Antimicrobial Susceptibility Pattern of Enteric Bacteria from Fresh cow milk and handlers in Zaria Metropolis, Kaduna State Nigeria

AROC in Pharmaceutical and Biotechnology, 2021, 1(2);35-42

Abstract

A bacteriological examination of raw cow milk for the isolation of enteric based bacteria was conducted on milking cows and their handlers from selected farms in four Local Governments in Zaria, Kaduna State. The aim of the study was to check the quality of the raw cow’s milk and also verify the rate of contaminations of the raw cow’s milk from external sources which are regarded as environmental pathogens during and after milking processes. A total of 105 samples; 42 raw milks from lactating cows, 42 swabs from cow teat, 16 swabs from herd handlers and 5 samples from water used in the cleaning process were obtained. The raw milk samples were screened using a Methylene dye reagent to check its microbial load before analysis began, the total bacteria count (TBC) and total coliform count (TCC) were analyzed using the standard cultural methods. The isolates were identified using the standard biochemical procedure and Microgen TM System (GN-ID A+B Kit). Results revealed that one hundred and two (102) bacteria consisting of Seventy-six (76) Polymicrobial and twenty-six (26) single cultures were recovered as positive culture while three (3) had no growth. The mean TBC and TCC of raw milk observed in this study were 2.56 ± 0.40 x104cfu/ml and 1.06 ± 0.16 x104cfu/ml respectively. Acinetobacter iwoffi and other members of Enterobacteriaceae isolates were resistant to tetracycline (68.75%), erythromycin (71.74%) and metronidazole (100%), while high susceptibility was observed to gentamicin (94.34%) and chloramphenicol (80.85%). High bacterial contaminations including Multidrug-resistant bacteria were observed in this study, contaminations were majorly from improper pre and post dipping processes and the use of non-portable water.

Corresponding Author(s)

Bilikis Abimbola Olunrebi Email: bimm26@gmail.com Mobile: +234 703 282 7225

Citations

Olunrebi, B.A., Onaolapo, J.A., Bolaji, R.O., and Otaru, S. (2021). Antimicrobial Susceptibility Pattern of Enteric Bacteria from Fresh cow milk and handlers in Zaria Metropolis, Kaduna State Nigeria. AROC in Pharmaceutical and Biotechnology, 1(2);35-42, https://doi.org/10.53858/arocpb01023542

1.0 Introduction

Milk is an aqueous colloidal suspension of protein, fats, carbohydrates and it contains numerous vitamins and minerals [1]. Raw milk is milk from any animal that has not been pasteurized or homogenized [2]. Raw milk essentially comes from a sterile environment within the animal, the risk of contamination begins within the udder, skin, faeces, milking equipment, handling and storage [3,4]. Improper cleaning and sanitizing of the cow’s udder is one of the major sources of high-level bacteria count in raw milk. In a study conducted in Santa Catarina, it was reported that the udder cleaning process was performed incorrectly, reinforcing the need for offering continuous training focused on showing dairy farmers how important is to sanitize the udders of the cows in order to have raw milk with low bacterial count [5]. The high amounts of bacteria found in refrigerated raw milk can be explained by the fact that in small farms there are several hygiene problems occurring during milking and raw milk storing processes [6,7].

Coliform bacteria are normal inhabitants of soil, digestive tract and manure and they accumulate and multiply in contaminated bedding. Detection of coliforms plays an important role in the dairy industry because coliforms are frequently used as hygiene indicators and there are clear regulatory limits for the presence of coliforms in finished dairy products. For example, the US Pasteurized Milk Ordinance limits the number of coliforms in pasteurized grade “A” milk to ≤10 CFU/ mL [8]. Coliform numbers of 1,000,000 or more per gram of bedding increase the likelihood of an udder infection and clinical mastitis [9]. Mastitis caused by coliform is a cause of concern, the infection is usually confined to one or two-quarters of the udder and the infection occurs very fast. Cows may appear healthy during a milking process and they could be sick during the next milking session. The raw milk from the sick cow usually appears watery or yellowish and contain flakes or clots. Escherichia coli, a major inhabitant of the intestines of all animals is mostly associated with coliform mastitis, when this enteric organism is allowed to spread unchecked because of unhygienic practices during the milking process and dirty environmental factors, these could lead to serious problems and threats to the dairy chain [10].

