Antibacterial activity of crocin-loaded niosomes against foodborne pathogens isolated from cream pastries

Cream pastries, due to their high moisture and nutrient content, are susceptible to growth of foodborne pathogens, which endanger human health. Crocin, an apocarotenoid glycoside from saffron (Crocus sativus), exhibits broad-spectrum antimicrobial activity. This study aimed to isolate food-derived strains of common foodborne bacteria, including Staphylococcus aureus, Escherichia coli, and Bacillus cereus, from cream pastries collected in Iran, and to comparatively evaluate the in vitro antibacterial activity of crocin in free and niosome-encapsulated forms. A total of 178 cream pastry samples were analyzed for microbial contamination. Target bacteria were isolated, cultured, and identified by standard routine microbiological techniques. Crocin-loaded niosomes prepared by the thin-film hydration method formed nano-sized vesicles (139 ± 0.7 nm), with a morphology, surface charge (zeta potential: +9.9 ± 0.5 mV), and a high encapsulation efficiency (72 ± 0.5%) and a sustained in vitro release profile over 48 h (up to 53% cumulative release at pH 6.8). The antibacterial activity of free and encapsulated crocin against isolated pathogens was assessed by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which were treated as discrete, stepwise endpoints and reported descriptively. S. aureus was detected in 2 (1.1%), E. coli in 1 (0.56%), and B. cereus in 1 (0.56%) of samples. Niosomal crocin exhibited lower MIC and MBC values against S. aureus and E. coli compared to free crocin, corresponding to a two-fold reduction in MIC. In contrast, no difference in MIC or MBC values was observed for B. cereus. Niosomal encapsulation enhances the physicochemical stability of crocin and improves its antibacterial performance against Gram-positive and Gram-negative foodborne pathogens, offering a biocompatible, natural antimicrobial strategy for improving microbial safety of perishable foods such as cream pastries. Future studies should investigate the underlying mechanisms, such as biofilm disruption and membrane permeabilization, and evaluate the efficacy in real food matrices.