Optimization of Determined Pathogenes Deactivation and Investigating the Quality of Bottled Milk under Cold-Plasma Treatment

Abstract

In this study, a surface discharge plasma system including a cylindrical system was used for the treatment of milk in bottle. Electric discharge was performed to the electrode with the studied frequency and voltage. To optimization the process, the Design Expert software and optimal factorial design were used. The destruction time of Bacillus cereus, Bacillus Coagulans, Bacillus stearothermophilus, and Clostridium botulinum microorganisms, nutritional compounds or the occurrence of chemical reactions, and the time of inactivation of catalase, alkaline phosphatase, lipase, peroxidase, and protease enzymes, bovine serum albumin, immunoglobulins, alpha lactalbumin, beta lactalbumin, lysine and thiamine were also considered as answers in the Design Expert. The simulation was performed by COMSOL a3.5 software for a two-dimensional geometry. Among the four studied bacteria, Bacillus stearothermophilus had the highest resistance to cold plasma and other bacteria showed low resistance. In Cold plasma treatment wich investigated in this study, changes in initial temperature had a greater effect on the amount of production of active species than changes in voltage. Under the influence of non-thermal plasma treatment, the denaturation time of the studied proteins and amino acids has a significant difference at the 5% level. In the meantime, the inactivation time of lysine amino acid was shorter than other cases, and β-lactalbumin protein had the longest destruction time. Cold plasma technology can be used as a new antimicrobial intervention to inactivate pathogens and improve the safety of dairy products.

Keywords

• bottled milk
• cold plasma
• comsol
• response surface methodology
• sterilization