The presence of coliform organisms in milk has been linked to a wide variety of human infections such as endocarditis, urinary and genital tract infections, meningitis and septicemia [11.] In this regard, similar studies related to ensuring raw milk safety need to be carried out in order to provide reliable information which can improve the quality of milk.

2.0 Materials and Methods

2.1 Study design
A cross-sectional study was carried out on raw cow milk supplied to the community for consumption and/or processing into other milk products. The study aimed at monitoring the rate of contamination of the raw milk samples, therefore, swab samples were taken from the cow teat and the handlers as well as some quantity of water used in the cleaning process on the farm. A total of 105 samples were collected for this study (Table 1). The selection of farms was based on; different management conditions, the willingness of the farmers/pastoralists to participate in the study, and accessibility of the location, so that samples collected could be immediately transferred to the laboratory for further analysis.

2.2 Sample collection
Sampling was performed according to the International Dairy Federation guidelines [12]. Individual cows were properly restrained and the teats were washed and disinfected using a disposable paper towel immersed in a pre-dip iodine solution; in a concentration of one in ten milliliters (1:10) of iodine and water. This process of pre-dipping was performed by the herd handlers and then a sterile swab stick was used to clean the udder. The first stream of milk was allowed to run off, thereafter, sample of raw milk was collected in sterile universal bottles and sealed air tight. Containers were marked with source of sample, the date and time of sampling and other relevant information. Also, sterile swab sticks were used to take samples from the handler and sample of the water used on the farm for cleaning were taken. After collection, the samples of raw milk were carried in ice box maintaining at a temperature of 4 – 50 C and brought to the laboratory, preserved in refrigerators within 1 hour until analysis begin.

Table 1: The Sampling data analysis

FarmRaw cow milkSwab from teatSwab from handlerWaterTotal (%)
Zango    0404020111 (10.48)
Jamaa Lima0404020111 (10.48)
Kufenia0303020109 (8.57)
NAPRI3231100274 (70.47)
 42421605105 (100)

2.3 Media Preparation
All glassware including petri dishes, test tubes and pipettes used in this analysis were sterilized using a hot oven at 180 ± 50C for at least 1 hour. Each bacteriological medium was prepared from commercially available powder according to the Manufacturer’s instructions and sterilized by autoclaving at 121°C for 15 minutes.

2.4 Isolation and Identification
Tenfold serial dilutions of samples of raw cow milk were carried out in peptone water, then one hundred microliter (0.1 ml) of 1:103 and 1:104 dilutions were plated out using surface plating technique on Nutrient Agar (NA) for total aerobic bacteria count (TBC) and MacConkey agar (MAC) for total coliform count (TCC) present in the raw milk sample. The inoculated plates were then inverted and incubated at 37°C for 24 hours. Thereafter, the plates were screened for the presence of discrete colonies and for each dilution, visible colonies that appeared were counted and the average were estimated as colony forming unit in per ml (cfu/ml).

Individual pinkish colonies on MacConkey agar were picked and sub cultured onto freshly prepared MacConkey agar plate to confirm the cultural and morphological characteristics of the coliform isolate. Samples of teat swab, swab from handler and water used on farm were also cultured onto freshly prepared MacConkey medium, the cultured plates were incubated at 37°C for 24 h. Representative colonies were stored in slant bottles containing freshly prepared nutrient agar and kept in the refrigerator (4°C) until required for further work.

2.5 Biochemical tests for Coliforms
Conventional biochemical tests as reported by Cheesebrough [13], which include Catalase, Oxidase and Methyl red voges-proskauer (MRVP). They were done to preliminarily identify the bacteria isolates before using a commercial kit for Enterobacteriaceae (Medica-TecTM Microgen GN-ID A+B Kit) to confirm the isolates to the specie level.

