Antibiotic residues in milk and milk products: A momentous challenge for the pharmaceutical industry and medicine

Table 1 Chromatographic scheme

Thin-layer plate	Adsorbent	Amount of sample applicated in μL	Solvent	Test organism
1	Kieselguhr	30	A	B. cereus
2	Silica gel	30	B	M. flavus
3	Silica gel	30	C	S. lutea
4	Silica gel	30	C	B. subtilis
5	Silica gel	30	D	M. flavus
6	Cellulose	10	E	B. cereus

B. cereus: Bacillus cereus; M. flavus: Micrococcus flavus; S. lutea: Sarcina lutea; B. subtilis: Bacillus subtilis.

Table 2 R_f values of antibiotics on the different plates

Antibiotic	Plate
	1	2	3	4	5	6
Cloxacillin	-	-	0.70	0.70	-	0
Dihydrostreptomycin	-	-	-	-	-	0.40
Tetracycline	0.35	0	0	0	0	-
Oxytetracycline	0.20	0	0	0	0	-
Chlortetracycline	0.60	0	0	0	0	-
Chloramphenicol	0	0.70	0.65	0.65	0.80	-
Neomycin	-	-	-	-	-	0
Novobiocin	-	0.80	0.80	0.80	0.80	-
Bacitracin	-	0.45	-	-	-	-
Erythromycin	0.20	0.70	0.35	0.35	0.25	-
Oleandomycin	0.20	0.70	0.35	-	0.25	-
Ampicillin	0.35	-	0.50	-	-	-
Streptomycin	-	-	-	-	-	0.50
Oxacillin	0	-	0.60	0.60	-	-

Table 3 Azithromycin degradation constant rate k values at different temperatures[10]

Time in h	4 °C	37 °C	70 °C	100 °C
1	1000 ± 8e	50 ± 1a	50 ± 2a	200 ± 3a
3	333 ± 3d	966 ± 9d	4033 ± 22e	3900 ± 18e
6	250 ± 2c	933 ± 8d	2000 ± 15d	2033 ± 16d
12	116 ± 2b	516 ± 7c	1025 ± 8c	1000 ± 6c
24	62 ± 2a	270 ± 4b	537 ± 5b	533 ± 4b

^aDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard error of triplicate samples.

^bDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard error of triplicate samples.

^cDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard error of triplicate samples.

^dDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard error of triplicate samples.

^eDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard error of triplicate samples.

Table 4 Tetracycline degradation constant rate k values at different temperatures[10]

Time in h	4 °C	37 °C	70 °C	100 °C
1	20 ± 4a	50 ± 6a	30 ± 6a	60 ± 15a
3	256 ± 32e	400 ± 46e	630 ± 81e	860 ± 61e
6	163 ± 17cd	290± 23cd	360 ± 17cd	510 ± 46d
12	116 ± 26c	225 ± 12c	300 ± 26c	340 ± 32c
24	50 ± 8b	135 ± 20b	160 ±18b	160 ± 02b

^aDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard deviation of triplicate samples.

^bDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard deviation of triplicate samples.

^cDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard deviation of triplicate samples.

^dDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard deviation of triplicate samples.

^eDifferent letters indicate statistically significant differences at P < 0.05 according to a Turkey’s honest significant difference post hoc test. Values are mean ± standard deviation of triplicate samples.