Growth patterns of Pseudomonas aeruginosa in milk fortified with chitosan and selenium nanoparticles during refrigerated storage

Abstract

Abstract Pseudomonas spp are considered the most common milk-associated psychotropic bacteria, leading to milk deterioration during storage so, our study aimed to study the growth behavior of Pseudomonas aeruginosa in milk after employing chitosan nanoparticles (CsNP 50, 25 and15 mg/100ml) and selenium nanoparticles (SeNP 0.5, 0.3 and 0.1mg/100ml) as a trial to control the bacterial growth in milk during five days of cooling storage. Our study relies on using ion gelation method and green synthesis for conversion chitosan and selenium to nanosized particles, respectively, we subsequently confirmed their size and shape using SEM and TEM. Depending on using Pseudomonas selective agar medium supplemented by glycerol for monitoring the bacterial growth along the cooling storage. Our findings reported that, both synthesized nanoparticles exhibit antibacterial activity in a dose dependent manner. Moreover, the uniform aggregated with average size 60 ± 5 nm CsNP50 could inhibit the P. aeruginosa survival growth to mean average 2.62 ± 1.18 log10cfu/ml in the fifth day of milk cooling storage, also it was noted that the hexagonal particles with average size 20 ± 5nm SeNP0.5 could inhibit 2.49 ± 11 log10cfu/ml in comparison to, the control P. aeruginosa milk group exhibited growth survival 7.24 ± 2.57 log10cfu/ml under the same conditions. As conclusion, in order to improve milk safety, we suggest employing chitosan and selenium nanoparticles.