Original Evaluation of Preservatives Contents in Foods and ...

June 1997 145

Original

Evaluation of Preservatives Contents in Foods and

the Daily Intake Deduced from the Results

of the Official Inspection in Japan

in F.Y. 1994

(Received January 14, 1997)

Hajlnlu ISHIWATA*1, Motohlro NISHIJIMA*2, Yoshlnobu FUKASAWA*3,

Yoshio ITO*4 and Takashi YAMADA*1

(*1National Institute of Health Sciences: 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158, Japan; *2The Tokyo Metropolitan Research Laboratory of Public Health: 3-24-1, Hyakunin-cho,

Shinjuku-ku, Tokyo 169, Japan; *3Yamanashi Institute of Public Health: 1-7-31, Fujimi, Kofu-shi 400, Japan; *4Faculty of Pharmaceutical Sciences,

Mukogawa Women's University: 11-68, Koshien Kyuban-cho, Nishinomiya-shi 663, Japan)

The concentrations of preservatives (benzoic acid, dehydroacetic acid, p-hydroxybenzoic acid esters, propionic acid and sorbic acid) in foods sold in Japan were estimated using the results of the official inspection in F.Y. 1994 by 96 local governments covering most of Japan. The total number of inspection samples was 72,609, including 4,803 imported foods. The detection rates of benzoic acid, dehydroacetic acid, p-hydroxybenzoic acid esters, propionic acid and sorbic acid in foods in which they are permitted to be used were 25.7%, 5.0%, 28.6%, 10.3% and 53.9%, respectively. The average concentrations of preservatives in all samples in which they were permitted were 8.8%, 0.7%, 8.8%, 2.8% and 16.2% of the legal maximum levels of use, respectively. Detection rates and average concentrations in nonpermissible foods were 2.9% and 0.00220 g/kg for benzoic acid, 0.021 % and 0.0000963 g/kg for dehydroacetic acid, 0.24% and 0.0000930 g/kg for p-hydroxybenzoic acid esters as p-hydroxybenzoic acid, and 5.2% and 0.0186 g/kg for sorbic acid. No propionic acid was detected in nonpermissible foods.

The estimated daily intakes of these preservatives were 11.0, 0.0769, 1.37, 3.88 and 32.9 mg/person, respectively, when calculated from the average concentrations in foods obtained in the present study, utilizing the consumption of foods reported by the "Investigation Group of the Daily Intake of Food Additives in Japan in F.Y. 1994". Foods that contributed most to the daily intake of preservatives were as follows: benzoic acid, 86.8% of the daily intake amount from nonalcoholic beverages; dehydroacetic acid, 55.7% from confectionery; p-hydroxybenzoic acid, 51.8% from soy sauce; propionic acid, 87.0% from bread; sorbic acid, 26.2% from fish paste products. The estimated daily intakes of these preservatives was less than 5% of the acceptable daily intake (ADI).

Key words: preservatives, daily intake, benzoic acid, dehydroacetic acid, p-hydroxybenzoic acid esters, propionic acid, sorbic acid, surveillance in food, standard for use, official inspection

Introduction

Acceptable daily intakes (ADIs) have been set for major food additives used in the world by the Joint FAQ/WHO Food Standard Pro-

grammes1) to ensure the safety of consumers. For many years, the "Investigation Group of the Daily Intake of Food Additives in Japan" (the

Japanese group)2)-4) funded by the Health Sci-ences Research Grants of the Ministry of Health

146 J. Food Hyg. Soc. Japan Vol. 38, No. 3

and welfare has worked to estimate dietary intake of food additives, and this work has

played an important role in the risk assessment and regulatory evaluation of food additives. The daily intake of food additives has also been investigated in the United Kingdom (UK)5. For the estimation of the daily intake of food

additives, we require data on the concentrations of food additives in foods and on the amount of food consumption. The Japanese group has employed a total diet study method (a market basket method) for the estimation of daily intake of food additives. This method was based on the determination of food additives in the mixture of foods comprising the daily consump-tion amount estimated by the Japanese group2),4). The UK group estimated the daily intake by the surveillance of the amount of food additives

produced and the amount of food additives used by food makers by means of a questionnaire.

