Mycotoxins in Fermented Food1
Total Page：16
File Type：pdf, Size：1020Kb
[CANCER RESEARCH 28, 2296-2311, November 1968] Mycotoxins in Fermented Food1 R. Kinosita, T. Ishiko, S. Sugiyama, T. Seto, S. Igarasi, and I. E. Goetz City of Hope Medical Center, Duarte, California 91010 SUMMARY The biometrie statistics in Japan are quite reliable. The whole population is over 100 million, large enough to offer Selected for study fields were several distinct provincial reliable statistic figures. Moreover, practically all the people regions of Japan which are noted to be stable in population are of the same race, similar in habit and custom, literate, and composition, generally conservative in the mode of life, and live close to each other on the small well-developed land. distinguished by especially high figures in biometrie statistics Practically no one is left out of the official registration and representing the Japanese characteristics of extraordinarily census. According to a recent report issued from the Depart high incidence in death by cardiovascular diseases, stomach ment of Statistical Investigation, Japanese Ministry of Health cancer, and hepatoma. From these regions, samples of popular (Japanese Medical News, No. 2282, p. 108, 1968), the three fermented foodstuffs, consumed daily in quantity, were ob tained as materials of study. They included "miso" or fer highest causes of death in 1967 in Japan were apoplexy, mented soy bean paste, "katsuobushi" or fermented dry neoplasms, and heart diseases in that order, or more precisely, bonitos, and "starters" used for their fermentation processes. 25.6, 16.7, and 11.0 percent of the total death cases (about 670,000) respectively. The percentage of total death cases by They were either commercial products from local plants or cardiovascular diseases, including those by apoplexy and by home-made ones. From 24 samples, 37 strains of fungi were hypertension, was as high as 39.3 percent. Compared with the isolated, of which 21 were found to produce toxic culture 1966 figures, the total death cases by cardiovascular diseases filtrates and extracts. Many of them produced kojic acid and were higher, especially so in heart diseases, but those for ß-nitropropionic acid. None, however, produced aflatoxin, apoplexy were slightly decreased. The death cases by neo although some strains produced blue and green fluorescent plasms were generally increased, except for those by uterine metabolites which have not yet been identified. Biologic tests cancer. Of neoplasms, stomach cancer and hepatoma still carried out with the culture preparations revealed significant remained leading the list. It was remarkable, however, that biologic activities in bacteriocidal effects, induction of bacteri- hepatoma showed a slight decline in the rural areas, where ophage, and influence on propagation of hamster cells in vitro. various environmental conditions including daily food were Moreover, short-term animal experiments showed development considerably changing. Thus, an approach was suggested from of miscellaneous remarkable pathologic changes, such as exten the epidemiologie angle to study prevailing environmental sive hemorrhagic erosion in the glandular stomach, necrosis in noxae, especially the popular but possibly injurious foodstuffs, the liver, and injuries in the kidneys, pancreas islets, and such as fermented foodstuffs. These were represented by myocardium. The changes in the stomach and liver drew "miso" or fermented soy bean paste and "katsuobushi" or special attention in association with high incidence of chronic fermented dry bonito, consumed daily in quantity by most gastric and hepatic diseases in the biostatistics. Of the other Japanese. changes, glomerulotubular nephritis, renal tubular oxalosis, pancreas-islet hemorrhage and degeneration, and myocardial MATERIALS AND METHODS hemorrhage and scar formation were impressive in relation to the high incidence of cardiovascular diseases. To prevent Fermented foodstuffs usually are prepared by the use of a occurrence of toxic agents in fermented food, it was recom starter, namely "tane-koji," commercially obtained or indi mended to avoid the use of toxic strains of fungi and to vidually prepared in a traditional way and preserved. In fact, it eliminate contamination of undesirable strains of fungi. is a batch of dried fermented rice containing a lot of spores of fungi, usually strains of Aspergillus. INTRODUCTION For a preliminary study, tane-koji was locally obtained which had been produced in a plant in Los Angeles, probably The present investigation was undertaken to find possible originally started many years ago with imported tane-koji from noxious agents in foodstuffs prepared by fermentation, such as Japan. Pathologic effects were examined by administering to "miso" and