiscal Year (Received September 1, 1999) Hajimu ISHIWATA*1, Taklko SUGITA*1, Yoko KAWASAKI*1, Yuiko TAKEDA*1, Takashi YAMADA*1, Motohlro NISHIJIMA*2 and Yoshlnobu FUKASAWA*3 (*lnational Institute of Health Sciences: , Kamiyoga, Setagaya-ku, Tokyo , Japan; *2The Tokyo Metropolitan Research Laboratory of Public Health: , Hyakunin-cho, Shinjuku-ku, Tokyo , Japan; *3Yamanashi Institute of Public Health: , Fujimi, Kofu-shi , Japan) Mean concentration and daily intake of the inorganic food additives nitrite, nitrate, and sulfur dioxide were estimated based on the analysis of 15,569 samples of food obtained at official inspections by Japanese local governments in fiscal year The mean concentration of nitrite was 17.2% of the allowable limit, and those of nitrate and sulfur dioxide were 30.9% and 14.4%, respectively. Daily intakes of these inorganic food additives per person, estimated from the concentrations and daily consumption of the foods, were 1.07, 1.43, and 1.45 mg, respectively. These amounts of nitrite, nitrate, and sulfur dioxide were 35.7%, 0.8%, and 4.1% of the acceptable daily intakes (ADIs), respectively, when body weight was assumed to be 50kg. Ratios to ADI were similar to those based on the results of the official inspection in fiscal year 1994 except that nitrite intake in fiscal year 1994 was 10.6% of the ADI. The major reason for the increase of the calculated daily intake of nitrite in fiscal year 1996 was that 0.020g/kg nitrite, corresponding to a daily intake of 0.87mg, was found in confectionery, a food category which was not inspected in fiscal year Key words: food additive; concentration in food; daily intake; nitrite; nitrate; sulfur dioxide; sulfite; official inspection Introduction Estimates of the daily intake of 16 food additives based on the results of official inspection in Japan in fiscal year 1994 have been reported15). The same surveillance study on the same 16 food additives based on official inspections in fiscal year 1996 was repeated, and the estimated daily intake of preservatives and antifungal agents in fiscal year 1996 were reported6) 7). In the present study, we estimated the mean concentrations in foods of three inorganic food additives (nitrite, nitrate, and sulfur dioxide) which are allowed as food additives in Japan, and deduced the daily intakes of these inorganic food additives per person from the mean concentrations and amounts of food consumed. Concentration of Food Additives in Foods and the Daily Intake in Japan (Report No. 7)[Report No. 6 was entitled "Estimation of Antifungal Agents Concentrations Allowed as Food Additives in Food and Their Daily Intake Based on Official Inspection Results in Japan in Fiscal Year 1996", published in this Journal, 40, (1999).] Methods The methods used were the same as those previously described),2),4) but this time the results of official inspections performed in fiscal year 1996 were used. 1. Investigation methods and items studied a) Questionnaire A questionnaire concerning the results of official inspections for food additives from April 1,1996 to March 31, 1997 (Japanese fiscal year 1996) was sent by the Division of Food Chemistry, Ministry of Health and Welfare of Japan8) to all 108 local governments which are obliged to establish public health centers by the Regional Public Health Law. b) Items queried The following inorganic food additives were investigated in this study: nitrite (sodium nitrite), nitrate (sodium nitrate and potassium nitrate), and sulfur dioxide (sodium sulfite, sodium hydrosulfite, sulfur dioxide, potassium pyrosulfite, sodium pyrosulfite, potassium hydrogen sulfite solution, and sodium hydrogen sulfite

