Table 1.

List of bacterial strains under study.

Species	Strain	Gram characteristics	Origin	Culture conditions
Escherichia coli	K12 MG1655	Gram-negative	Laboratory strain	LB medium, 37°C with shaking
	ATCC8739		Commensal, isolated from infant feces
	CEC15		Commensal, isolated from a conventional suckling rat intestine
Lactobacillus rhamnosus	GG	Gram-positive	Commensal, isolated from a healthy human intestine	MRS medium, 37°C without shaking
Lactobacillus sakei	23K	Gram-positive	Food (meat)	MRS medium, 30°C without shaking
Lactococcus lactis subsp. cremoris	IBB477	Gram-positive	Food (raw milk)	M17 medium supplemented with glucose 0.5% (m/v), 30°C without shaking
Lactococcus lactis subsp. lactis	TIL448		Food (peas)
Streptococcus thermophilus	LMD-9	Gram-positive	Food (yogurt)	M17 medium supplemented with lactose 1% (m/v), 37°C without shaking