Although there have been many reports on the determination of food additives in foods, the number of tested samples was generally not sufficient to evaluate the average concentration of food additives in foods for the estimation of daily intake. In the present paper, we estimated

the average concentrations of preservatives, benzoic acid, dehydroacetic acid, p-hydroxy-benzoic acid esters, propionic acid and sorbic acid, in commercial foods based on the data of the official inspection of foods in markets per-formed by the local governments in Japan. The estimation of the daily intake of preservatives was also described using both the official inspec-tion results and the daily consumption of pro-cessed foods reported by the Japanese group4). The concentration of sorbic acid in foods and estimation of its daily intake (using the food consumption data reported by the National Nu-trition Survey6}) were reported as preliminary findings7).

Methods

1. Investigation methods and items studied a) Questionnaire A questionnaire on the results of the official

inspection on food additives during April 1, 1994 and March 31, 1995 (F. Y. 1994) was sent to all 103 local governments of Japan from the Division of Food Chemistry, Ministry of Health and Welfare, Japan8). These local governments are obligated to establish public health centers

Table 1. Number of Local Governments that Performed Inspection of Preservatives and Number of

Inspected Food Samples

Table 2. Detection Limits of Preservatives

*1 Percentage of local governments that employed the indicated detection limit(s). *2 Percentage of samples to which the indicated detection limit(s) was applied.

June 1997 Concentration of Preservatives in Food and Daily Intake 147

by the Regional Public Health Law. b) Items The names of both imported and domestic

foods, the number of foods inspected, the number of samples in which preservatives were detected, the maximum, minimum and average concentrations of the food additives in detected samples, and the detection limit of the analysis for each preservative were recorded. The fol-lowing preservatives were investigated in the

present paper; benzoic acid (benzoic acid and sodium benzoate), dehydroacetic acid (sodium dehydroacetate), p-hydroxybenzoic acid esters

(ethyl, propyl, i-propyl, butyl and n-butyl esters) propionic acid (propionic acid, calcium pro-pionate and sodium propionate) and sorbic acid (sorbic acid and potassium sorbate). Substances in parentheses are permitted as preservatives in Japan. The concentrations of p-hydroxybenzoic acid esters were described as p-hydroxybenzoic acid and the concentrations of other preserva-tives were represented as free acid, according to the standards for use9).

c) Sampling of foods and analytical methods for preservatives

Samples (final food products) were chosen by food inspectors in markets or factories of food

producers according to the yearly programme of each local government. Gas chromatography for propionic acid10) and high performance liquid chromatography for other preserva-tives11) as directed by the Environmental Health Bureau, the Ministry of Health and Welfare, were used.

2. Analyses of reports from the local governments Reports sent from the local governments were

classified into groups of foods according to the standards for use of food additives9). Nonper-missible foods, in which preservatives are not

permitted to be used, were categorized accord-ing to the "Guide for Categorization of Food"12) Concentrations of preservatives were calculated as 0 g/kg when no preservatives were detected.

3. Calculations and daily intake estimations Daily intake of preservatives was estimated

from the average concentrations of food addi-tives in foods obtained in the present work and the daily food consumption per capita. The

daily consumption of foods was taken from a report by the Japanese group4). In the case of foods where the consumption is not known, 0.1

g was assumed as a daily consumption per person.

Results and Discussion

1. Recovery of questionnaire and number of sam-

ples Among 103 local governments, 96 govern-

ments (93.2%), covering most of Japan, i.e., 42

prefectures, 33 cities, and 21 wards, replied to the questionnaire. Preservatives were inspected by 93 governments (96.9% of the 96 govern-ments). Inspection was performed by 85 govern-ments for benzoic acid, 51 for dehydroacetic acid, 74 for p-hydroxybenzoic acid esters, 43 for

propionic acid and 92 for sorbic acid. The total number of inspected foods was 72, 609, includ-ing 4, 803 imported foods (Table 1). Results obtained in the present studies were therefore considered to be highly reliable, since they cov-ered most areas of Japan and large numbers of samples were tested.

2. Detection limits The detection limits of these preservatives are

summarized in Table 2. About a half of the local

governments set the detection limit at 0.01 g/ kg, and more than 80% of the governments set it between 0.005 and 0.05 g/kg not including

propionic acid. Almost the same tendency on the detection limit was also observed in num-bers of inspected samples. The most common detection limit of propionic acid was 0.01 g/kg

(35.7% of the local governments and 32.5% of samples), but the limits were scattered com-

pared to those for other preservatives. The detection limit may differ depending on the food, although a narrow range of the detection limits among local governments for the same food is obviously desirable in an official inspec-tion.

