Impact of the residues of detergents and disinfectants used in dairy farms on the results of inhibitor tests for raw milk

Abstract

<p style="text-align:justify;"> <span style="font-size:10.0pt;"><span style="font-family:Tahoma;font-size:12px;">The aim of the study was to determine the impact of residues of detergents and disinfectants on the results of most commonly used inhibitor tests for raw milk. Microbiological test (</span><i><span style="font-family:Tahoma;font-size:12px;">Delvotest SP</span></i><span style="font-family:Tahoma;font-size:12px;">-</span><i><span style="font-family:Tahoma;font-size:12px;">NT</span></i><span style="font-family:Tahoma;font-size:12px;">)</span><i> </i><span style="font-family:Tahoma;font-size:12px;">and three rapid tests (</span><i><span style="font-family:Tahoma;font-size:12px;">Charm </span></i><span style="font-family:Tahoma;font-size:12px;">3</span><i><span style="font-family:Tahoma;font-size:12px;"> MRL BL</span></i><span style="font-family:Tahoma;font-size:12px;">/</span><i><span style="font-family:Tahoma;font-size:12px;">TET</span></i><span style="font-family:Tahoma;font-size:12px;">2</span><i><span style="font-family:Tahoma;font-size:12px;">, Charm ROSA MRL BL</span></i><span style="font-family:Tahoma;font-size:12px;">/</span><i><span style="font-family:Tahoma;font-size:12px;">TET and Penzym</span></i><span style="font-family:Tahoma;font-size:12px;">)</span><i> </i><span style="font-family:Tahoma;font-size:12px;">were used in the study</span><i><span style="font-family:Tahoma;font-size:12px;">. </span></i><span style="font-family:Tahoma;font-size:12px;">Three concentrations (recommended by the manufacturer, 10 times lower and twice higher) of</span><i> </i><span style="font-family:Tahoma;font-size:12px;">36 detergents and disinfectants in raw milk were investigated. All methods did not detect concentrations of detergents and disinfectants of alkaline and acid origin 10 times lower than recommended by the manufacturer. 39% of the investigated substances of alkaline origin were detected by </span><i><span style="font-family:Tahoma;font-size:12px;">Delvotest SP</span></i><span style="font-family:Tahoma;font-size:12px;">-</span><i><span style="font-family:Tahoma;font-size:12px;">NT </span></i><span style="font-family:Tahoma;font-size:12px;">and</span><i><span style="font-family:Tahoma;font-size:12px;"> Penzym</span></i><span style="font-family:Tahoma;font-size:12px;">;</span><i><span style="font-family:Tahoma;font-size:12px;"> Charm </span></i><span style="font-family:Tahoma;font-size:12px;">tests</span><i> </i><span style="font-family:Tahoma;font-size:12px;">showed non-typical results only.</span><i><span style="font-family:Tahoma;font-size:12px;"> Delvotest SP-NT</span></i><span style="font-family:Tahoma;font-size:12px;"> did not detect substances of acid origin; </span><i><span style="font-family:Tahoma;font-size:12px;">Penzym</span></i><span style="font-family:Tahoma;font-size:12px;"> detected 50% of these substances, </span><i><span style="font-family:Tahoma;font-size:12px;">Charm </span></i><span style="font-family:Tahoma;font-size:12px;">tests</span><i> </i><span style="font-family:Tahoma;font-si...

Detection of antibiotics in goat's milk: effect of detergents on the response of microbial inhibitor tests

“…These results agree with Zvirdauskiene & Salomskiene (2007) and Salomskiene et al (2013) who studied the effects of various commercial detergents on the microbial test response in cow milk, and found positive results at alkaline detergent concentrations equivalent to the dose recommended by the manufactures and above. Although, it should be noted that these high concentrations are very unlikely to be found in practice, even with poor cleaning routines.…”

Evaluation of false positive results in microbial inhibitor tests for screening antibiotics in goat milk

“…Besides, at these concentrations, the pH of the milk samples was high, reaching pH of 9.82-10.80 for the highest concentrations tested, which could also inhibit the growth of the microorganism and thus, prevent the colour change of the test indicator system. These results agree with the results obtained by Zvirdauskiene and Salomskiene (2007) and Salomskiene et al (2013) who studied the effects of various commercial detergents on the microbial test response in cow milk, and found false positive results at alkaline detergent concentrations equivalent to the dose recommended by the manufactures and above. Although, it should be noted that these high concentrations are very unlikely to be found in practice, even with poor cleaning routines.…”

“…Also, these authors did not find interferences due to the presence of acid detergents in milk. At lower alkaline detergent concentrations (≤ 1,000 mg/l), and Salomskiene et al (2013) did not find any positive results for the Delvotest microbial test.…”

“…Žvirdauskiene and Salomskiene (2007) and Salomskiene et al (2013) found false positive results at alkaline detergent concentrations equivalent to the dose recommended by the manufactures and above. Also, these authors did not find interferences due to the presence of acid detergents in milk.…”

“…Some authors (Zvirdauskiene and Salomskiene, 2007;Salomskiene et al, 2013) only found false positive results at very high concentrations of alkaline detergents, equal or superior to the dose recommended by the manufacturers. However, Schiffmann et al (1992) obtained non-compliant results at lower concentrations (0.01%), whereas for these concentrations did not obtain any positive results, although they employed a limited number of cleaning products and microbial methods.…”