similar foodstuffs, consumed daily and in quantity mice and rats tane-koji itself, rice gruel fermented with it, and by almost all people in Japan, and to contribute to etiologic preparations prepared from cultures in Czapek medium of A. analysis of such diseases especially high in incidence among oryzae isolated from the tane-koji (11). Since kojic acid was these people as shown by biometrie statistics. found to be a metabolite of the fungus, effects of a commer cially obtained preparation of kojic acid also were similarly investigated (10). Remarkable findings were (a) massive nec 'This study was supported by NIH Contract No. PH43-65-1036. rosis in the guinea pig liver by s.c. injections of fermented rice 2296 CANCER RESEARCH VOL. 28 Downloaded from cancerres.aacrjournals.org on October 1, 2021. © 1968 American Association for Cancer Research. Mycotoxins in Fermented Food gruel extract, (b) tubular dilatation, epithelial degeneration, oughly fermented, they are put in the sun to dry completely. and focal atypical epithelial hyperplasia with abnormal mitosis The entire procedure usually takes about 10 months. Further in the convoluted tubules in the mouse kidneys by i.p. injec more, at katsuobushi plants the removed intestines are cleanly tions of a preparation from methanol extract of A. oryzae washed with running water and fermented similarly by natural cultures, (c) focal necrosis and circumscript hyperplasia with contamination of fungi and then mixed with salt. It is a many mitotic figures in the mouse liver by i.p. injections of well-known delicious appetizer called "shuto" or "shiokara." kojic acid solution, (d) marked inhibition of the body growth Another fermented product consumed in a large quantity is and cirrhotic changes in the liver of rats by s.c. injections of "shoyu" or soy sauce. Its production has been greatly indus kojic acid solution, and (e) various abnormalities such as trialized and known cultured strains of fungi are usually used. acrania (Fig. 1), ataxia, demyelinization, and neuron degenera In small scale production at rural areas, however, wild strains tion in the midbrain, etc., in newly hatched chicks by injec are still used for starters. "Sake" or rice wine is in a similar tion of kojic acid in embrionated eggs on the 5th day of situation. In any case, the starter used by each brewery is an incubation. Furthermore, interesting findings obtained from important part of a secret formula to assure the special quality the additional experiments were (d) bile duct proliferation and and flavor for its products. A starter, therefore, is a special fibrosis in the liver of ducklings given a concentrated culture strain or a certain combination of strains. Thus, numerous filtrate of A. oryzae, and (b) asymmetric mitosis, chromosome strains of fungi are concerned with the essential process of stickiness and breaks, and reversion of mitosis in the rat liver fermentation for preparing fermented food. Often, however, cells in culture treated with kojic acid. some starters carry passenger strains, actually useless for the On the basis of these findings, the study was designed to purpose. Furthermore fungal contamination sometimes occurs. expand to an extensive scale. Katsuobushi, miso, etc., were For instance, A. tamarii has been found in soy sauce in certain sampled in several distinct provincial regions in Japan which areas of Middle Japan. It was shown in another experiment are noted to be stable in population composition, (having (unpublished) that a culture filtrate of the fungi given orally to scarcely any settlers from other regions), generally conserva C57BL/6J mice caused atypical epithelial proliferation in the tive in the mode of life, and extraordinarily high in death cases glandular stomach (Fig. 2) resembling the features often of cardiovascular diseases, stomach cancer, and hepatoma. observed in gastric biopsy specimens and described as early Miso is consumed, on the average, 32.7 gm in the country changes of stomach cancer. and 26.1 gm in towns per person every day in soups or mixed To screen harmful fermented foodstuffs in this complicated with vegetables and fish (19). It is prepared from soy beans circumstance, it was very important to plan carefully where and barley by fermentation and then mixed with a large what sorts of materials were to be sampled for the study. First, proportion of salt, in about 12 or more percent, to stop the three distinct provincial regions, namely Nara, Wakayama, and progress of fermentation for preservation. In urban areas it is Yamagata, were selected, which are noted in the nation for produced mainly at modern plants on a large scale in a more or very high figures in the death statistics of the diseases previous less scientific way by the use of selected tane-koji, prepared ly referred