3. Concentrations of preservatives in foods Preservatives were detected in 19,730 samples

out of a total of 72,609 (27.2%) samples. Concen-trations of each preservative in foods are shown in Tables 3 to 6. The results for sorbic acid have been reported in detail in the previous paper7).


a) Benzoic acid Benzoic acid was detected in 1,122 out of

13,944 samples (8.0%) (Table 3). The detection rate in tested foods in which benzoic acid was

permitted to be used was 25.7%, and the aver-age concentration of benzoic acid was 8.8% of the allowable limit according to the Food Sani-tation Law9). The highest detection rate (71.4%) was observed in caviar. The average concentra-tion in tested caviar was 0.710 g/kg, and was 28.4% of the allowable limit (2.5 g/kg). No ben-zoic acid was detected in any inspected samples

(25 samples) of margarine, in which it is allowed to be used at a maximum level of 1.0 g/kg.

Benzoic acid was detected in 312 out of 10,790 samples (2.9%) in which the compound is not permitted to be used (nonpermissible foods), such as fermented milk (25.0% of inspected sam-

ples) and dried fruits (17.2%) at an average con-centration of 0.00220 g/kg. Fermented milk13),14) and dried fruits14),15) are known to contain natu-rally occurring benzoic acid. No benzoic acid was detected in fish paste (1,345 samples), sweet-ened bean paste (222), fruit wines (202), fer-mented soybean paste-pickled foods "Miso-zuke" (70), noodles (56), and several other foods

in which the compound is not permitted to be used.

Table 3. Concentration of Benzoic Acid in Foods

* Nonpermissible foods in which benzoic acid was detected.


b) Dehydroacetic acid Dehydroacetic acid was detected in 26 out of

9,828 samples (0.3%) (Table 4). The detection rate in all foods in which the use of sodium dehydroacetate is allowed was 5.0%, but the compound was detected only in cheese (24 out of 429 samples (5.6%)). The average concentra-tion in cheese was 0.0104 g/kg, and was 2.1% of the allowable limit (0.50 g/kg). Dehydroacetic acid was detected at the concentration of 0.45 g/ kg in 2 samples out of 1,001 samples (0.2%) of confectionery (Kashi), a food in which sodium dehydroacetate is not permitted to be used, while the average concentration was 0.000899

g/kg in all samples of confectionery. No dehy-droacetic acid was detected in the following nonpermissible foods: fish paste (1,218 samples), various pickles (1,207), meat products (532), cooked foods "Sozai" (367), foods boiled down in soy sauce "Tsukudani" (316), sweetened bean

paste "An" (287), non-alcoholic beverages (271), fermented soybean paste "Miso" (270) and sever-al other foods.

c) p-Hydroxybenzoic acid esters Ethyl, propyl, i-propyl, butyl and n-butyl

esters of p-hydroxybenzoic acid are allowed as food additives in Japan9), and the limits of these esters are regulated as the total amount of p-

and Estimated Amount of Daily Intake


hydroxybenzoic acid.

p-Hydroxybenzoic acid esters were detected in 903 out of 9,876 samples (9.1%) (Table 5). The detection rate and average concentration in all foods in which these are allowed to be used were 28.6% and 8.8% of the limits, respectively. The highest detection rate among the foods permit-ted to use the compounds was in soy sauce

(49.8%), and the average concentration in all

tested soy sauce samples was also the highest; 0.0342 g/kg as p-hydroxybenzoic acid. This concentration corresponded to 13.7% of the per-missible limit. p-Hydroxybenzoic acid esters were detected in 16 out of 6,775 samples (0.24%) of foods in which the esters are not permitted to be used, and the average concentration was 0.0000930 g/kg asp-hydroxybenzoic acid. Most were foods seasoned with soy sauce, and the

Table 4. Concentration of Dehydroacetic Acid in

* Nonpermissible foods in which dehydroacetic acid was detected.

Table 5. Concentration of p-Hydroxybenzoic Acid

* Nonpermissible foods in which p-hydroxybenzoic acid esters were detected.


concentrations of the esters in detected samples except processed soy sauce were less than 1/5 of that observed in soy sauce. No p-hydroxy-benzoic acid esters were detected in the follow-ing nonpermissible foods; various pickles (1,077 samples), fish paste (679), confectionery (585), meat products (359), foods boiled down with soy sauce "Tsukudani" (270), soybean paste (162), boiled beans (155), and several other foods.

d) Propionic acid Propionic acid was detected in 82 out of 828

samples (9.9%) (Table 6). The highest detection rate (18.8%) was observed in bread. The aver-age concentration of propionic acid was the high-est in cheese (0.104 g/kg), but the ratio to the

permissible limit was the highest in bread (3.6% of the limit). The detection rate and average concentration in all foods in which Propionic

