Inhibition of Pectobacterium carotovorum-mediated potato soft rot by carboxymethyl cellulose-based antibacterial edible coating containing green tea extract.

This study was conducted to propose a new strategy for preventing Pectobacterium carotovorum-mediated potato soft rot through the development of a carboxymethyl cellulose (CMC)-based antibacterial coating incorporated with green tea extract (GTE). GTE/CMC films resulted in increased water vapor permeability due to the incorporation of polar groups in GTE. In the antibacterial test against P. carotovorum, the MBC value of GTE was 2 mg/mL. The time-kill assay demonstrated that GTE/CMC (2 × MBC) completely eradicated bacteria within 0.5 h (~6.4 log CFU/mL reduction). The potential of GTE/CMC to prevent potato soft rot was evaluated by monitoring the potato appearance, maceration area, and texture properties. The GTE/CMC-coated potatoes exhibited significantly reduced maceration area and remained firm for 3 days. Moreover, there was no change in the antimicrobial efficacy for 8 weeks. The developed GTE/CMC could be used as a biological coating system for postharvest storage and soft rot prevention. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-024-01548-6.

Evaluation of the biocontrol potential of a collagen peptide/trehalose-based Cronobacter sakazakii phage powder in rehydrated powdered infant formula.

Cronobacter sakazakii is a major foodborne pathogen that is mainly transmitted through powdered infant formula (PIF) and has a high mortality rate of up to 80%, particularly in fetuses and neonates. Bacteriophages have emerged as an effective biocontrol agent for antibiotic-resistant bacteria. In this study, lytic phage SG01 was newly characterized and loaded into collagen peptide/trehalose-based powders to develop an antibacterial agent against C. sakazakii contamination in PIF. The phage belongs to the Siphoviridae family, has an icosahedral head and a flexible tail, and showed rapid and persistent antibacterial activity up to 17 h. It was specifically active against C. sakazakii and also exhibited effective anti-biofilm properties. The phage was freeze-dried to a collagen peptide/trehalose-based powder and the phage was tested for viability, storage stability, and antibacterial activity. The optimal composition was 5% (w/v) collagen peptides and 1% (w/v) trehalose, which demonstrated the highest phage viability after freeze-drying. The phage remained stable in the collagen peptide/trehalose-based powder for up to four weeks at 4 °C and 25 °C, indicating that this is a desirable formulation for phage protection. Furthermore, the phage powder showed significant antibacterial efficacy in PIF, with a 4-log CFU/mL reduction within 6 h. Overall, the tested phage powder has the potential to be used as an antimicrobial agent in the food industry, particularly in powdered foods such as PIF.

Comparison of chitosan and gelatin-based films and application to antimicrobial coatings enriched with grapefruit seed extract for cherry tomato preservation.

Bio-based single, composite, and bilayer edible films were developed based on chitosan and gelatin, including grapefruit seed extract (GSE) as an antimicrobial agent. The physicochemical and antimicrobial properties of films were analyzed, and it was found that compounding and laminating two polymers could enhance their physicochemical properties. The composite film was strong, endurable, and flexible compared with the single ones. In addition, the composite and bilayer films had lower water vapor permeability than the single ones. Edible films and coatings with GSE presented a greater bactericidal effect than the inactive ones. In addition, the hardness, weight, and color changes of the coated cherry tomatoes during 7-day storage did not differ, whereas a bacterial reduction against Salmonella Typhimurium was revealed. Taken together, composite and bilayer films with CH and GL and enriched with GSE were developed for food packaging applications, and it showed improved mechanical, water barrier, and antimicrobial properties. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01254-9.

Complete Genome Sequence of the Bacillus cereus Temperate Bacteriophage BSG01.

The Bacillus cereus phage BSG01 has a siphovirus morphology that can belong to the order Caudovirales. It consists of 81,366 bp, with a GC content of 34.6%, and contains 70 predicted open reading frames. BSG01 includes lysogeny-related genes (tyrosine recombinase and antirepressor protein), indicating that it is a temperate phage.