2.6 Antimicrobial Sensitivity Testing
Antimicrobial sensitivity was carried out on the coliform isolates using commercially prepared antimicrobials (Oxoid). Selected antibiotics used in this study are those commonly prescribed by doctors for food borne infections in Zaria metropolis. These include: Amoxicillin- clavulanic acid (AMC; 30 μg), Ampicillin (AMP; 10 μg), Ceftazidime (CAZ; 10 μg), Ciprofloxacin (CIP; 5 μg), Gentamicin (CN; 10μg), Tetracycline (TET; 30 μg), Chloramphenicol (CHL; 30 μg), Erythromycin (ERY; 15μg) and Metronidazole (MTZ; 10 μg)

Discrete colony of isolates on nutrient agar plates were emulsified in 5 mL sterile physiological saline and turbidity adjusted to 0.5 McFarland standard (approximately a cell density 1.5 x 108 cfu/mL) using the modified Kirby-Bauer method. The standardized suspension was inoculated on prepared Mueller-Hinton agar using sterile cotton swab stick to ensure an even distribution and confluent growth of the isolate. After inoculation, plates were allowed to dry before placing the antimicrobial disks aseptically using sterile forceps. The plates were incubated at 37 °C for 24 hours after which the zone of inhibition was measured in millimeters (mm) and compared against a reference standard and interpreted according to Clinical and Laboratory Standard Institute [14]

2.7 Data Analysis       
The Statistical Package for Social Science (SPSS) version 20 was used to analyze the data. The result of sensitivity to tested antimicrobials were compiled in tabular forms.

3.0 Result and Discussion

The raw cow milk samples appeared fresh, creamy to whitish color with no curd formation observed. The pH readings of the sample milk were between 6.6-6.8 which were within the normal range of standard grade ‘A’. Sixty (60) bacteria species which are members of enterobacteriacea were isolated from this study with a prevalence rate of 35.5%. Other bacteria species isolated include Micrococcus luteus, some group of Staphylococcus species. The mean total bacteria count (TBC) and total coliform count (TCC) observed in this study was 2.56±0.40×104 cfu/mL and 1.06±0.16×104 cfu/mL respectively (Table 2).

Table 2: Mean Total Viable Count of Isolates from Fresh raw cow milk

FarmTBC (x104cfu/ml)TCC (x104cfu/ml)
Zango1.13±0.640.58±0.70
Sabo2.43±1.570.98±0.83                                 
Kufenia0.8±0.790.87±0.49
NAPRI2.93±2.881.16±1.1
Overall Mean2.56±0.40                  1.06±0.16

Key: TBC: Total Bacteria count, TCC; Total Coliform count

The prevalence observed in this study is relatively high when compared with report of a prevalence of 10.3% in Kaduna Nigeria [15], but considerably lower when compared with 52% reports in Sokoto Nigeria, and 61.1% in Ethiopia [16, 17]. The TBC and TCC observed in this study are relatively high when compared to the standard limits given by Food and Drug Association (FDA) pasteurized milk ordinance for grade A use [8] of ˂10- 105cfu/mL for total viable bacteria count and ≤ 10 cfu/mL for coliform count respectively. The result obtained in this study is however lower when compared with report of TBC and TEC of 0.2- 4.2×106 CFU/mL and 0.8- 2.6×106 CFU/mL respectively in Ogbomosho Nigeria [18].

3.1 Bacteria Isolates from Farm

Raw milk sampled from Zango and Jamaa lima farms have higher numbers of Staphylococci species (Table 3). Proteus vulgaris were the most recovered isolates from milk sampled from Kufenia farm and was also recovered from cow teat and handler swabs (Table 3).  Raw milk sampled from NAPRI has higher numbers of occurrence of Acinetobacter iwoffi among the Enteriobactericea isolates and higher numbers of occurrence of Staphylococci species among the Gram-positive isolates (Table 3). A. iwoffi was also recovered from cow teat and handler swabs (Table 3).

