Tetuo Tomiyama

A STUDY ON CHANGE IN NUCLEOTIDES OF MUSCLE OF WRASSE KEPT IN CHILL-STORAGE

Data presented here showed that the degradation pattern of varying nucleotides in muscle of wrasse, Pseudolabrus japonicas, kept at 0°C somewhat differed from that of carp1). ATP decreased quite rapidly as compared with that in carp muscle. A complete degradation of ATP occured approximately a three-hour period after slaughter, which corresponded to 1/20 to 1/30 of the time required for ATP degradation in carp muscle. While nearly no rigor mortis was detected in carp muscle during the chill-storage1), a quite marked rigor mortis was detected in the wrasse muscle at three-hour period of storage, accompanied with the rapid disappearance of ATP and the accumulation of considerable amount of AMP. Not much difference was noted between wrasse and carp muscle in the time of maintain-ing of maximal amount of IMP. The time of keeping passable flavor-quality was found about a half the time of incipient spoilage.

HEAT INACTIVATION OF TYLOSIN INCLUDED IN MUSCLE TISSUE AND METHOD OF ITS PREVENTION

TOMIYAMA et al2) reported previously that tylosin could be heat-inactivated both in solution and in tissues by ferric iron and/or autoxidized oil and be prevented from its inactivation by the addition of isoamylgallate and chelating agents. YOKOSEKI et al3), however, pointed out a possibility that the decrease in tylosin on heating various tylosin-containing muscle tissues might be due to the adsorption of tylosin on protein coagulum. The present data clearly indicated that tylosin included in fresh muscle tissue could be inactivated upon heating by the reaction with reducing group(s), most probably sulfhydryl group in situ or formed on heating the tissue (Tables 2, 10 and 11). This type of inactivation was inhibited by the presence of oxidizing agents (Tables 7 and 8). A possibility of leaving some tylosin activity adsorbed on protein coagulum of muscle tissue can be eradicated by the present result showing that an added amount of tylosin was nearly completely recovered in a non-coagulable part of the tissue by heating it with potassium bromate at pH 7 (Table 12).

INACTIVATION OF CHLORTETRACYCLINE IN MUSCLE TISSUE AND METHOD FOR ITS STABILIZATION

The stability of tetracyclines in muscle tissue at lower temperatures has been studied by WEISER et1), TARR et al2), WALKER and AYRES3), and TOMIYAMA et al 4-6). No concordant results, however, have been reported so far. The present authors studied on factors governing the stability of CTC in mackerel flesh brei, and revealed that two modes of inactivation were involved, namely, one occurred shortly after the addition of CTC, and the other during storage. It was found that the former could be inhibited by the inclusion of chelating agents and the latter by the presence of antioxidants (Tables 2 and 3). These protective substances, however, did not prevent CTC in a buffered solution from deterioration at 100°C (Fig. 1). It was observed that residual CTC after a 3-day icing appeared to become stabilized (Fig. 2). This apparent increase in the stability seems to be due to either antibacterial activity of oxidized CTC or of oxidized oil per se. Data herein reported made it clear that a disagreement among the works above-cited on the stability of CTC in tissues was resulted from a difference among tissues employed by the above cited authors in their ferric iron content and the rate of oxidation of oil in tissues.

FACTORS CAUSING ERROR IN BIOASSAY OF CHLORTETRACYCLINE IN TISSUES

In the course of study on chlortetracycline (CTC)-residue in the antibiotic-treated food, a possibility was presumed that CTC-residue of salt-dried fish might give a lower value probably due to the inactivation of CTC by oxidized oil, or might give a higher value due to the growth inhibition of the assay organism by the presence of sodium chloride in a sample extract. Furthermore, experiences in our laboratory revealed that the inhibitory zone size became smaller in hot season. Therefore, the present study was undertaken to modify the procedure so that the method can deal with such sample possessing salt and fatty acid peroxide and also can give a higher sensitivity even at high room temperature. It was shown that a factor responsible for the inactivation of CTC probably peroxidic free radical occurred markedly when the concentration of acetone was increased. It was observed that when acetone-citrate extractant was employed, salt effect occurred in a sodium chloride concentration range above 2%. It was found that the error due to the presence of salt and the inactivating factor can be removed by employing an aqueous M/50 citrate buffer (pH 5.2) as the extractant of CTC from sample. Assay sensitivity at higher room temperature was increased when the assay plate was refrigerated 30 minutes before and after placing a sample extract into the cylinder.

A PRACTICAL ASSAY METHOD FOR DETERMINATION OF TETRACYCLINE AND OXYTETRACYCLINE IN TISSUES

TOMIYAMA et al3) reported a practical assay method appropriate for the determination of minute amount of chlortetracycline (CTC) in tissues. The present study deals with the application of their method to the determination of tetracycline (TC) and oxytetracycline (OTC) in tissues. It was found that the method could be applied for this purpose by only modifying the standard antibiotics solutions. The average recoveries of TC or OTC which was included in tissues were found 88% from muscle and 96% from skin. The minimum inhibitory concentration of TC or OTC was 0.006 mcg per cc., i.e., a detectable amount of OTC in tissues being 0.03 mcg per g. of tissue when one part of a sample tissue is extracted with four parts nation could be omitted by employing the linear regression line just as in the case of CTC. The optimum condition for the sporulation of test organism, B. cereus # 213, has also been studied, since difficulty was frequently met in obtaining a high yield of spore of the test organism while none was experienced in case of B. cereus # 5. Several trials revealed that both a suitable cell concentration of the inoculum and a moderately thin layer of the basal medium are required for efficient sporulation of the organism.

Studies on Utilization of Trimmings Wasted in Manufacturing “Kamaboko”, a Cooked Fish Cake-IV

In all the experiments on egg production which have hitherto been carried out1-3), use was made of rather small number of hens and of the battery house. The present study has been carried out on one-year old hen without using the battery house and under conditions as practical as possible. The results obtained can be summarized as follows: 1. The supplementation of the solubilized trimmings at a 5% dry basis level gave more egg production as compared with that of fish meal at a 10 per cent level. 2. The partial replacement of the fresh trimmings with the solubilized trimmings yielded more or less a favorable effect on egg production. 3. The supplementation of the solubilized trimmings at a 2.5 per cent dry basis level gave egg production similar to the control group, while a little increase was observed from July to September.

Studies on Utilization of Trimmings Wasted in Manufacturing Cooked Fish Paste-III

Chicks fed a diet supplemented with the solubilized trimmings at a 2 or 3 per cent dry basis level for 8 to 32 weeks showed a significant growth response, (Table 1 and 2). The difference in body weight between the chicks fed the solubilized trimmings and the control chicks fed only all-vegetable protein ration was significant at a 5% level (Table 1). It is to be noted that earlier start of egg production has been found in the experimental group (Table 2). It has been shown that chicks which were raised on the ground without using battery-house gave an increase of 14 per cent in the growth rate after 9 weeks by feeding an all-vegetable protein ration with the solubilized trimmings at a 3 per cent level (Table 3).