Application of a novel phage LPCS28 for biological control of Cronobacter sakazakii in milk and reconstituted powdered infant formula

Contamination of infant formula with Cronobacter sakazakii (C. sakazakii) can cause fatal infections in neonates. Phages have emerged as promising antibacterial agents for food safety, but their effectiveness may be limited by thermal processing. In this study, we isolated 27 C. sakazakii phages from environmental water samples and selected LPCS28 due to its broad lysis spectrum. The titer of LPCS28 will not be significantly affected by heating at a temperature of 60 degrees C for one hour. In both reconstituted powdered infant formula (RPIF) and liquid milk, the pre-added LPCS28, after the thermal processing at 63 degrees C for 30 min, significantly inhibited the postcontaminated C. sakazakii (103 CFU/mL) and eventually reduced the number of C. sakazakii to below the limit of detection (<10 CFU/mL) within 9 h at 37 C and significantly delayed the increase of bacterial concentration in the samples at 23 degrees C. The phylogenetic analysis revealed that LPCS28 belonged to a new genus, we proposed as Nanhuvirus, under the family Straboviridae. These findings suggest that phage LPCS28 is a promising biological control agent for pathogenic C. sakazakii in the dairy industry.

Automated summary

In this study, a phage termed LPCS28 with a broad lysis spectrum against C. sakazakii was isolated from environmental water samples. LPCS28 showed high thermal stability, with no significant decrease in titer after heating at 60 degrees C for one hour. Upon thermal processing at 63 degrees C for 30 min, LPCS28 effectively inhibited C. sakazakii in reconstituted powdered infant formula and liquid milk, reducing its concentration to below the limit of detection within 9 h at 37 degrees C. Phylogenetic analysis classified LPCS28 as a new genus, Nanhuvirus, within the family Straboviridae. These results highlight the potential of LPCS28 as a biological control agent against pathogenic C. sakazakii in the dairy industry.