Table 3: Bacteria Isolation Pattern from Farm

FarmOrganismSourceTotal (%)
MilkTeatHandlerWater
ZangoAcinetobacter iwoffi010102 (40)
 Klebsiella pneumoniae0101 (20)
 Pasteurella multocida01 –01 (20)
 Providencia stuartii0101 (20)
   TOTAL0102010105 (100)
SaboCitrobacter youngae0101 (16.7)
 Escherichia coli0101 (16.7)
 Flavobacterium odoratum0101 (16.7)
 Klebsiella oxytoca0101 (16.7)
 Pseudomonas aeruginosa010102 (33.3)
       TOTAL0102020106 (100.1)
Kufenia      
 Acinetobacter iwoffi0101 (10)
 Aeromonas caviae0101 (10)
 Citrobacter freundi0101 (10)
 Escherichia coli  0101 (10)
 Proteus vulgaris02020105 (50)
 Yersinia enterocolitica0101 (10)
      TOTAL0403020110 (100)
Giwa      
 Acinetobacter iwoffi08030112 (30.8)
 Aeromonas hydrophila0303 (7.7)
 Burkholderia pseudomallei0101 (2.6)
 Escherichia coli0101 (2.6)
 Hafnia alvei010102 (5.1)
 Moraxella specie0401010107 (17.9)
 Pantoea agglomerans020103 (7.7)
 Plesiomonas shigelloides0101 (2.6)
 Proteus mirabilis0101 (2.6)
 Proteus vulgaris 010102 (5.1)
 Providencia stuartii 0101 (2.6)
 Pseudomonas aeruginosa0202 (5.1)
 S. choleraesus  01 (2.6)
 Vibrio parahaemolyticus0101 (2.6)
 Weeksela zoohelcum 0101 (2.6)
       TOTAL2408060139 (100.2)

Isolation of E. coli, Klebsiella specie, Proteus specie and Enterobacter specie from fresh cow milk in Sokoto Nigeria [16], this report is in close agreement with the findings from this study. Also, in a cross-sectional study carried out in Gondar town, Ethiopia identified 54 different bacterial species, and they include E. coli, Pseudomonas aeruginosa and Klebsiella pneumoniae as the most commonly identified gram-negative staining bacterial pathogens which is similar to the findings from this study [17].

In addition, majority of coliform isolates from a study conducted using the raw milk consumed in Khartoum, Sudan were E. coli, Enterobacter specie, Klebsiella specie, Serratia specie and Citrobacter [19], which closely agree to the findings from this study.

3.2 Antimicrobial Resistance observed among the Enterobacteriaceae
The antimicrobial resistance pattern observed among the identified Enterobacteriaceae species were Amoxicillin- Clauvulanic (67.31%), Tetracycline (68.75%), Erythromycin (71.74%), Ceftazidime (88.68%) and Metronidazole (96%) which is in close agreement to antimicrobial resistance of tetracycline and erythromycin reported in Kaduna, Nigeria [15], and resistance to erythromycin (85.71%) reported in Zaria, Nigeria [20]. Susceptibility was highly shown to Gentamicin (94.34%), Chloramphenicol (80.85%), and Ciprofloxacin (77.08%) among the identified Enterobacteriacea in this study (Table 4), which is similar to Gentamicin and Ciprofloxacin (100%), Chloramphenicol (93%) reported in Zaria, Nigeria [20] and also similar to reports of susceptibility to both gentamicin and Ciprofloxacin in all the tested isolates of coliform from raw milk in Ogbomosho, Nigeria [18].

Table 5 shows the pattern of resistance exhibited in the present study, this may be due to prolonged and indiscriminate usage and prescription of related antibiotics which often leads to possible resistance development in animals [21,22].

Table 4: In-vitro Sensitivity testing of bacterial isolates to nine antimicrobials.

