Effect of heat treatments in the degradation of antibiotics in milk.

D. Escobar

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06-24-2020

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Abstract:

W31
Effect of heat treatments in the degradation of antibiotics in milk.
D. Escobar*¹, R. Pelaggio¹, S. Moreno¹, G. Cardozo¹, E. De Torres³, F. Rey¹, L. Olazabal². ¹Latitud, Fundaciï¿½n LATU Montevideo, Uruguay, ²Laboratorio Tecnolï¿½gico del Uruguay Montevideo, Uruguay, ³Campo experimental Nï¿½2, Facultad de Veterinaria, UdelaR San Jose, Uruguay.

Antibiotics are used in dairy farms for the treatment and prevention of diseases in dairy cattle, such as mastitis, lameness, respiratory infections and diarrhea. Antibiotic residues in milk can generate problems in the population in the form of allergies and antimicrobial resistance, as well as in industry and the environment. There are international regulations that prohibit the processing of milk with antibiotics. The relevance of possible heat-inactivation of β-lactam and tetracyclines residues in milk for the final disposal or food safety is important when making decisions when the milk is contaminated. The aim of this work was to study the effect of temperature and time on the degradation of 15 β-lactam antibiotics and 3 tetracyclines in milk using an HPLC-MS/MS. The trials were performed on raw whole milk contaminated with 100 ppb antibiotic concentrations. The effect of different temperatures (63 and 80ï¿½C) was studied during 2 different times (30 and 60 min). The degradation percentages of β-lactam and tetracyclines in milk are shown in Table 1. The results indicate that milk subjected to a thermal treatment of 63ï¿½C for 30 min, 11 of the 18 antibiotics studied degrade less than 25%, higher percentages were found in tetracycline (43%), cefoperazone (44%), cephapirin (49%), cefuroxime (53%) and cefacetrile (62%). Degradation percentages greater than 95% were found with the use of 80ï¿½C for 60 min, in cephapirin, cefacetrile, cefuroxime and cefoperazone. The knowledge of the effects of different thermal treatment conditions on antibiotic residues in milk will allow the development of tools and possible strategies that minimize risks to the environment and food safety.Table 1.

Antibiotic	Degradation¹ (%)
63ï¿½C			80ï¿½C
30 min	60 min	30 min	60 min
Amoxicillin	15^a	15^a		18^a	38^a
Dicloxacillin	27^a	22^a		24^a	47^b
Cloxacillin	18^a	14^a		14^a	34 ^b
Ampicillin	13^a	14^a		19^a	39^b
Penicillin G	20^a	17^a		22^a	27^a
Oxacillin	12^a	10^a		10^a	31^a
Cefapirin	49^a	50^a		85^b	97^c
Cephalexin	15^a	26^b		44^c	67^d
Cefazolin	13^a	11^a		10^a	32^b
Cefalonium	24^a	20^a		49^b	73^c
Cefacetrile	62^a	71^a		87^b	100^b
Cefuroxime	53^a	54^a		81^b	95^b
Ceftiofur	29^a	30^a		52^b	70^c
Cefoperazone	44^a	48^a		80^b	96^b
Cefquinome	24^a	26^a		37^b	64^c
Oxytetracycline	23^a	30^ab		37^b	67^c
Tetracycline	43^a	44^a		45^a	66^b
Doxycycline	24^a	26^ab		29^b	51^c

^a—dDifferent superscripts in the same row indicate significant differences (P <0.05).¹Values are means of triplicate analysis.

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