Degree Type

Dissertation

Date of Award

1987

Degree Name

Doctor of Philosophy

Department

Food Technology

Abstract

Tetrasodium pyrophosphate and sodium acid pyrophosphate were examined first separately or in combinations at a level of 0.4% of meat weight. Sodium acid pyrophosphate inhibited streptococci during storage of the cooked, vacuum-packaged sausage for 48 hours at 20-22(DEGREES)C, whereas tetrasodium pyrophosphate did not. Neither phosphate had a significant antimicrobial effect during 21 days of refrigerated storage at 5(DEGREES)C;Combinations of sodium acid pyrophosphate and trisodium pyrophosphate, a pH-neutral pyrophosphate, were used in a second study in cooked pork sausage also at a level of 0.4% of meat weight. Sausages without phosphate had lower bacterial numbers after 1 day at 7(DEGREES)C than those containing phosphates, but phosphate-treated sausages had significantly lower mesophilic bacterial counts after 21 days of refrigerated storage at 7(DEGREES)C, and also significantly lower mesophilic and facultative anaerobic bacterial numbers after 24 and 48 hours of elevated temperature storage (20-22(DEGREES)C). There was no difference in total microbial numbers between any of the phosphate treatments. However, sodium acid pyrophosphate inhibited streptococci to a greater extent than did trisodium pyrophosphate;The third part of the work was a study of the microbiological effects of 3 levels of commercial phosphate blends and of trisodium pyrophosphate in a cooked, vacuum-packaged meat system. Control treatments contained no added phosphate. There were no differences in antimicrobial activity between the various phosphates studied during low temperature (5(DEGREES)C, 7 days) or high temperature storage (20-22(DEGREES)C, 48 hrs.). However, there were highly significant differences between the levels of phosphate added, both during refrigerated storage and temperature abuse storage. During refrigerated storage, control treatments had significantly higher mesophilic and facultative anaerobic bacterial counts than the two intermediate phosphate levels (0.3-0.48%), and the highest level of phosphate had significantly lower mesophilic and facultative anaerobic bacterial counts than the two intermediate levels. The same pattern of inhibition was observed during storage of the sausage at 20-22(DEGREES)C.

DOI

https://doi.org/10.31274/rtd-180813-8626

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

John Allen Marcy

Language

en

Proquest ID

AAI8716792

File Format

application/pdf

File Size

133 pages

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