Drug Class          Antimicrobialscontent (ug)NResistance (%)   Susceptible(%)
CephalosporinsCeftazidime105347(88.68)6(11.32)
TetracyclineTetracycline304833(68.75)15(31.25)
FluoroquinolonesCi[profloxacin54811(22.92)37(77.08)
PenicillinAmoxi-Clavulanic305235(67.31)17(32.69)
PenicillinAmpicillin103619(52.78)17(47.22)
AminoglycosidesGentamicin10533(5.66)50(94.34)
MacrolidesErythromycin154633(71.74)13(28.26)
PhenicolsChloramphenicol30479(19.15)38(80.85)
Nitro imidazoleMetronidazole105252(100)

key: N indicates number of tested Isolates; % Resistance indicates calculated resistant isolates; % Susceptibility indicates calculated susceptible isolates

Table 5: Antibiotic Resistance Pattern of Enterobacteriaceae isolates

S/NBacteria isolates  Antibiotic Resistance (%)
CAZTETCIPAMPCNERYAMCCHLMTZ
 Acinetobacter iwoffii (n=14)85.735.77.142.97.142.978.614.3100
 Aeromonas hydrophila (n=03)10033.3066.7010010033.3100
 Burkholderia pseudomallei (n=01)010010001001000100
 Citrobacter freundi (n=01)100000010000100
 Citrobacter youngae (n=01)1001001001001001001000100
 Escherichia coli (n=02)100005000500100
 Hafnia alvei (n=02)05050005050050
 Klebsiella oxytoca (n=01)100100010001001000100
 Klebsiella pneumoniae (n=01)1000010001001000100
 Moraxella specie (n=06)10010005016.733.35016.7100
 Pantoea agglomerans (n=03)33.366.700066.733.3066.7
 Pasteurella multocida (n=01)10010001000100100100100
 Plesiomonas shigelloides (n=01)100001000100100100100
 Proteus  vulgaris (n=07)10071.457.142.9085.742.90100
 Proteus mirabilis (n=01)1001000100010000100
 Providencia stuarti (n=02)10050505005000100
 Pseudomonas aeruginosa (n=03)10010033.366.7010010066.7100
 S. choleraesus100100010000100100100
 Vibrio parahaemolyticus1001000100001000100
 Weeksela zoohelcum1000000000100
 Yersinia enterolitica100100100100 1001000100

CAZ = Ceftazidime, AMP = Ampicillin, AMC = Amoxicillin Clavulanic acid, TET = Tetracycline, CN = Gentamicin, CHL = Chloramphenicol, CIP = Ciprofloxacin, ERY = Erythromycin, MTZ= Metronidazole

Overall, 53.8% of the isolates were multidrug-resistant. There was no significant association between sample source and multi-resistance phenotype, however, isolates from teat swabs were more likely to be non-multidrug resistant (p= 0.555). There was no significant association between sampling location and multi-resistance phenotype, however, isolates from Zango farm were more likely to be non-multidrug resistant compared to strains from Sabo farm, most of which were extensively drug-resistant (p= 0.145).

Acinetobacter iwoffii isolates were multidrug-resistant, while Pseudomonas aeruginosa were extensively drug-resistant (Table 6).  In this study, the percentage of multiple antibiotic resistance index (MARI) of greater than or equal to 0.3 was observed to be; 92% for Enterobacteriaceae (Table 7).

Table 6: Multidrug Resistance Classification of Enterobacteriaceae isolates

S/NBacteria isolates  (%)
PDRXDRMDRnMDR
 Acinetobacter iwoffii (n=14)021.471.47.1
 Aeromonas hydrophila (n=03)066.733.30
 Burkholderia pseudomallei (n=01)001000
 Citrobacter freundi (n=01)001000
 Citrobacter youngae (n=01)010000
 Escherichia coli (n=02)005050
 Hafnia alvei (n=02)005050
 Klebsiella oxytoca (n=01)010000
 Klebsiella pneumoniae (n=01)001000
 Moraxella specie (n=06)033.366.70
 Pantoea agglomerans (n=03)0066.733.3
 Pasteurella multocida (n=01)010000
 Plesiomonas shigelloides (n=01)010000
 Proteus  vulgaris (n=07)042.957.10
 Proteus mirabilis (n=01)001000
 Providencia stuarti (n=02)050050
 Pseudomonas aeruginosa (n=03)010000
 S. choleraesus010000
 Vibrio parahaemolyticus001000
 Weeksela zoohelcum000100
 Yersinia enterolitica010000

