Microbiological Quality of Commercial Enteral Formulas and Investigation of Antibacterial and Antioxidant Effects of Thyme, Saffron, and Turmeric Extract Mixture

Abstract

BACKGROUND: The consumption of commercial enteral formulas (CEFs) is increasing worldwide. Given the possibility of contamination of these formulas during preparation and consumption, it is crucial to utilize antimicrobial substances to enhance the safety and quality of them. This study aims to assess the (i) microbiological quality of CEFs and (ii) antibacterial and antioxidant effects of thyme, saffron, and turmeric extract mixture on CEFs. METHODS: First, 50 samples were collected and analyzed to determine the growth of total viable microorganisms (TVC), coliforms, Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). Then, the minimum inhibitory concentration of the extracts was determined by the microdilution method, and the antibacterial effects of the mixed extracts were measured on 26 samples by TVC at the time of sampling, 2, 4, and 24 hours after preparation. Additionally, the antioxidant activity of the mixed extracts was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. RESULTS: In the microbial analysis of food formulas, S. aureus and E. coli were not observed, but the coliforms contamination (3.67 +/- 0.18 CFU/mL) and TVC (4.29 +/- 0.10 CFU/mL) were higher than the standard of U.S. Food and Drug Administration. Additionally, the mixture of aqueous extract of saffron, turmeric, and thyme demonstrated a significant reduction in microbial load within 24 hours. The DPPH analysis indicated that the aqueous extract mixture increased antioxidant activity (38.7) significantly in comparison to CEFs without extract (19.59) (P value < 0.001). CONCLUSIONS: The results of this study indicate that CEFs exhibit high levels of microbial contamination. The extracts of thyme, saffron, and turmeric, however, have the potential to reduce microbial load and enhance antioxidant activity.