Effect of Carum copticum nano-essence against Saprolegnia and Fusarium, and the Use of Multiplex PCR Assay for the Detection of These Organisms in Rainbow trout Oncorhynchus mykiss

This study aimed to investigate the fungal species isolation and confirmation by the Multiplex PCR method in aquatic fish. Evaluation of the inhibitory effect of nano-essential oils of Carum copticum on isolated fungal species was also conducted in this study. The PCR results showed that 3 out of 5 samples were diagnosed with Fusarium solani, and two of them were positive for Saprolegnia. Moreover, in 0.1% of the females' nanoparticles, one peak appeared that showed a particle with an average diameter of 360 nm, and two nanoparticles showed a peak with a mean diameter of 242 nm. The results of minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) showed that 0.01% nano essential oil had 0.08 and 0.07 mg/ml MIC values against Fusarium solani and Saprolegnia, respectively. Gram/ml was on the growth of Fusarium solani species. The essential oils of female plants had an MIC of 0.07 in 0.1% essential oil and 0.03 mg/ml in 0.01% essential oil in Saprolegnia. Furthermore, in the case of 0.1% nano essential oil, the results showed the MIC values of 0.04 and 0.03 mg/ml against Fusarium solani and Saprolegnia, respectively. The MFC values of 0.1% nano essential oil were 0.1 and 0.07 mg/ml against Fusarium solani and Saprolegnia, respectively. It was not found on Fusarium and Saprolegnia. Overall, the results of this study using PCR for direct detection showed that 70% and 50% of the samples were Fusarium solani and Saprolegnia positive, respectively; therefore, the PCR was an efficient method for the detection of fungi. According to the results of nano-essential oil (0.1%) of females, this nano-essence had a strong inhibitory effect on Fusarium solani and Saprolegnia.

Effect of Four Chicken Carcass Transportation Methods at Selected Room Temperatures on the Bacterial Load of Staphylococcus aureus, Salmonella species, and Escherichia coli

Pathogenic bacteria are responsible for a significant number of food poisonings in humans through infected poultries. The main objective of this study was to assess the effect of transportation of chicken carcasses at 18-24, 4-5, and 10-14 oC on the bacterial loads of Staphylococcus aureus, Salmonella species, and Escherichia coli. This study was conducted on 180 fresh chicken carcasses (1197.0±19.88 g) randomly collected from a commercial poultry processing plant in southern Tehran, Iran, in a hot season in 2015. The sampling was performed at two stages, namely post-chilled washing and after 4 h of transportation. In the latter stage, the samples were selected from three vehicles with three types of temperatures. These vehicles included a pickup (18-24 oC), a refrigerated car (4-5 oC), and a refrigerated vehicle with switched off refrigerator (10-14 oC). According to the results, the whole body carcass samples transported at the pickup temperature had the highest mean total count (18.63×106±2.82×106 cfu.ml-1) and was greater (P<0.05) than the standard limit (5×106). On the other hand, the samples carried by the vehicle with switched off refrigerator had the lowest total count (0.65±0.04×106 cfu.ml-1). Similar results were obtained for S. aureus; accordingly, it reached the maximum (333.0±30.73 cfu.ml-1) at 18-24 oC, which was lower than the national standard limit even after 4 h of transportation. In addition, the cfu values for the total count and S. aureus sampled from the chicken carcasses were lower than the national standard level even after 4 h of carcass transportation, with the exception of Salmonella spp. at the three vehicle temperatures and E. coli at the pickup temperature. It was suggested that the transportation temperature of less than 10-14 oC could not affect the fresh chicken carcass to be contaminated with S. aureus and E. coli.