2 80 J. Food Hyg. Soc. Japan Vol. 41, No. 1 Table 1. Number of Local Governments That Performed Inspection of Inorganic Food Additives and Number of Food Samples Inspected solution). The substances in parentheses above are permitted as food additives in Japan. The concentration of sulfites was expressed as sulfur dioxide in accordance with the Japanese Standards for Use of Food Additives9). The names of both imported and domestic foods, the numbers of food samples inspected, the numbers of samples in which these inorganic food additives were detected, the maximum, minimum, and mean concentrations detected in the samples, and the detection limit of the analysis for each inorganic food additive were recorded. c) Sampling of foods and analytical methods for inorganic food additives In accordance with the annual program of each local government, samples were chosen by food inspectors in markets or in factories manufacturing food products. Colorimetry was used to analyze nitrite, colorimetry after cadmium column reduction for nitrate, and the alkaline titration method or colorimetry after distillation for sulfur dioxide, all as recommended by the Environmental Health Bureau of the Ministry of Health and Welfarelo) 2. Analyses of reports from local governments Data sent from the local governments were classified according to the categories of foods in the Japanese Standards for Use of Food Additives9). Foods in which these compounds are not allowed were categorized according to the Guide for Categorization of Foodll) Concentrations of these inorganic food additives, as in previous papersl),2),4) were regarded as 0mg/kg when they were below the detection limit. 3. Calculations and estimation of daily intake The daily intakes of the inorganic food additives per person were estimated based on the mean concentrations of these additives in all foods (including nonpermissible foods) obtained in the present study, and the daily food consumption levels reported by the Investigation Group of the Daily Intake of Food Additives in Japan (Japanese group)12) and the Ministry of Health and Welfare13). When the consumption level of a food was unknown, 0.1g was assumed to be the daily consumption per person, as described in the Food Chemistry Division Report Series14) published by the Ministry of Health and Welfare, and in previous papers)2),4); Results 1. Questionnaire return and number of samples One hundred local governments out of the 108 (92.6%, i.e., 43 prefectures, 34 cities, and 23 wards), representing most of Japan, replied to the questionnaire. Nitrite, nitrate, and sulfur dioxide were inspected by 97 local governments (97.0% of the 100 local governments which replied). Inspection was performed for nitrite by 90 local governments, for nitrate by 8 local governments, and for sulfur dioxide by 96 local governments. The total number of food samples inspected for these inorganic food additives was 15, 569, of which 2,731 (17.5% of total samples) were imported (Table 1). The total sample number in 1996 was 95.9% of that in 19944). The results obtained in the present study, except for nitrate, were therefore considered to be highly reliable, since inspection results were received from most of the local governments countrywide in Japan, and large numbers of samples were tested. 2. Concentrations of inorganic food additives Inorganic food additives nitrite, nitrate, and sulfur dioxide were detected in 6,610 (42.5%) out of a total of 15,569 food samples. Concentrations of each inorganic food additive are shown in Tables 2 to 4. a) Nitrite Nitrite was detected in 4,248 (73.5%) out of 5,777 samples tested (Table 2). The detection rate in the tested samples in which nitrite is allowed to be used was 75.9%, and the mean concentration of nitrite was 17.2% of the limits allowed by the Japanese Food Sanitation Law. The highest detection rate, 83.3%, was observed in fish meat ham (10 out of 12 samples), but the mean concentration in tested fish meat ham was 0.004g/kg, 7.5% of the allowable limit (0.050 g/kg). The concentration of nitrite in meat products was g/kg, corresponding to 17.2% of the allowable limit (0.070g/kg). The highest concentration rate relative to the allowable limit (33.3% of the limit) was observed in salted salmon ovary "sujiko". Nitrite is known to be a natural component, so low nitrite levels are considered to represent the natural component. Confectionery was not inspected in fiscal year 19944), but 20 samples were inspected in fiscal year 1996, and 0.020g/kg of nitrite was found. No nitrite was detected in meat (flesh) (12 samples), dried marine products (5), nonalcoholic beverages (3), etc.

