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Maximizing quality and controlling pathogens in protein rich foods through thermal and non-thermal technologies
Outbreaks of food borne pathogens such as Salmonella and E. coli O157: H7 have been raised public concerns for several decades. Many researchers are committed to provide more and more useful information in order to help industries and companies to ensure food products are safe and healthy with higher qualities. In the current work, different pathogenic microorganisms (Salmonella and E. coli) associated with two types of protein rich food products (egg white powder and beef) were studied regarding safety, quality or sensory characteristics through thermal and non-thermal technologies: (i) The thermal destruction of Salmonella spp. in egg white powder was determined (ii) The effect of high pressure processing (HPP) on the destruction of E. coli O157:H7 and quality changes in beef steaks intended for sous vide (SV) cooking was studied; (iii) Texture, color and sensory evaluation of sous vide cooked beef steaks using HPP as a hurdle were determined. Destruction parameters (D- and Z-values) were obtained by three thermal destruction methods in high gel and standard egg white power, the D-values of high gel EWP resulted in significantly (P < 0.05) lower from standard EWP, which means pH plays an important role in destruction. These results and findings can be potentially applied for the use of Radio Frequency (RF) assisted heating system in future studies. High pressure processing (HPP) can achieve E. coli O157:H7 reductions in excess of the 5-log definition of pasteurization using 450 MPa for 15 minutes or 600 MPa for 10 and 15 minutes. HPP at 450 or 600 MPa did not significantly change the properties of most partially roasted beef steaks in term of pH, water activity, moisture content, expressible moisture, but caused lipid oxidation and decreased the tenderness of the partially cooked beef steaks. For consumers, SV control and SV post-HPP were ranked differently (P < 0.05). SV control were rated higher (P < 0.05) for tenderness juiciness and overall liking than SV post-HPP, but not differently (P > 0.05) for taste and aftertaste liking from SV 450 MPa. These results indicate HPP can have some negative impact on quality and sensory characteristics of beef steaks, but still may be potentially accepted by consumers with optimized pressure and time.
Sun, Shengqian, "Maximizing quality and controlling pathogens in protein rich foods through thermal and non-thermal technologies" (2016). ETD collection for University of Nebraska - Lincoln. AAI10247762.