scholarly journals Baseline composition and microbial quality assessment of raw milk from endemic small ruminants and Maghrebi camels in the oasis area of Tunisia

Author(s):  
Zahran Khaldi ◽  
Mounir Nafti ◽  
Mohamed Tabarek Jilani

Abstract Characteristics and quality aspects of milk from native ovine queue fine de l’Ouest (QFO) and the local goat population were investigated and compared with those of the local Maghrebi camel. A total of 378 individual milk samples were collected from lactating animals reared in the continental oasis region of Tunisia. Samples were analyzed for physical parameters (pH, density, and acidity), chemical composition (dry matter, fat, protein, lactose, casein, ash, and casein-protein ratio), mineral concentrations (Ca, P, Na, and K) and microbiological features (total mesophilic aerobic bacteria (TMAB), total coliform count (TCC), lactic acid bacteria (LAB), sulphite-reducing Clostridium (CSR), yeast and molds (Y/M), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Salmonella) according to standard methods. The results obtained for milk characteristics revealed noticeable disparities between the three species. The mean values of pH, density, and acidity in milk collected from sheep appeared higher than those in milk collected from goat species. Compared to the camel populations, sheep species produced milk with similar pH but higher density and acidity. Between camel and goat species, pH and acidity were higher in Negga, while the density was similar. For milk composition, the results showed a remarkable variation among all studied species and an obvious superiority of the ovine species over the caprine and camel populations in all the chemical contents being studied, except for the casein-protein ratio, which is in favor of goat species. The milk of QFO sheep, the richest in casein and protein, was expressed with significantly higher levels of calcium and phosphorus than goat and camel milk. Compared to small ruminants, milk from camels is the richest in Na and K. Additionally, more Ca is present in milk from camels than goats. Goat milk, the poorest type of milk in Ca and Na, contains on average more P than camel milk and more K than sheep's milk. The poor bacteriological quality was that of camel milk for all microbial counts. The microbial quality of goat milk was higher than that of ewe milk based on TMAB, TCC, and E. coli counts, while ovine milk was of better quality, referring to LAB, Y/M, and S. aureus values. No significant differences were found for Staphylococcus aureus and Escherichia coli between the examined species. The obtained results highlighted the complete absence of the two dangerous pathogens Salmonella and CSR in all investigated milk samples. The microbiological examination evidenced that the milk of small ruminant species complies with standard criteria required by Tunisian legislation on the hygiene of milk and dairy products. Regarding camel milk, the microbial analysis revealed poor quality that exceeds standard criteria.

2020 ◽  
Vol 8 (3) ◽  
pp. 82-86
Author(s):  
Shyamala Rai ◽  
Barsha Karki ◽  
Sujita Humagain ◽  
Sandesh Rimal ◽  
Sandhya Adhikari ◽  
...  

The emergence of antibiotic resistance in microorganisms and the presence of such isolates in milk pose a great risk to public health. Therefore, this study aims to determine the antibiotic susceptibility pattern of Escherichia coli and Staphylococcus aureus isolated from milk and assess the microbial quality of milk. For this, a total of 70 milk samples were collected and the total bacterial count (TBC) was determined. E. coli and S. aureus were isolated using their respective selective media while antibiotic susceptibility testing was carried out by Kirby Bauer Disc Diffusion method. The TBC showed that the raw milk samples contained two-fold higher microbial load while the pasteurized milk samples contained four-fold higher microbial loads than the standard guidelines. A total of 62 isolates were identified from culture-positive milk samples of which 32 were E. coli and 30 were S. aureus. A significant correlation was observed between microbial load and the organism isolated (r = 0.339, p<0.01). All S. aureus isolates were susceptible to Chloramphenicol while 40% were resistant to Cefoxitin, indicating the presence of Methicillin resistant S. aureus (MRSA). Also, 12 multidrug resistant (MDR) S. aureus were identified. While for E. coli, all were susceptible to Chloramphenicol but resistant to Ampicillin. Also, 9 MDR E. coli were detected. Higher resistance was observed among isolates from the raw milk samples than the pasteurized milk. It can be concluded that the milk produced by small-scale farms and dairy industries of Kathmandu district are of poor quality. Hence, routine microbial quality assessment and antimicrobial resistance monitoring should be followed to safeguard public health.


1986 ◽  
Vol 49 (3) ◽  
pp. 233-235 ◽  
Author(s):  
PATRICIA HAGGERTY ◽  
NORMAN N. POTTER

Studies were made to compare the growth and death of Staphylococcus aureus, Streptococcus faecalis and Escherichia coli in skim milk concentrated by ultrafiltration to that in unconcentrated skim milk. Skim milk was volume concentrated to 2× in laboratory-scale stirred UF cells. Behavior of the organisms was analyzed in four inoculated milk samples: 2× retentate, 1× water-diluted retentate, milk equivalent (retentate plus permeate) and unconcentrated skim milk. Growth of each organism and of total aerobes did not vary in the four milk samples at either 7 or 13°C. For S. faecalis and E. coli, D-values for samples heated to 62.7°C did not significantly differ in the four milk samples (p&gt;0.01). The D-value of S. aureus in water-diluted retentate was slightly but significantly lower than those in the other three milk samples (p&lt;0.01), possibly due to the lowered lactose level in this sample.