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6 84 J. Food Hyg. Soc. Japan Vol. 41, No. 1 Table 5. Estimated Daily Intake of Inorganic Food Additives and Ratios to ADI Results in reference 4 were obtained by the same method as in the present paper based on the official inspection results in fiscal year Results in references 15 and 18 were obtained from production or usage amount, and those in reference 16 were obtained by a market-basket method. Results in reference 17 were obtained by a similar method to that of the present study. b) Nitrate Nitrate was detected in 147 out of 209 samples (70.3%) (Table 3). The number of samples tested in fiscal year 1994 was The detection rate in all foods in which the use of nitrate is allowed was 78.1%. The mean concentration in meat products was g/kg, corresponding to 85.5% of the allowable limit (0.070g/kg). No whale meat bacon was inspected in fiscal year Nitrate was detected in 43 out of 72 samples of salted pollack roe "tarako" (59.7%), in which the use of nitrate is not allowed, and the mean concentration of tested samples was g/kg. c) Sulfur dioxide Sulfur dioxide was detected in 2,215 out of 9,583 samples (23.1%) (Table 4), and the mean concentration was 14.4% of the allowable limit. The highest detection rate (96.4%) was observed in wine (514 out of 533 samples). Sulfur dioxide was also detected in a high percentage of kon-jak flour "kon'nyaku-ko" (95.3%) and dried gourd strips "kampyo" (95.1%), and the mean concentrations in tested samples were 51.8% and 33.4%, respectively, of the legal residual limits (0.90 and 5.0g/kg). Both of these foods are ingested after processing: dried gourd strips are eaten after rinsing with water and boiling with bouillon of soy sauce, and konjak flour is an ingredient of devil's tongue "kon'nyaku". One sample of starch syrup out of 10 samples contained 1.00g/kg sulfur dioxide, 5 times higher than the allowable limit (0.20g/kg), but the mean concentration in all tested samples was 50.0% of the limit. The detection rate of sulfur dioxide in "other foods" was 12.3% (detected in 831 out of 6,775 samples tested), and the mean concentration was less than g/kg, corresponding to 0.1% of the limit (0.030g/kg). No molasses or tapioca starch was inspected in fiscal year No sulfur dioxide was detected in 11 samples of sesame and one sample of beans, foods in which it is not allowed. 3. Estimation of the daily intake of inorganic food additives per person The daily intake of the three inorganic food additives was estimated based on both the concentrations of inorganic food additives obtained in the present study and the daily consumption rate of foods as estimated by a Japanese group12) and the Ministry of Health and Welfare13) The estimated daily intake of inorganic food additives per person was as follows: nitrite, 1.07mg; nitrate, 1.43mg; and sulfur dioxide, 1.45mg. These daily intakes are 35.7%, 0.8%, and 4.1%, respectively, of the acceptable daily intakes (ADIs) when body weight is assumed to be 50kg. The estimated daily intakes of nitrite in the present study, 1.07mg per person, corresponding to 35.7% of the ADI, was higher than that based on fiscal year The estimated daily intakes of inorganic food additives based on the official inspection in fiscal year 1996 are summarized in Table 5, together with the results reported in the previous paper based on the official inspection in fiscal year 19944, those reported in comparative references15-18), and the ADIs19. Discussion The concentrations of the three inorganic food additives in foods and their estimated daily intake based on official inspections by local governments in Japan in fiscal year 1994 have been reported earlier4). The same investigation was repeated using the results of official inspections in fiscal year The sample number of inspections of nitrate was almost the same as the inspection in fiscal year 1994, but was still small compared with that of other food additives27). The estimated daily intake of nitrate is therefore less reliable than those of the other food additives. The estimated daily intakes of these inorganic food additives per person were 1.07, 1.43, and 1.45mg, corresponding to 35.7%, 0.8%, and 4.1% of the ADIs, respectively. These results are similar to those obtained in the previous report4), except for the value of 35.7% of ADI for nitrite in the present study. The major source of nitrite in the present study was confectionery, from which 0.87mg (80.6% of total intake) of nitrite was ingested. Nitrite in confectionery was not inspected in fiscal year 1994, and is probably a natural component in ingredients such as flour or processed fruits. The estimated daily intake of nitrate by a market-basket method in Japan was 39.6 mg15) or mg16) per person. The results obtained by the market-basket method include nitrate in vegetables, but the estimation based on the official inspection does not include vegetables because they are not required to be inspected. Nitrate found in inspected foods may be

