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Inactivation of Enterobacter sakazakii in reconstituted infant formula by monocaprylin
Manoj Kumar Mohan Nair1, Jennifer Joy, Kumar S Venkitanarayanan
1Department of Animal Science, Unit-4040, University of Connecticut, Storrs, Connecticut 06269, USA.
Insights
Monocaprylin, derived from caprylic acid, effectively reduced the population of the pathogen Enterobacter sakazakii in infant formula. This finding suggests monocaprylin
Area of Science:
- Food Safety
- Microbiology
- Public Health
Background:
- Enterobacter sakazakii is an emerging pathogen causing severe infections in neonates and children, with infant formula identified as a primary source.
- Caprylic acid, a fatty acid found in milk, is recognized as safe by the FDA.
Purpose of the Study:
- To evaluate the antibacterial efficacy of monocaprylin, an ester of caprylic acid, against Enterobacter sakazakii in reconstituted infant formula.
Main Methods:
- A five-strain mixture of E. sakazakii was inoculated into infant formula and treated with varying concentrations of monocaprylin.
- Samples were incubated at different temperatures (37, 23, 8, and 4°C) and time points (0-48 hours).
- Surviving populations of E. sakazakii were quantified to assess the antimicrobial effect.
Main Results:
- Monocaprylin significantly reduced E. sakazakii populations compared to controls (P < 0.05).
- A 50 mM concentration of monocaprylin achieved a >5 log CFU/ml reduction within 1 hour at 37°C or 23°C.
- Significant reductions were also observed within 24 hours at lower temperatures (8°C or 4°C).
Conclusions:
- Monocaprylin demonstrates potential as an agent to inactivate Enterobacter sakazakii in reconstituted infant formula.
- Further sensory evaluation is necessary to determine the feasibility of its application in infant formula.
Abstract:
Enterobacter sakazakii is an emerging pathogen that causes meningitis, bacteremia, sepsis, and necrotizing enterocolitis in neonates and children, with a mortality rate of 14%. Epidemiological studies have implicated dried infant formula as the principal source of the pathogen. Caprylic acid is a natural eight-carbon fatty acid present in breast milk and bovine milk and is approved as generally recognizable as safe by the U.S. Food and Drug Administration. The objective of this study was to determine the antibacterial effect of monocaprylin (monoglyceride ester of caprylic acid) on E. sakazakii in reconstituted infant formula. A five-strain mixture of E. sakazakii was inoculated into 10-ml samples of reconstituted infant formula (at 6.0 log CFU/ml) followed by 0, 25, or 50 mM (1%) monocaprylin. The samples were incubated at 37 or 23 degrees C for 0, 1, 6, and 24 h and at 8 or 4 degrees C for 0, 6, 24, and 48 h, and the surviving populations of E. sakazakii at each sampling time were counted. The treatments containing monocaprylin significantly reduced the population of E. sakazakii (P < 0.05) compared with the controls. Monocaprylin (50 mM) reduced the pathogen by >5 log CFU/ml by 1 h of incubation at 37 or 23 degrees C and by 24 h of incubation at 8 or 4 degrees C. Results indicate that monocaprylin could potentially be used to inactivate E. sakazakii in reconstituted infant formula; however, sensory studies are warranted before its use can be recommended.
