Effect of citric acid, citrate and slight a(w) decreases on the bacteriological stability of Hague liver sausage.

Combinations of citric acid and citrate, with several carbohydrates and KCl, were tested in a canned Hague liver sausage model for their antimicrobial properties. pH values for the test products ranged from 5·38 to 6·48; a(w) values varied from 0·960 to 0·977. Before pasteurization, the sausage doughs were contaminated with mixtures of bacterial spores. Since the bacteriological stability sometimes appeared to be considerably improved, heated packages were challenged by incubation at 20° and 30°C; some of them for up to 2 years. Incubated packages from the standard formulation spoiled at 30°C within 3 days. Starting from this point, products with a variable, but increased, bacteriological stability were obtained. For the best stabilized batches, first symptoms of spoilage were observed after periods of incubation at 30°C, ranging from 49 to 150 days. Combinations of pH and a(w) values which can be relied upon to yield stable products consistently, cannot be derived from the accumulated data. Citric acid appeared a far more effective stabilizer than its salt. If we regard the undissociated citric acid concentration for these products (a(w) 0·960-0·972) as a significant parameter, values above approximately 13 μmkg(-1), yielded products with remarkable bacteriological stability.