A Study on the Preservation of Fish-cake-III

Various experiments have been conducted to prolong storage time of fish-cake by the helpof chemical preservatives, such as nitrofurazone, dehydro-acetic acid and hydrogen peroxide etc, however, there were found too much difficulties left unsolved to apply them directly for daily practice of the industry.<br> E. N_OGUCHI and S. H_IGASA reported certain packaging materials are useful for the purpose of fish-cake preservation and stated that non-sugard fish-cake stuffed in polyethylene or vinyl chloride casing showed neither bacterial slime on their surface nor putrefactive odor after 7 day's storage.<br> In the present report, also the results of several experiments concerning the preserving effect of plastic casing for fish-cakes are described.<br> As will be seen in Table 1, very little increase in the amounts of volatile basic nitrogen, an index of spoilage, were found for non-sugared fish-cake which had been stuffed in polyethylene casing during 5 day's storage at 30°C.<br> Also similar results, as shown in Table 2, has been obtained for non-sugared fish-cake which was stored under anaerobic condition by eliminating oxygen from the medium with al kaline pyrogallol solution.<br> On the basis of above findings, it will be inferred that preservative effect due to plastic casing for fish-cake is chiefly dependent upon the extent of airtightness which can be attained when fish-cake is stuffed in these casing. But addition of some fermentable sugars was found to be as inadequate for the preservation of fish-cake by plastic casing, because such glucose and sucrose are known as very favorable carbohydrate source for accelerating the growth of some kinds of micro-organisms under anaerobic condition.<br> Therefore, in the case of sugared fish-cake, sole use of plastic casing or keeping in oxygenfree medium is not enough to expect complete preservation of the products.<br> Much production of lactic acid was observed for both samples of sugar added fish-cakes, which were preserved in polyethylene casings or under anaerobic condition. It is not so easy to avoid putrefaction of these sugared fish-cake products only by the aid of plastic casings.<br> E. F. G_ALE has already proved that occurrence of amino acid decarboxylation is likely assisted by the growth of micro-organisms under acidic enviroment. Much amounts of lactic acid produced and decrease is pH value of the product could be pointed out as the features of progress in putrefaction of sugar containing fish-cake products.<br> Meanwhile, in the course of spoilage of sugared fish-cake no appreciable increase in the amount of histamine was detected by colorimetry of diazo reaction, after isolating histamine with cotton acid succinate.<br> Moreover, in the sample of fish-cake added l00mg per cent of histidine, histamine could not be produced in measurable amount as shown in Table 7.