2017 ◽  
Vol 35 (No. 4) ◽  
pp. 311-320 ◽  
Author(s):  
Abusheliabi Aisha ◽  
Al-Holy Murad A ◽  
Al-Rumaithi Hind ◽  
Al-Khaldi Sufian ◽  
Al-Nabulsi Anas A ◽  
...  

The growth behaviour of foodborne pathogens (Staphylococcus aureus, Listeria monocytogenes, E. coli O157:H7 and Salmonella spp.) was investigated in pasteurised camel milk and compared with pasteurised bovine milk at different incubation temperatures. This study also aimed to compare the growth patterns of these four foodborne pathogens in pasteurised and raw camel milk. Pasteurised or raw camel milk and pasteurised bovine milk were separately inoculated with a cocktail of three strains of each foodborne pathogen. The inoculated milk samples were incubated at 10, 25, and 37°C. The total bacterial count (TBC) in raw milk and the total thermoduric bacteria count (TDB) in pasteurised milk samples were monitored. Greater growth inhibition rates of four pathogens were obtained for the pasteurised camel milk compared to the pasteurised bovine milk. Raw and pasteurised camel milk exerted bacteriostatic effect against all tested pathogens, particularly for the first 8 h of incubation in milk at the different temperatures. Pasteurised camel milk exerted an inhibitory activity that was equivalent to that of raw camel milk.


2019 ◽  
Vol 49 (3) ◽  
pp. 407-417 ◽  
Author(s):  
Mohammad Yousefi ◽  
Maryam Farshidi ◽  
Mahmood Alizadeh Sani ◽  
Laleh Payahoo ◽  
Ali Ehsani

PurposeThis paper aims to evaluate the microbial quality of some traditional cheese samples (sheep, cow and koopeh cheeses) consumed in northwest of Iran, and to detect Shiga-like-toxin-producingEscherichia coli(STEC) and methicillin-resistantStaphylococcus aureus(MRSA) in cheese samples by polymerase chain reaction (PCR) method.Design/methodology/approachAlmost half of the project was based on counting the population of Staphylococcus aureus, total coliforms, Escherichia coli, and total aerobic mesophilic bacteria, also the other section was related to the isolation and the detection of the STEC and MRSA in cheese samples. The findings were compared with standard maximum and threshold values.FindingsThe results revealed that 36.99, 30.14 and 100% of cheeses exceeded the standard threshold value ofE. coli(102), total coliforms (104) andS. aureus(102). However, total coliforms, in any of the cheese samples examined, did not reach the maximum value and only 24.66% of samples exceeded the maximum value ofE. coli. Also, no significant difference (p> 0.05) in counts of each bacterial group examined in sheep, cow and koopeh cheeses was observed. The colony PCR method demonstrated the existence of 19 MRSA and 2 STEC isolates.Originality/valueThis research showed a general overview of the bacterial quality of cheeses in northwest of Iran.


2018 ◽  
Vol 12 (07) ◽  
pp. 533-541 ◽  
Author(s):  
Walid Elmonir ◽  
Etab Abo-Remela ◽  
Azza Sobeih

Introduction: Milk is an important food in Egypt and most of it is sold as raw milk in informal markets. Methodology: This study was conducted to investigate the public health risks of Escherichia coli and Staphylococcus aureus in milk sold in informal markets in Egypt. A total of 121 milk samples were analyzed for occurrence, virulence genes and antibiotic resistance of E. coli and S. aureus. Results: A total of 35/121 (28.9%) of milk samples were contaminated with 16/121 (13.2%) E. coli, 22/121 (18.2%) S. aureus, and 3/121 (2.5%) both isolates. Shiga-toxin producing E. coli (STEC), Enterotoxigenic E. coli (ETEC) and Enterotoxigenic S. aureus were detected in 5/121 (4.1%), 2/121 (1.7%) and 8/121 (6.6%) of the examined milk samples, respectively. Multiple drug resistances (MDRs) were showed by 14/16 (87.5%) and 21/22 (95.5%) of E. coli and S. aureus isolates, respectively. E. coli isolates showed high resistance for cephalothin (87.5%), ampicillin (68.8%) and tetracycline (68.8%), but were sensitive for gentamicin and chloramphenicol. Resistance phenotypes of E. coli were diverse; however, STEC isolates were significantly associated with co-resistance to cephalothin, ampicillin and tetracycline (P< 0.05). Two (9.1%) of S. aureus isolates were methicillin-resistant (MRSA) but sensitive to gentamicin (GS-MRSA). Five (22.7%) of S. aureus isolates were gentamicin-resistant methicillin-sensitive S. aureus (GR-MSSA). S. aureus isolates also showed high resistance for ampicillin (100%), tetracycline (90.1%) and sulfamethoxazole-trimethoprim (90.1%). Conclusion: These findings highlighted the potential public health hazards of E. coli and S. aureus pathogens in raw milk sold in informal markets in Egypt.