7 February 2000 Concentration of Inorganic Food Additives in Food and Daily Intake in F. Y mainly that which is a food additive, because most samples tested were meat products and salted pollack roe. The nitrate results reported in Finland17), 6.4mg, were obtained by a similar method to that used in the present paper, but included vegetable nitrate. The estimated daily intakes of inorganic food additives reported in the present paper include both overand underestimation factors, as discussed in the previous papersl2), 4). The biggest underestimation factor is that the results do not include natural components. These inorganic food additives are known to be natural food components as well, such as nitrate in vegetables. The estiimated intakes in the present paper may represent artificially added amounts, except for some food samples such as confectionery. Accumulation of results achieved by different methods, and the repetition of studies by the same method, are required to estimate more accurately the daily intake of food additives. Acknowledgments We are indebted to the Division of Food Chemistry, Ministry of Health and Welfare, and local governments for cooperating with this survey. This work was partly supported by the "Health Science Research Grants, 1998 and 1999, Research on Environmental Health" from the Ministry of Health and Welfare. References 1) Ishiwata, H., Nishijima, M., Fukasawa, Y., Ito, Y., Yamada, T., Evaluation of sorbic acid contents in foods and the daily intake deduced from the results of official inspection in Japan in F. Y Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 37, (1996). 2) Ishiwata, H., Nishijima, M., Fukasawa, Y., Ito, Y., Yamada, T., Evaluation of preservatives contents in foods and the daily intake deduced from the results of the official inspection in Japan in F. Y Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 38, (1997). 3) Ishiwata, H., Nishijima, M., Fukasawa, Y., Ito, Y., Yamada, T., Evaluation of the contents of antifungal agents allowed as food additives in foods and the daily intake deduced from the results of the official inspection in Japan in fiscal year Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 38, (1997). 4) Ishiwata, H., Nishijima, M., Fukasawa, Y., Ito, Y., Yamada, T., Evaluation of the inorganic food additive (nitrite, nitrate and sulfur dioxide) content of foods and estimation of daily intake based on the results of official inspection in Japan in fiscal year Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 39, (1998). 5) Ishiwata, H., Nishijima, M., Fukasawa, Y., Ito, Y., Yamada, T., Evaluation of the contents of BHA, BHT, propylene glycol, and sodium saccharin in foods and estimation of daily intake based on the results of official inspection in Japan in fiscal year Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 39, (1998). 6) Ishiwata, H., Sugita, T., Kawasaki, Y., Takeda, Y., Yamada, T., Nishijima, M., Fukasawa, Y., Estimation of preservative concentrations in food and their daily intake based on official inspection results in Japan in fiscal year Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 40, (1999). 7) Ishiwata, H., Sugita, T., Kawasaki, Y., Takeda, Y., Yamada, T., Nishijima, M., Fukasawa, Y., Estimation of antifungal agent concentrations allowed as food additives in food and their daily intake based on official inspection results in Japan in fiscal year Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 40, (1999). 8) Notification Ei-Ka No. 155 (Oct. 30, 1997), "Inspection results of food additives in foods (request)." Director of the Division of Food Chemistry, Ministry of Health and Welfare, Japan. 9) The Japanese Standards for Food Additives, 7th Ed., Ministry of Health and Welfare, Japan, 1999, p ) Environmental Health Bureau, Ministry of Health and Welfare, Japan, supervised. 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Shokuhin Eiseigaku Zasshi (J. Food Hyg. Soc. Japan), 37, (1996). 17) Penttila, P.-L., Salminen, S., Niemi, E., Estimation on the intake of food additives in Finland. Z. Lebensm. Unters. Forsch., 186, (1988). 18) Ministry of Agriculture, Fisheries and Food, UK, ed., "Dietary intake of food additives in the UK", Food Surveillance Paper, No. 37, London, Her Majesty's Stationery Office, ) Japan Food Additives Association, ed., "Shokuhintenkabutsu Manyuaru (Food additives manual)", Tokyo, Japan Food Additives Association, p , 1997.