Modeling of Listeria monocytogenes inactivation by combined high-pressure and mild-temperature treatments in model soup

作者：Ates Mehmet Baris^*; Rode Tone Mari; Skipnes Dagbjorn; Lekang Odd Ivar

来源：European Food Research and Technology, 2016, 242(2): 279-287.

DOI：10.1007/s00217-015-2539-2

• HPP
• Mild heat
• Listeria monocytogenes
• Inactivation model
• Injury
• Recovery

High-pressure processing (HPP) in combination with mild heat is known to have a synergistic effect on bacterial inactivation in broth, milk and meat. This synergistic effect has, however, not been documented for a ready-to-eat (RTE) soup. In this study, Listeria monocytogenes inactivation in a model RTE soup under combined high-pressure and mild-temperature (P/T) treatments was modeled according to a central composite design. The model was significant (P < 0.0001) with a satisfactory predictability (R (adj) (2) = 0.95). Effects of P/T on L. monocytogenes inactivation were assessed by solving the deduced quadratic equation and analyzing its contour plot. More than 6-log inactivation of Listeria was possible at combined P/T ranges of 525 MPa/40 A degrees C to 600 MPa/25 A degrees C within 5 min. This was in accordance with FDA and EC guidance on refrigerated RTE foods that a treatment intensity equivalent to 6-log reduction of L. monocytogenes would be required as a listericidal control measure. Moreover, 600 MPa treatments at a parts per thousand yen45 A degrees C for 5 min resulted in no L. monocytogenes recovery in the model soup during 3 weeks at 4 and 8 A degrees C when the inoculum size was 10(3) or 10(5) CFU/ml. Results clearly indicated that use of mild temperatures in combination with HPP can induce a more complete inactivation, hence reducing the microbial recovery in foods after HPP. Experimental results and the fitted model in this study may be utilized as a comparison to other inactivation models and for determining test conditions for process safety assessments on similar refrigerated products in food industry.

• 出版日期2016-2