Foods and Estimated Amount of Daily Intake

Esters and Estimated Amount of Daily Intake


acid is permitted were 10.3% and 2.8% of the limit, respectively. No propionic acid was detec-ted in 29 nonpermissible foods, such as confec-tionery other than cakes.

e) Sorbic acid Detailed results have been reported in the pre-

vious paper7). Sorbic acid was detected in 17,597 out of 38,133 (46.1%) tested samples. The aver-age concentration of sorbic acid in permitted foods that used it was 16.2% of the permissible limit. Sorbic acid is permitted to be used in a wider variety of foods than other preservatives, and four kinds of preservatives other than pro-

pionic acid can be determined by a simultaneous analytical method11). The number of nonper-missible foods inspected for benzoic acid, dehy-droacetic acid and p-hydroxybenzoic acid esters was therefore higher than that in the case of sorbic acid.

4. Evaluation of preservative concentrations in

foods The concentrations of preservatives shown in

Tables 3-6 might be inadequate for the estima-tion of daily intake of preservatives due to over-or underestimation for the reasons described below.

(a) Most samples inspected were foods in which preservatives are permitted to be used.

(b) Many foods in which preservatives are not permitted were also inspected, and most of them were perishables such as foods boiled down in soy sauce (Tsukudani) and soy sauce-

pickled foods (Shoyu-zuke) for benzoic acid, con-fectionery for dehydroacetic acid, pickles (Tsu-kemono) for p-hydroxybenzoic acid esters, and

cooked foods (Sozai) for sorbic acid. Sampling in the official inspection is basically done for foods in which food additives are permitted to be used and nonpermissible foods in which food addi-tives might be used. Therefore, if foods in which food additives are probably not used were chosen at random for the inspection, the detec-tion rates and the mean concentration may be lower than the present results.

(c) Foods containing excessive amounts of preservatives and nonpermissible foods contain-ing preservatives (except those present by carry-over) at the levels more than the detection limits would be excluded from markets by the local

governments. The present results shown in Tables 3-6 includes these foods which would be banned from sale.

(d) Concentrations of preservatives in foods in which they were not detected was calculated as 0 g/kg. Some foods may contain small amounts of these preservatives naturally or by carryover at levels lower than the detection limits.

Among these factors affecting the mean con-centration of preservatives, (a), (b) and (c) may result in overestimation and (d) may be a cause of underestimation. The factors (a) and (b) would most strongly affect the results. It is therefore more likely that the results obtained in the present study are overestimated rather than underestimated.

5. Estimation of daily intake of preservatives per

person The daily intake of food additives has been

estimated by means of the market basket method2)-4) and a questionnaire to food and food

Table 6. Concentration of Propionic Acid


additive producers5). We employed another method. Daily intake of preservatives was es-timated based on the concentrations of preserv-atives obtained in the present studies and data on the daily amounts of foods consumed as es-timated by the Japanese group4). The group estimated that 767.9 g of processed foods are consumed per person per day in Japan. Esti-mated amounts of daily intake of preservatives are as follows: benzoic acid, 11.0 mg; dehydro-acetic acid, 0.0796 mg; p-hydroxybenzoic acid esters as p-hydroxybenzoic acid, 1.37 mg; propi-onic acid, 3.88 mg; and sorbic acid, 32.9 mg

(Table 7). These daily intakes of preservatives might be overestimated or underestimated as discussed above. Foods that contributed most to the daily intake were nonalcoholic beverages

(86.8% of daily intake of benzoic acid), confec-tionery (55.7% of dehydroacetic acid), soy sauce

(51.8% of p-hydroxybenzoic acid), bread (87.0% of propionic acid), and fish paste products

(26.2% of sorbic acid). The estimated daily in-takes of preservatives in the present investiga-

tion correlated fairly well with previous re-

ports4),5),16) However, that of p-hydroxybenzoic acid was about 10 times higher than the amount reported by the Japanese group4) and the UK

groups), and that of benzoic acid was about 1/4 of that reported by the UK group. The cause of the difference of daily intake of p-hydroxy-benzoic acid is not clear, since the major source in the report by the Japanese group4) was "food category I", consisting of beverages and sauce including soy sauce, as in the present case. These results are shown in Table 7, together with the reported results 4),5),16) and the ADI1). In the case of dehydroacetic acid, the contribution rate of confectionery, a nonpermissible food, was higher than that of cheese. The category of confectionery in Japan includes a variety of foods12), so that the daily consumption of confec-tionery is high, 49.3 mg per person4). Dehydro-acetic acid was detected in only two samples among 1,001 samples of confectionery, so the daily intake of dehydroacetic acid and the con-tribution rate of confectionery may be extreme-

