Quorum Sensing and Spoilage Potential of Psychrotrophic Enterobacteriaceae Isolated from Milk

Table 5

Summary of identification by high-performance liquid chromatography positive electrospray ionization (ESI⁺-) MS of AHLs produced by H. alvei 059, 068, and 071, Enterobacter sp. 067, and A. hydrophila 099.

Standard	[M+H]^+1	Retention time of AHL molecules [min]
		Standard mix Calibration^1	067	068	071	099	Standard mix Calibration	059
C4-HSL	172	5.5	-^3	-	-	5.8	4.29	-
3-hydroxy-C4-HSL	188	Nd^2	-	4.6	-	-	Nd	-
C5-HSL	186	Nd	-	-	-	7.8	Nd	-
3-Oxo-C6-HSL	214	6.6	-	6.5	6.6	-	4.57	4.55
C6-HSL	200	10.9	-	10.9	11.0	10.9	9.69	9.45
3-Oxo-C8-HSL	242	12.5	-	12.5	12.5	-	11.18	11.16
C8-HSL	228	15.3	-	-	15.4	-	14.26	14.2
3- hydroxy-C12-HSL	300	Nd	-	17.2	17.2	-	Nd	-
C10-HSL	256	18.6	-	-	-	-	17.59	-
3-Oxo-C12-HSL	298	19.0	-	-	-	-	Nd	-

M+H]⁺, mass to charge rate. ²Nd, not determined. ³Nothing found.