2018 ◽  
Vol 38 (7) ◽  
pp. 1358-1364 ◽  
Author(s):  
Gustavo P. Machado ◽  
Rodrigo C. Silva ◽  
Felipe F. Guimarães ◽  
Anelise Salina ◽  
Hélio Langoni

ABSTRACT: This study evalueted the prevalence of Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli in milk samples from 257 goats (513 half-udders) and ten bulk tanks, from ten dairy goat farms of São Paulo State, Brazil, by multiplex-PCR. The samples were screened by microbiological culture (gold-standard), and tested by different multiplex-PCR protocols for the detection of each bacterium. A total of 178 half-udders resulted positive by microbiological culture, with coagulase-negative staphylococci (70%), S. aureus (13.5%), S. intermedius (7.9%), and Enterobacteriaceae (4%) the prevalent pathogens. In other way, multiplex-PCR detected 173 pathogens in 151/523 (28.9%; CI95% 25.2-32.9%) milk samples 144/513 (28.1%) half-udders and 7/10 (70%) bulk tanks, with E. coli (86/162, 51.9%) and S. aureus (50/162, 30.9%) the prevalent ones in half-udders, and S. aureus (6/10, 60%) and E. coli (4/5, 36.4%) in bulk tanks. Multiplex-PCR showed a high performance for the detection of three bacteria at a time in mastitic goat milk direct from half-udders or bulk tanks. Thus, this multiplex-PCR protocol proved to be an adequate tool for the identification of the most common mastitis pathogens, independent of their phenotypic characteristics in the diagnosis of clinical mastitis in goats, allowing a continuous and better vigilance and monitoring the herd, being included in quality programs.


Author(s):  
Radhwane Saidi ◽  
Djamel Khelef ◽  
Rachid Kaidi

The present study was carried out to determine the prevalence of subclinical mastitis in cattle in eighteen herds in the center region of Algeria. Milk samples were collected from 560 quarters of 140 cows free of clinical mastitis. The samples were subjected to California Mastitis Test (CMT) and the positive samples were analysed by bacteriological culture and Speed ​​Mam® Color. The overall quarter prevalence was 28.77% whilst animal prevalence was 28.57%.Bacteriological analysis showed that there was a wide range of bacteria that cause these infections. Staphylococcus aureus (40%) was found to be the most prevalent organism followed by Streptococcus spp. (12.5%), Enterobacteriaceae (2.5%), Pseudomonas spp. (2.5%), Staphylococcusaureus + Streptococcus spp. (12.5%), Streptococcus spp.+ Escherichia coli (7.5%), S. aureus + Mycoplasma spp.(7.5%), and S. aureus +Streptococcus spp.+ E. coli (5%).


1997 ◽  
Vol 60 (10) ◽  
pp. 1174-1181 ◽  
Author(s):  
A. A. ADESIYUN ◽  
L. A. WEBB ◽  
H. ROMAIN ◽  
J. S. KAMINJOLO

The prevalence, counts, and characteristics of Escherichia coli isolated from bulk milk, composite milk, and feces of dairy cows in eight milking centers were determined. The microbial quality of water used during milking was also investigated. Of a total of 175 bulk milk samples studied, 83 (47.4%) contained E. coli compared to only 14 (4.9%) of 287 composite milk samples and the difference was statistically significant (P ≤ 0.001; χ2). The ranges in mean counts of E. coli per milliliter of bulk milk and composite milk were 8.4 × 103 to 2.0 × 105 and 2.1 × 101 to 2.0 × 102, respectively. The prevalences and mean counts of E. coli and mean pH values for bulk milk from farms with and without subclinically mastitic cows were not significantly different (P ≥ 0.05; χ2). A total of 204 (65.2%) of 313 fecal samples of dairy cows were positive for E. coli. Of the samples of water used during milking collected from 171 dairy farms, 80 (46.8%) were free of coliforms while 59 (34.5%), 12 (7.0%), and 8 (4.7%) had ranges of coliform counts per 100 ml of 1 to 50, 51 to 100, and over 250, respectively. Twenty-six (27.7%) and 17 (18.5%) of 94 strains of E. coli isolated from bulk milk were enteropathogenic E. coli (EPEC) and verocytotoxigenic E. coli (VTEC) strains, respectively. Compared with 204 fecal strains of E. coli, 16 (7.8%) and 68 (35.6%) were EPEC and VTEC strains, respectively, and the differences were statistically significant (P ≤ 0.01; χ2). Similarly, the difference in prevalence of resistance to one or more of nine antimicrobial agents between bulk milk isolates (69.6%) and fecal isolates (25.9%) was statistically significant (P ≤ 0.001; χ2), and resistance to ampicillin was the most prevalent type of resistance for strains of E. coli from bulk milk isolates. It was concluded that the relatively high counts of toxigenic E. coli in bulk milk originating from dairy farms in Trinidad could pose a health risk to consumers. The poor microbial quality of water used on farms may be an important source of contamination of milk.


