Prevention of Foodborne Pathogens and Industrially Relevant Spoilage Microorganisms: Synergism of an Emerging Technology with Traditional Preservation Methods
The current project investigated the effect of mild heat and elevated hydrostatic pressure of 380 MPa, and nisin on the inactivation of L. monocytogenes, L. innocua, and spoilage microorganisms. The pathogen mixture was exposed to three different treatments: application of pressure in the presence of mild heat, a combination of mild heat with nisin, and the last treatment included the combination of mild heat, pressure, and nisin. The treatments were carried out for 0, 3, and 5 min. The project also studied the effect of two different temperatures (4.4 °C and 60.0 °C) and their combination on two different pressure parameters (380 and 650 MPa) along with malic acid. The results showed that nisin augmented the decontamination efficacy of elevated hydrostatic pressure at a treatment interval of 3 min when used in synergism with hydrostatic pressure. The study also showed that high temperature of 60.0 °C and high hydrostatic pressure along with malic acid have better decontamination effect against Shiga toxinproducing E. coli O157:H7. The current study additionally compared biofilm formation of six-strain mixtures of Shiga toxin-producing E. coli O157:H7 (STEC) and non-O157 Shiga toxin-producing E. coli (nSTEC). The experiment compared biofilm formation of two sets where one set included the comparison of wild-type STEC and nSTEC and the other included comparison of both serogroups for rifampicin-resistant strains. The log reductions for treatment with sodium hypochlorite treatments for STEC and nSTEC were 2.9 and 3.5, respectively, which accounted for greater than 99% inactivation of bacterial biofilms. On day 21, the treatment with quaternary ammonium compounds resulted in a 2.9 log reduction for nSTEC. These results showed the industrial importance of bacterial biofilm and exhibited resistance to commonly available commercial treatments validated in the past against planktonic cells. These results could be incorporated as part of food safety management systems, such as those articulated in Hazard Analysis and Critical Control Point and Food Safety Modernization Act regulations to ensure the microbiological safety of the food products and to improve public health.
"Prevention of Foodborne Pathogens and Industrially Relevant Spoilage Microorganisms: Synergism of an Emerging Technology with Traditional Preservation Methods"
ETD Collection for Tennessee State University.