Heat treatment effects on the antimicrobial activity of macrolide and lincosamide antibiotics in milk.

Antibiotic residues in milk can cause serious problems for consumers and the dairy industry. Heat treatment of milk may diminish the antimicrobial activity of these antibiotic residues. This study analyzed the effect of milk processing (60 °C for 30 min, 120 °C for 20 min, and 140 °C for 10 s) on the antimicrobial activity of milk samples fortified with three concentrations of three macrolides (erythromycin: 20, 40 and 80 μg/liter; spiramycin: 100, 200, and 400 μg/liter; and tylosin: 500, 1,000, and 2,000 μg/liter) and one lincosamide (lincomycin: 1,000, 2,000, and 4,000 μg/liter).

Effect of heat treatments on aminoglycosides in milk.

The presence of antibiotic residues in milk not only is a potential consumer risk but also may cause serious problems in the fermentation processes used in the dairy industry. There is very limited information available on the effect of heat treatments on aminoglycoside activity in milk. For this reason, the objective of this study was to analyze the effect of different heat treatments (60 degrees C for 30 min, 120 degrees C for 20 min, and 140 degrees C for 10 s) on milk samples spiked with four aminoglycosides (gentamicin, 50, 100, and 200 microg/liter; kanamycin, 300, 600, and 1200 microg/liter, neomycin, 200, 400, and 800 microg/liter; and streptomycin, 200, 400, and 800 microg/liter).

Heat inactivation of beta-lactam antibiotics in milk.

The presence of residues of antimicrobial substances in milk is one of the main concerns of the milk industry, as it poses a risk of toxicity to public health, and can seriously influence the technological properties of milk and dairy products. Moreover, the information available on the thermostability characteristics of these residues, particularly regarding the heat treatments used in control laboratories and the dairy industry, is very scarce. The aim of the study was, therefore, to analyze the effect of different heat treatments (40 degrees C for 10 min, 60 degrees C for 30 min, 83 degrees C for 10 min, 120 degrees C for 20 min, and 140 degrees C for 10 s) on milk samples fortified with three concentrations of nine beta-lactam antibiotics (penicillin G: 3, 6, and 12 microg/liter; ampicillin: 4, 8, and 16 microg/liter; amoxicillin: 4, 8, and 16 microg/liter; cloxacillin: 60, 120, and 240 microg/liter; cefoperazone: 55, 110, and 220 microg/liter; cefquinome: 100, 200, and 400 microg/liter; cefuroxime: 65, 130, and 260 microg/liter; cephalexin: 80, 160, and 220 microg/ liter; and cephalonium: 15, 30, and 60 microg/liter).

Biological response modifiers in the small bowel allograft rejection.

Immunological response is an interlinking network of stimuli and response signals. Rejection includes a complex series of events that depends on the interaction of many cells and soluble mediators--cytokines--and other biological response modifiers--among these, prostaglandins and hormones. In small bowel transplantation rejection, the role of "biological response modifiers" may be especially important because cytokines act on both "antigens presenting cells" from the recipient and "passenger lymphocytes" from the donor, in addition cytokines play a central role in the pathogenesis of clinical acute graft versus-host disease.