No abstract

Lactic fermented fish products are common in South East Asia. The composition and quality of the products vary considerably since they are usually produced on a small scale and the fermentation of the fish-salt-carbohydrate mixtures depends on the natural microflora. A minced fish-salt-glucose system was used to evaluate the factors that favour a rapid lactic fermentation. Studies with Lactobacillus plantarum and Pediococcus pentosaceus indicated that fermentation rates increase in the range 0-5% w/w of glucose or sucrose, whereas increasing the salt concentration from 0 to 6% slows the rate of pH decrease. Conditions of 1% salt and 4% glucose were used for subsequent studies. The nature of the gas atmosphere during incubation had little effect on fermentation rate and chemical modification of the initial substrate pH with lactic, acetic or citric acid did not assist the lactic fermentation. Incubation temperatures of 15, 24, 30 and 37°C were evaluated: the lactic acid bacterial count rarely exceeded the total spoiler count by more than ten-fold during the first 2 days (although it subsequently increased). Consequently the objective of reducing the pH to below 4.5 within the first 2 days was difficult to achieve. The use of cooked fish minces gave only slight changes in the fermentation rate.

Gari, a fermented cassava product, is widely consumed in many West African countries. The present study was undertaken to investigate the detoxification of cassava during the preparation of gari. The most important processing stages, with regard to elimination of cyanide, were the initial grating of the cassava and the final roasting of the product. The breakdown of linamarin was dependent primarily on the presence of endogenous linamarase and the lactic acid bacteria present during the fermentation were not directly involved in its hydrolysis.

The range of traditional lactic‐acid‐fermented foods in tropical countries is briefly reviewed. Recent studies on the lactic acid fermentation of fish and cassava products are described. Lactic‐acid‐fermented fish products may offer considerable scope for the development of new food products and for the use of under‐utilised fish species. Lactic‐acid‐fermented fish products are common in parts of Asia; methods to improve the product and shelf‐life quality, to reduce microbial risks and to accelerate the process are described. This work is based on fish/salt/carbohydrate model systems. The nutritional aspects of cassava fermentation are discussed with respect to factors involved in determining residual cyanide levels; the possible anti‐nutritional rôle of condensed tannins is mentioned. The increasing consumption of meat products in tropical countries emphasises the need for a preservation method that does not depend on refrigeration. The possible production of sausage ingredients preserved by lactic acid fermentation, and the associated research needs are described.