The microflora of semi-preserved fish products II. The effect of the quality of raw materials,added materials,and storage conditions

This paper is concerned with titbits, i.e. canned fish products that have not been subjected to heat, but which have certain keeping qualities thanks to their high salt content, low pH, and the addition of preservatives.The effects of such factors as the raw material used, the composition of the pickle added to the titbits before they are canned, and physical procedures, e.g. freezing and thawing, on the keeping qualities of the titbits have been investigated.The keeping quality varied substantially with the amount of sugar added to the pickle, a high sugar content markedly prolonging and a low sugar content shortening the maximum tolerable duration of storage of the products.Sodium benzoate proved to have a good effect as a preservative, while nisin had no demonstrable antibiotic effect at all.Freezing of canned titbits before storage at 20 C produced some improvement in keeping qualities and seemed to damage some types of bacteria present.In fermented specimens of titbits the microflora was dominated by cocci and lactobacilli. However, the total amount of bacteria initially present in the cans is not directly correlated to the keeping qualities of the product.