Modeling inactivation kinetics for Enterococcus faecium on the surface of peanuts during convective dry roasting

Kaitlyn E. Casulli, Matthew J. Igo, Donald W. Schaffner, Kirk D. Dolan

Research output: Contribution to journalArticlepeer-review

Abstract

Dry roasting can reduce Salmonella contamination on peanuts. While previous studies evaluated impact of product temperature, process humidity, product moisture, and/or product water activity on Salmonella lethality, no published study has tested multiple primary and secondary models on data collected in a real-world processing environment. We tested multiple primary and secondary models to quantify Salmonella surrogate, Enterococcus faecium, inactivation on peanuts. Shelled runner-type peanuts inoculated with E. faecium were treated at various air temperatures (121, 149, and 177 °C) and air velocities (1.0 and 1.3 m/s) for treatment times from 1 to 63 min. Peanut surface temperature was measured during treatment. Water activity and moisture content were measured, and E. faecium were enumerated after treatment. Microbial inactivation was modeled as a function of time, product temperature, and product moisture. Parameters (Dref, zT, zaw, zMC, and/or n) were compared between model fits. The log-linear primary model combined with either the modified Bigelow-type secondary model accounting for aw or moisture content showed improved fit over the log-linear primary model combined with the traditional Bigelow-type secondary model. The Weibull primary model combined with the traditional Bigelow-type secondary model had the best fit. All parameter relative errors were less than 15%, and RMSE values ranged from 0.379 to 0.674 log CFU/g. Incorporating either aw or moisture content in the inactivation models did not make a practical difference within the range of conditions and model forms evaluated, and air velocity did not have a significant impact on inactivation. The models developed can aid processors in developing and validating pathogen reduction during peanut roasting.

Original languageEnglish (US)
Article number110766
JournalFood Research International
Volume150
DOIs
StatePublished - Dec 2021
Externally publishedYes

ASJC Scopus subject areas

  • Food Science

Keywords

  • Dry roasting
  • Enterococcus faecium
  • Inactivation
  • Modeling
  • Parameter estimation
  • Peanut
  • Salmonella

Fingerprint

Dive into the research topics of 'Modeling inactivation kinetics for Enterococcus faecium on the surface of peanuts during convective dry roasting'. Together they form a unique fingerprint.

Cite this