Doctoral Dissertations

Date of Award

6-1985

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Food Science and Technology

Major Professor

F. A. Draughon

Committee Members

H. O. Jaynes, C. C. Melton, F. M. Applehans

Abstract

The objectives of this study were to develop a soy extended semidry Thuringer sausage and study its sensory characters to study its potential as a substrate for toxin production if contaminated by Aspergillus parasiticus or Penicillium citrinin. Thuringer sausage was formulated by adding 0, 5, 10, 15 and 20% hydrated textured soy protein. The cooked and smoked products were subjected to sensory evaluation on an eight point hedonic scale. The addition of soy did not affect the pH of the final product. A linear relationship between the sensory score and soy level was observed. It was concluded that Thuringer sausage can be formulated by adding up to 12% hydrated soy protein without causing any adverse affect on the product. A reduction in premix time was achieved. Slices of nonextended (NE), soy extended (SE) and commercial (CM) sausages were infected separately with 106 spores of A. parasiticus and P. citrinum and maintained at equilibrium relative humidities of 80% and 93% at 21°C and at 31°C. Samples were analyzed for aflatoxin B1, aflatoxin G1 and citrinin at 7, 14, 21, and 28 day intervals. A. parasiticus grew well on all three sausage samples. Toxin levels were detected as early as 7 days and remained detectable until 28 days. The effect of relative humidity (RH) and temperature on toxin production varied with each sample, but the incubation time did not show any effect. Overall, higher levels of aflatoxin B1 were detected at 80% RH than at 93% RH and at 21 °C than at 31 °C. Higher levels of B1 were detected in CM samples than in NE and SE samples. Aflatoxin G1 production followed the same patterns as those of aflatoxin B1 in NE and SE samples, but in CM samples more G1 was pro-duced at 31 °C than at 21 °C. More G1 was produced in CM and SE samples than in NE samples. Citrinin production was sporadically detected in all three samples. The CM sausage samples appeared to be the best and SE to the worst substrates for citrinin production. Citrinin was detected more fre-quently at 93% RH than at 80%. All three sausage samples were equally hazardous if contaminated by toxigenic fungi, and addition of soy neither increased or decreased toxin production potential by toxi-genic fungi.

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