The occurrence of Cronobacter spp. was investigated in table eggs and egg-based desserts obtained from retail stores. Cronobacter was isolated from 57 out of 180 (31.7%) (95% Confidence Interval [CI]: 26–43%) examined samples of eggs and egg-based desserts. The prevalence of Cronobacter spp. was significantly higher in farm eggs (67%) (P < 0.05) than in Balady eggs (23%), cream cake (27%) and small-scale ice cream (27%). Cronobacter (C.) sakazakii and C. muytjensii were the predominant isolates obtained in the present study. All C. sakazakii isolates were molecularly confirmed with higher incidence in small-scale ice cream (62.5%).

Tallaga cheese is the most popular type of white soft cheese in Egypt. Cronobacter sakazakii is an opportunistic foodborne pathogen that poses a threat to the health of almost every age group, with a particular emphasis on neonates and infants. Essential oils (EOs), such as olive oil and thyme oil, exhibit a broad-spectrum antibacterial effect. However, few studies have investigated the antibacterial activity of these EOs and their formulated nanoemulsions (NEs)—olive oil nano-emulsions (ONE) and thyme oil nano-emulsions (TNE)—on C. sakazakii in cheese to date. The purpose of this study was to investigate the inhibitory effects of these EOs and their NEs on the development of C. sakazakii during the processing and storage of Tallaga cheese. Additionally, the organoleptic properties of the resulting cheese were evaluated. Herein, ONE and TNE were prepared and characterized using a zetasizer and transmission electron microscopy (TEM). Furthermore, the minimum inhibitory concentrations (MICs) of EOs and NEs were determined using well diffusion assay. Fresh buffalo's milk for the elaboration of Tallaga cheese was inoculated with C. sakazakii at a concentration of 6 logCFU/mL, along with the addition of MICs of either EOs or NEs. The obtained results showed that the MICs were 15mg/mL (v/v) for either olive oil, thyme oil, ONE and TNE with diameter inhibition zones of 10.3±0.5, 13.3±1.7, 12.3±0.5, and 16±0.8mm, respectively. In addition, NEs exhibited high antibacterial activities against C. sakazakii in comparison to pure EOs. Particularly, the strongest antibacterial effect toward C. sakazakii was reported with TNE during manufacturing and storage of Tallaga cheese. Overall, these results suggest that thyme and its NEs have the potential toprevent bacterial contamination by C. sakazakii in the dairy industry.