Effect of Air Temperature and Velocity on Listeria monocytogenes Inactivation During Drying of Apple Slices

• Published in: Journal of food protection 2024-04, Vol.87 (4), p.100253, Article 100253
• Main Authors: Randriamiarintsoa, Narindra, Ryser, Elliot T., Marks, Bradley P.
• Format: Article
• Language: English
• Subjects: Air flow; Colony Count, Microbial; Dehydration; Food Handling - methods; Food Microbiology; Fruit; Fruit - microbiology; Listeria monocytogenes; Malus - microbiology; Moisture; Pathogen; Temperature; Thermal inactivation
• ISSN: 0362-028X; 1944-9097; 1944-9097
• DOI: 10.1016/j.jfp.2024.100253

•Listeria survival was greater at 60 than 80 °C, regardless of air velocity.•Inactivation of Listeria was greater at higher air velocity.•Final moisture content did not correlate with reductions of Listeria.•A 5-log reduction of Listeria was observed when drying apples at 80 °C. A wide range of drying parameters and methods are used by industry to produce dried apples. To ensure end-product safety and regulatory compliance, it is essential to evaluate the effectiveness of such industrial practices on microbial inactivation. Therefore, the objective of this study was to evaluate the effects of drying air temperature and velocity on Listeria monocytogenes inactivation during drying of apple slices. Apples (cv. Gala) were cored, sliced as rings (∼6 mm thick), and surface-inoculated with broth-grown culture of an 8-strain cocktail of L. monocytogenes to achieve an inoculation level of 8.6 ± 0.3 log CFU/g. Apple rings were dried in batches using dry air in a pilot-scale impingement oven at 60 or 80 °C air temperature and 0.7 or 2.1 m/s air velocity, and sampled every 30 min for bacterial enumeration, water activity (aw), and moisture content analysis. L. monocytogenes reduction increased (P