A comparative study of infrared and microwave heating for microbial decontamination of paprika powder

Abstract

There is currently a need in developing new decontamination technologies for spices due to limitations of existing technologies, mainly regarding their effects on spices’ sensory quality. In the search of new decontamination solutions, it is of interest to compare different technologies, to provide the industry with knowledge for taking decisions concerning appropriate decontamination technologies for spices. The present study compares infrared (IR) and microwave decontamination of naturally contaminated paprika powder after adjustment of water activity to 0.88. IR respectively microwave heating was applied to quickly heat up paprika powder to 98°C, after which the paprika sample was transferred to a conventional oven set at 98°C to keep the temperature constant during a holding time up to 20 min. In the present experimental set-up microwave treatment at 98°C for 20 min resulted in a reduction of 4.8 log units of the total number of mesophilic bacteria, while the IR treatment showed a 1 log unit lower reduction for the corresponding temperature and treatment time. Microwave and IR heating created different temperature profiles and moisture distribution within the paprika sample during the heating up part of the process, which is likely to have influenced the decontamination efficiency. The results of this study are used to discuss the difficulties in comparing two thermal technologies on equal conditions due to differences in their heating mechanisms.

Decontamination of Bacillus cereus in cardamom (Elettaria cardamomum) seeds by infrared radiation and modeling of microbial inactivation through experimental models

“…Different technologies including electron beam (Nieto‐Sandoval, Almela, Fernandez‐Lopez, & Munoz, ), X‐ray (Van Calenberg et al, ), ultraviolet (Erdoğdu & Ekiz, ), microwave (Eliasson, Isaksson, Lövenklev, & Ahrné, ), and infrared (IR) radiations (Erdoğdu & Ekiz, ) have been used for microbial decontamination of spices. Infrared is a section of the electromagnetic spectrum with wavelengths (0.76 μm and 1 mm) between those of ultraviolet (UV) and microwave radiation (Krishnamurthy, Khurana, Jun, Irudayaraj, & Demirci, ).…”

“…Infrared is a section of the electromagnetic spectrum with wavelengths (0.76 μm and 1 mm) between those of ultraviolet (UV) and microwave radiation (Krishnamurthy, Khurana, Jun, Irudayaraj, & Demirci, ). Due to the low penetration depth of IR radiation (0.31 to 4.76 mm), this method is used as a surface treatment (Eliasson et al, ).…”

Efecto de la aplicación de vapor saturado como Sistema de Esterilización Orgánica (OSS) en el ají mirasol (Capsicum baccatum var. pendulum) y en el ají panca (Capsicum chinense Jacq.)

“…Se reportaron valores del contenido de levaduras ≤10 UFC/g, E. Coli <3 NMP/g, ausencia en Salmonella y coliformes totales <3 NMP/g para ambas variedades de ajíes. Se determinó que al aplicar vapor saturado al ají mirasol y al ají panca las muestras cumplen con los requisitos de aerobios mesófilos, coliformes totales y Salmonella estipulados en la Norma 591-2008(Norma Sanitaria, 2008, lo cual ofrece ventajas comparativas frente a otros métodos como la radiación ultravioleta, radiación ionizante, microondas y radiofrecuencia aplicadas a alimentos deshidratados (Gabriel et al, 2020ª, 2020bMolnár et al, 2018); por esta razón, en Europa es el método más aceptado (Eliasson et al, 2015). Esta tecnología es una gran alternativa para la descontaminación microbiana.…”

Quality Management in Spice Paprika Production: From Cultivation to End Product

“…Cultivation is a common source of pesticide residues, and unfavourable harvest conditions may give rise to mycotoxins by pathogenic fungi. Spice paprika, as other spices, often becomes naturally contaminated with various bacteria (e.g., Salmonella spp., Bacillus cereus, Escherichia coli [5]) generating microbial hazard [6]. Storage and post-ripening prior to processing is attributed with microbial contamination and possible increases in mycotoxin content, and may significantly affect quality features.…”