and Estimated Amount of Daily Intake

Table 7. Estimated Daily Intakes of Preservatives and Ratios to ADI

*1 Total of esters

*2 Recalculated using the new data41 for the amount of food consumption


ly low. Ratio to the ADI of daily intake of benzoic

acid was the highest (4.4%), and those of sorbic acid and p-hydroxybenzoic acid were 2.6% and 0.3%, respectively. ADI of propionic acid is not limited, and that of dehydroacetic acid is not evaluated.

The daily intake of sorbic acid was previously estimated as 29.0 mg/person7) based on the daily consumption of foods reported by the Na-tional Nutrition Survey6). Classifications of foods in the National Nutrition Survey6) and by the Japanese group4) are quite different. The daily intake of foods in the former are classified from the viewpoint of nutrition, and the varie-ties of processed foods are insufficient for our

purpose. On the other hand, grouping of the foods by the latter followed the standards for the use of food additives9), and the daily con-sumptions of 150 processed foods were listed. Therefore the reliability of the estimated daily intake of sorbic acid in the present paper (32.9 mg/person) based on the report by the Japanese

group4) might be higher than that of the previ-ous estimate (29.0 mg/person), which was based on the National Nutrition Survey6).

Acknowledgments

We are indebted to the Division of Food Chemistry, Ministry of Health and Welfare, and local governments for cooperating with this survey. A part of this work was supported by "Health Science Research Grants, 1996" from the

Ministry of Health and Welfare.

References

1) Japan Food Additives Association: "Food Addi-tives Manual", p. 259-290 (1995) Japan Food Additives Association, Tokyo.

2) Ito, Y. ed., Ministry of Health and Welfare, Japan, supervised: "Daily intake of food addi-tives in Japanese, 1976-1985" (1988) Shakai-hoken Shuppan, Tokyo.

3) Yada, T., et al.: Jpn. J. Food Chem. 2, 54-63

(1995). 4) Investigation Group of the Daily Intake of Food

Additives in Japan: "Daily intake of food addi-tives in Japanese", Report of the Health Sciences Research Grants (1994).

5) Ministry of Agriculture, Fisheries and Food, UK: "Dietary intake of food additives in the UK: Initial surveillance", Food Surveillance Paper No. 37 (1993) Her Majesty's Stationary Office, London.

6) Ministry of Health and Welfare: "National Nu-trition Survey", p. 88-89 (1993).

7) Ishiwata, H., Nishijima, M., Fukasawa, Y., Ito, Y., Yamada, T.: J. Food Hyg. Soc. Japan 37, 378-384 (1996).

8) Division of Food Chemistry: "Inspection results of food additives in foods (trust)", Ei-Ka No. 114, September 26 (1995).

9) Ministry of Health and Welfare: "The Japanese Standards for Food Additives", 6th Ed., English version, p. 634-668 (1994), Tokyo.

10) Ed. by the Environmental Health Bureau, Min-istry of Health and Welfare: "Guide for Food Sanitation Inspection-Analytical Methods for Food Additives in Foods", p.14-35 (1989) Japan Food Hygiene Association, Tokyo.

11) Ed. by the Environmental Health Bureau, Min-istry of Health and Welfare: "Guide for Food Sanitation Inspection-Analytical Methods for Food Additives in Foods, Supplement I", p. 335-342 (1993) Japan Food Hygiene Association, Tokyo.

12) Japan Food Additives Association: "Guide for Categorization of Food" (1995) Japan Food Ad-ditives Association, Tokyo.

13) Hatanaka, H., Kaneda, Y.: J. Food Hyg. Soc. Japan 27, 81-86 (1986).

14) Nagayama, T., Nishijima, M., Yasuda, K., Saito, K., Kamimura, H., Ibe, A., Ushiyama, H., Naoi, Y., Nishima, T.: ibid. 27, 316-325 (1986).

15) Nagayama, T., Nishijima, M., Yasuda, K., Saito, K., Kamimura, H., Ibe, A., Ushiyama, H., Naga-

yama, M., Naoi, Y.: ibid. 24, 416-422 (1983). 16) Investigation Group of the Daily Intake of Food

Additives in Japan: "Daily intake of food addi-tives in Japanese", Report of the Health Sciences Research Grants (1995).

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