R. Perren, T. Lohmüller, 2012, PASTEURIZATION OR STERILIZATION OF SPICES – FOOD SAFETY AND QUALITY CONSIDERATIONS, Presentation at the IAFP 2012 annual meeting , July 22-25, 2012, Providence RI.

Introduction: Spices are highly contaminated with pathogenic microorganisms and represent a major hazard for food production and consumption. As not only vegetative microorganisms are present in spices, decontamination normally aims at a reduction of total plate count, which is achieved only if elevated sterilization conditions are applied.

Purpose: It was the purpose of this work to pasteurize and sterilize spices in a steam condensation process  and to discuss the sanitation concept optimizing food safety and maximizing quality retention.

Methods: Spices were inoculated with Enterococcus faecium NRRL B 2354, a heat resistant surrogate for Salmonella, and with Geobacillus stearothermophilus, a heat resistant surrogate for spore forming microorganisms. The inoculated products were steam-treated in a controlled condensation process CCP at varying conditions. The inactivation of microorganisms and product quality alterations were assessed.

Results: Product properties with respect to color and volatile oil concentration changed slightly depending on process conditions (Time-temperature-moisture-profile), whereas temperature and moisture conditions exhibited a predominant influence. At pasteurization conditions lower than 100°C, the change in product quality were considerably lower than a sterilization condition higher than 100°C. Enterococcus faecium was inactivated by more than 5 log units at comparably mild conditions (81-91°C for 5 min). At such conditions spore formers are hardly harmed but activated. Depending on their heat resistance properties, spores formers such as Geobacillus stearothermophilus were completely inactivated below detection level at elevated process conditions starting from 100°C only.

Significance: These results show that spices may be pasteurized in a validated process at mild and quality preserving conditions in order to reduce the risk for a salmonella contamination. Although proper pasteurization virtually eliminates the pathogenic risk, total plate counts may still be elevated depending on the initial spore contamination. Hence, successful pasteurization may not be monitored by total plate count analysis. The requirements to validate the pasteurization process on an industrial scale are discussed.