Spices: decontamination through radio frequency heating

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In this work effectiveness of radiofrequency (RF) heating has been tested to disable Salmonella Typhimurium and Escherichia coli O157: H7 in samples of pepper and chili pepper. In particular, the tests were carried out using 27.12 MHz system consisting of two plate electrodes between which the spices are located. The samples were inoculated (at 6 log CFU/g concentration) with both microorganisms and processed for 40-50 sec. After treatment, the spices also have been analyzed in terms of changes in colorimetric characteristics. Results demonstrate that RF heating causes significant concentration reductions of both microorganisms (in the range between 3 and 5 log CFU/g) both in pepper, and chili pepper. The authors point out that the effectiveness of the treatment is mainly based on thermal effects as the denaturation of enzymes, proteins, nucleic acids and destruction of cell walls. Finally, the survey shows that RF heating doesn’t have significant effects on the two spices’ color.

Bibliographic references

S.-Y. Kim et al., International Journal of Food Microbiology, 153, 2012, 171-175