Food safety in raw milk production: risk factors associated to bacterial DNA contamination

Cerva, Cristine; Bremm, Carolina; Reis, Emily Marques dos; Bezerra, André Vinícius Andrade; Loiko, Márcia Regina; Cruz, Cláudio Estêvão Farias da; Cenci, Alexander; Mayer, Fabiana Quoos

doi:10.1007/s11250-014-0580-y

Cited by 24 publications

(12 citation statements)

References 19 publications

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“…may indicate that there could be different risk factors associated with contamination of milk between the two regions. A recent report from Brazil signified that there was a difference in contamination index of milk by a range of pathogens between two different geographical locations in which different risk factors such as temporary cattle confinement, low milk production, low milking machine cleaning frequency, and milk storage area without tile walls were identified specifically for each study region [23].…”

Section: Discussionmentioning

confidence: 99%

Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia

Seyoum

Woldetsadik

Mekonen

et al. 2015

J Infect Dev Ctries

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Introduction: Listeria monocytogenes is of major significance in human and veterinary medicine. Most human Listeria infections are foodborne and the association of contaminated milk and dairy produce consumption with human listeriosis is noteworthy. In Ethiopia, there is limited data regarding the prevalence of L. monocytogenes in raw bovine milk and dairy products. The aim of this study was, therefore, to determine the prevalence of L. monocytogenes in raw bovine milk and dairy produce. Methodology: A total of 443 milk and milk product samples were microbiologically analyzed following methods recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual to isolate Listeria spp. Results: The overall prevalence of Listeria spp. was 28.4% and specifically that of L. monocytogenes was 5.6%. Taking the prevalence of Listeria spp. into consideration, cheese was found to be highly contaminated at 60%, followed by pasteurized milk samples (40%), raw milk (18.9%) and yoghurt (5%). Considering the prevalence of Listeria monocytogenes only, raw milk had the lowest contamination while cheese had the highest, followed by pasteurized milk and yoghurt. Conclusions: Raw milk and milk products produced in urban and peri-urban areas of central Ethiopia were contaminated with pathogenic bacteria, L. monocytogenes. The detection of this pathogen in raw milk and milk products warrants an urgent regulatory mechanism to be put in place and also the potential role of milk processing plants in the contamination of dairy products should be investigated.

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Section: Discussionmentioning

confidence: 99%

Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia

Seyoum

Woldetsadik

Mekonen

et al. 2015

J Infect Dev Ctries

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“…in bat kidneys, total DNA was extracted as previously described [21] and quantified using a spectrophotometer (L-quant, Loccus Biotechnology, Brazil). A conventional PCR for Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene was performed for DNA quality confirmation [22]. About 25 ng of DNA were used as template for Taqman ® real-time PCR with primers and probe targeting lipL32 as previously published [23].…”

Section: Molecular Detection Of Pathogenic Leptospira Sppmentioning

confidence: 99%

Pathogenic Leptospira spp. in bats: Molecular investigation in Southern Brazil

Mayer

Reis

Bezerra

et al. 2017

Comparative Immunology, Microbiology and Infectious Diseases

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The present study aimed to investigate the frequency of pathogenic Leptospira spp. in Brazilian bats and to determine possible risk factors associated to it. Ninety two bats of 12 species were evaluated. Whole genomic DNA from kidneys was extracted and real-time PCR specific to pathogenic Leptospira spp. was applied. Association between the frequency of specimens positive for Leptospira spp. and sex, age, bat species or family, season of collection, geographic localization and feeding habits was evaluated. The results showed that 39.13% of analyzed bats were found positive for Leptospira spp. Nine bat species had at least one positive result. There was no association among the evaluated variables and frequency of pathogenic Leptospira spp. Although the limitations due to lack of Leptospira spp. isolation, leptospiral carriage was demonstrated in bats of different species from southern Brazil, which reinforces the need for surveillance of infectious agents in wild animals.

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“…DNA was eluted in 30µL of 1 x TE and quantified at Nanodrop 1000 (Thermo Fisher Scientific, Wilmington, DE, USA). A conventional PCR for Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene was performed as described by Cerva et al (2014) to confirm the absence of inhibitors in DNA; then, the suitable samples were subjected to a SYBR ® Green (Invitrogen, Carlsbad, CA, USA) real-time PCR able to differentiate, with the same primer pair, between Mycobacterium tuberculosis and Mycobacterium avium complexes by the melting temperature (90.1°C and 92.7°C, respectively -Supplementary Fig.1) (Jaime et al 2010, Bezerra et al 2015. The reactions were performed in duplicate at StepOne thermocycler (Life Technologies, USA) with 6.25µL of Platinum ® SYBR ® Green qPCR SuperMix-UDG (Applied Biosystems, USA), 0.2µM of each primer, 0.5µL of ROX and ultra-pure water to a final volume of 12.5µL.…”

Section: Methodsmentioning

confidence: 99%

Nasal swab real-time PCR is not suitable for in vivo diagnosis of bovine tuberculosis

et al. 2017

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RESUMO.-[A PCR em tempo real de swab nasal não é adequada para o diagnóstico in vivo de tuberculose bovina.] A tuberculose bovina (bTB) é uma zoonose que causa perdas econômicas e riscos à saúde pública em muitos países. O diagnóstico da doença em animais vivos é realizado pelo teste intradérmico da tuberculina, que é baseado em reações de hipersensibilidade tardia. Como a tuberculose tem resposta imunológica complexa, este teste tem limitações em termos de sensibilidade e especificidade. Este estudo procurou desenvolver uma abordagem alternativa para o diagnóstico in vivo da tuberculose bovina, com base na reação em cadeia da polimerase (PCR) em tempo real. Bovine tuberculosis (bTB) is a zoonosis causing economic losses and public health risks in many countries. The disease diagnosis in live animals is performed by intradermal tuberculin test, which is based on delayed hypersensitivity reactions. As tuberculosis has complex immune response, this test has limitations in sensitivity and specificity. This study sought to test an alternative approach for in vivo diagnosis of bovine tuberculosis, based on real-time polymerase chain reaction (PCR). DNA samples, extracted from nasal swabs of live cows, were used for SYBR ® Green real-time PCR, which is able to differentiate between Mycobacterium tuberculosis and Mycobacterium avium complexes. Statistical analysis was performed to compare the results of tuberculin test, the in vivo gold standard bTB diagnosis method, with realtime PCR, thereby determining the specificity and sensitivity of molecular method. Cervical comparative test (CCT) was performed in 238 animals, of which 193 had suitable DNA from nasal swabs for molecular analysis, as indicated by amplification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene, and were included in the study. In total, 25 (10.5%) of the animals were CCT reactive, of which none was positive in the molecular test. Of the 168 CCT negative animals, four were positive for M. tuberculosis complex at real time PCR from nasal swabs. The comparison of these results generated values of sensitivity and specificity of 0% and 97.6%, respectively; moreover, low coefficients of agreement and correlation (-0.029 and -0.049, respectively) between the results obtained with both tests were also observed. This study showed that real-time PCR from nasal swabs is not suitable for in vivo diagnosis of bovine tuberculosis; thus tuberculin skin test is still the best option for this purpose.

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Food safety in raw milk production: risk factors associated to bacterial DNA contamination

Cited by 24 publications

References 19 publications

Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia

Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia

Pathogenic Leptospira spp. in bats: Molecular investigation in Southern Brazil

Nasal swab real-time PCR is not suitable for in vivo diagnosis of bovine tuberculosis

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