2017 ◽  
Vol 35 (1) ◽  
pp. 63
Author(s):  
Herwin Pisestyani ◽  
Etih Sudarnika ◽  
Rachmi Ramadhanita ◽  
Abdul Zahid Ilyas ◽  
Chaerul Basri ◽  
...  

Mastitis is udder inflammation that can be caused by the entry of pathogenic bacteria through the teat. One of the treatments that can prevent bacteria infection is teat dipping. This research was aimed to identify the effectof teat dipping after milking to the presence of pathogenic bacteria that cause subclinical mastitis (Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli) and the presence of pathogenic bacteria that cause subclinicalmastitis by quarter of udder. Milk samples were taken from normal lactation period of dairy cows, clinically healthy, and positive subclinical mastitis status when the intervention was applied. Sixty seven samples of quarters from 18dairy cows were identified to the presence of pathogenic bacteria that cause subclinical mastitis before teat dipping and at 1st, 2nd, and 3rd months after teat dipping. Identification of the presence of pathogenic bacteria was done byculturing samples on selective agar media. The presence of common pathogenic bacteria, Staphylococcus aureus, and Escherichia coli decreased significantly after teat dipping, while Streptococcus agalactiae and other pathogenicbacteria did not decrease significantly. The presence of pathogenic bacteria based on the quarter of udder did not show the significance difference. Application of teat dipping after milking was able to decrease the presence ofpathogenic bacteria that cause subclinical mastitis.


2018 ◽  
Vol 41 (4) ◽  
pp. 353-363
Author(s):  
Alberto J. Valencia-Botin ◽  
Melesio Gutiérrez-Lomelí ◽  
Juan A. Morales-Del-Río ◽  
Pedro J. Guerrero-Medina ◽  
Miguel A. Robles-García ◽  
...  

Actualmente existe la necesidad de hacer frente al problema de la resistencia a los antibióticos y al uso indiscriminado de fungicidas químicos en la agricultura. El objetivo de este trabajo fue evaluar el efecto inhibitorio de extractos acuosos, metanólicos, acetónicos y hexánicos de hoja y tallo de Vitex mollis Kunth (Lamiaceae) contra diferentes bacterias (Escherichia coli, Micrococcus luteus, Salmonella enterica y Staphylococcus aureus) y especies del hongo Fusarium (F. verticillioides, F. oxysporum, F. tapsinum y F. oxysporum f.sp. lycopersici) de importancia en la salud y en la agricultura, así como determinar su composición química general. Se determinaron las concentraciones inhibitorias mínimas (CIM) de todos los extractos por la técnica de microdilución, excepto del hexánico, que no presentó inhibición en las bacterias estudiadas. S. enterica fue la bacteria que mostró mayor sensibilidad al extracto metanólico de tallo (CIM = 28 μg mL-1), le siguieron M. luteus (CIM = 32 μg mL-1), S. aureus (CIM = 75 μg mL-1) y E. coli (CIM = 80 μg mL- 1). Los extractos metanólicos y acuosos de tallo presentaron mayor porcentaje de inhibición contra los diferentes tipos de Fusarium evaluados por el método de dilución en agar. Los extractos de V. mollis inhibieron a F. verticillioides entre 62 y 91 % con 120 μg mL-1 de extracto. El orden de las especies de hongos inhibidas por los extractos fue: F. verticillioides > F. oxysporum > F. tapsinum > F. oxysporum f.sp. lycopersici. La composición química de las especies se determinó mediante pruebas para fenoles, taninos, flavonoides, triterpenos, alcaloides, cumarinas y saponinas. Ninguno de los extractos presentó alcaloides y saponinas. Los fenoles (37.1 mg EAG/g muestra seca) y flavonoides (26.8 mg EQ/g muestra seca) fueron los compuestos mayoritarios en los extractos metanólicos y acuosos. En conclusión, se requieren cantidades muy pequeñas de extracto para la inhibición de bacterias y de Fusarium; por lo tanto, V. mollis puede ser considerada una fuente de metabolitos para este fin y en la agricultura como control alternativo dentro de un manejo integrado de enfermedades.


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