Fig 1.
Phage cocktail biocontrol on tomato surface.
Tomatoes were sprayed with the microencapsulated phage cocktail and then inoculated with E. coli O157:H7 and stored at 4°C for different times. Data represents mean values ± SEM of two independent experiments. *, P<0.05 compared to tomatoes non-treated with the microencapsulated phage cocktail.
Fig 2.
Stability of microencapsulated and free phages at different storage temperatures.
Microencapsulated (ME) and free phages were stored at low (A) and high (B) temperatures for different times. Data represents mean values ± SEM of three independent experiments. Right, interaction plot of phage survival means calculated for timepoint at each phage condition. Different letters represent significant differences between groups (P<0.02), whereas letters shared in common between or among the groups indicate no significant differences.
Fig 3.
Effects of UV light and pH on the survival of microencapsulated and free phages.
Microencapsulated (ME) and free phages were exposed to UV light for 15 and 30 min (A) or incubated at different pH values for 5 min at 37°C (B). Values are expressed as the phage survival percentage and represents mean ± SEM of three independent experiments. *, P<0.001; **, P<0.05 compared to free phages.
Fig 4.
Effects of simulated gastric fluid (SGF) and bile salts (BS) on the survival of microencapsulated and free phages.
Microencapsulated (ME) and free phages were exposed to SGF (A) at different pH values for 2, 5, 15 and 30 min or exposed to BS (B) at 1% and 2% for 1 and 3 h. Data represents mean values ± SEM of three independent experiments. Right, interaction plot of phage survival means calculated for timepoint at each phage condition. Different letters represent significant differences between groups (P<0.05), whereas letters shared in common between or among the groups indicate no significant differences.
Table 1.
ME phage cocktail stability in simulated intestinal fluid.
Fig 5.
Phage survival after oral administration.
Mice (n = 5 per group) were orally exposed to a single dose of 10, 6, 3 log10 PFU/mL of the free or microencapsulated phage cocktails. The control group included mice treated with mineral water. (A) Faecal shedding after seven days of the administration of the free or microencapsulated phage cocktails at different doses. Results are expressed as mean phage titres ± SEM of two independent experiments. *, P<0.02 compared to free phages. Closed triangles indicate mean phage dose plus baseline phage titres. (B) Percentage reduction in E. coli shedding in free or microencapsulated phage cocktail-treated mice on day 7 was determined relative to baseline counts found in mice before treatment. Values represent mean concentration ± SEM of two independent experiments. Numbers above bars indicate mean log10 CFU/g of E. coli reduction. No significant differences were observed between groups.
Table 2.
In silico analyses of phage proteins potential allergenicity.
Table 3.
In silico analysis of phage proteins with sliding 80mer FASTA hits (FAO/WHO >35%).