Inactivation of Salmonella enterica in 3D Printed Ready-to-eat Pudding

  • Author / Creator
    Barsukova, Yuliya
  • Three-dimensional (3D) food printing is a rapidly developing technology that transforms digital data as input to create a 3D edible physical product as output. It has the potential to change the food industry by offering highly customizable nutritional profiles and designs, while reducing food waste and the cost of manufacturing. The most widespread 3D printing method is extrusion-based, and it requires ingredients fluid enough to be extruded and viscous enough to hold their shape after deposition. As a result, many of these ingredients have high moisture content and some are meant to be consumed immediately after preparation as ready-to-eat products. Microbial food safety is an important consideration for these high moisture ready-to-eat 3D printed food products. Despite the technological advancements in 3D food printing, microbial safety aspect of 3D printed foods has not been fully investigated.
    In this study, inactivation rate of Salmonella enterica serovar Typhimurium in a printed 3D square made of pudding was assessed. Before and during printing the pudding was heated at selected time-temperature combinations inside the 3D food printer. The temperature profiles evaluated were A (56.9°C), B (60.3°C), C (63.3°C) and D (66.7°C) and time increments were 10, 20, 30 and 40 min. Inactivation of Salmonella increased with temperature and heating time, with the highest reduction of >7 log CFU/g after 40 min at temperature profiles C and D. Inactivation of Salmonella after 10 min treatment at all the temperatures was not significantly different, and 40 min treatment at profile B was not significantly different from profiles C and D at 30 min. To preserve quality and nutritional parameters of 3D printed foods, lower temperature-longer time treatment may be preferred.
    The second part of this study focused on the simulation of the heating of pudding in the plastic extrusion syringe inside the 3D printer by finite element modeling using axisymmetric 2D model. The experimental time-temperature relationships at the selected locations of the syringe including at the center and the gap between the syringe and 3D printer’s stainless-steel barrel during the heating of pudding were compared with simulation results. Overall, the predicted temperature changes were in good agreement with the experimental values. In addition, there was no considerable difference in the heating profiles of syringe quarter points, however, the contour plots showed heat loss due to convection at the top of the syringe. These results indicate the potential of finite element analysis to be used in conjunction with 3DFP as a useful tool for analyzing heat transfer and distribution in a closed system.

  • Subjects / Keywords
  • Graduation date
    Spring 2024
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.