Table 7: Multiple Antibiotic Resistance Index (MARI) of Enterobacteriaceae isolates

MARIDistributionPercentage (%) 
0.2048 
0.30816      92%
0.40510
0.5048
0.61122
0.70714
0.80816
0.9036
 50  

There are several improper sanitary checks done on the farm which could have resulted in contamination of the raw milk. These include; Unavailability of good portable water used on the farms; and improper udder preparations by inadequate washing and disinfecting with detergent; and improper pre-and post- dipping solutions; and improper periodic handwashing by the handlers, these are reasonable means of introducing contaminations directly into the raw milk. The report in this study revealed on the average low level of education and awareness among small scale dairy farm handlers on a need to maintain adequate hygiene levels during milking practices. Therefore, regulatory bodies are summoned to ensure periodic assessment and reinforcing measures to educate and monitor the dairy value chain practices in areas of concern.  Importantly, the populace needs to be readily informed and/ or reminded about the risk and dangers of consuming raw milk irrespective of their cultural beliefs, as well as educated on the need to pasteurize the raw milk before consumption.

4.0 Conclusion

The majority of the farm owners and handlers do not observe pre-dipping and post-dipping cleaning processes or it is performed incorrectly, which could have resulted in high bacterial contaminations including Multidrug-resistant bacteria observed in this study. Additionally, the analysis on the water used on four farms visited in this study showed the presence of high bacterial load, especially members of the Enterobacteriaceae, all these could be the leading source of contamination of the raw cow milk.

Authors Contributions: The work was conducted and reviewed in collaboration of all authors. All authors have read and agreed to the published version of the Manuscript.

Funding: This work received no external funding.

Institutional Consent Statement: Not Applicable

Acknowledgements: Not Applicable

Conflict of Interest: The authors declare that no conflict of interest exists.

Ethical Consideration: Ahmadu Bello University ABU Committee for Use of Animal Subjects for Research (ABUCUHSR) and Ethical Committee of National Animal Production Research Institute (NAPRI) Shika, Zaria.

REFERENCES

1         Ogbolu D.O., Terry-Alli A.O., Oluremi A.S. and Olanrewaju A.A. (2014). Microbial contamination of locally produced cheese and determination of their antimicrobial potential in Nigeria. African Journal of Clinical and Experimental Microbiology 15(2): 76-83.

2         Centers for Disease Control and Prevention (2012).ttps://www.cdc.gov/features/rawmilk/index.html

3         John A. Lucky, (2015). Raw Milk Consumption; Risks and Benefits. Nutrition Today. 50 (4):189-193.

4         Cancino-Padilla N., Fellenberg M A.,Franco W., Ibanez R A. and Vargas-Bello-Perz E. (2017). Foodborne bacteria in dairy Products: Detection by molecular techniques.Ciencia Investigation Agraria:  8:215-229

5         Maldaner, N., Diane S., Debora O. and Eliandra M. (2012). Evaluation of Microbiological Quality of Raw Milk Produced at Two Properties in the Far West of Santa Catarina, Brasil. Food and Public Health, 2, 79-84

6         Mhone, T. A.; Matope, G. and Saidi, P. T. (2011). Aerobic bacterial, coliform, Escherichia coli and Staphylococcus aureus counts of raw and processed milk from selected smallholder dairy farms of Zimbabwe. International Journal of Food Microbiology, 151, 223–228.

7         Suranindyah, Y., Wahyuni E., Bintara S., and Purbaya G. (2015). The effect of improving sanitation prior to milking on milk quality of dairy cow in farmer group. Procedia Food Science, 3, 150-155.

8         FDA. 2011. Standards for grade “A” milk and milk products. Pages 27–30 in Grade “A” Pasteurized Milk Ordinance. Standards for grade “A” milk and milk products. US Department of Health and Human Services, Public Health Service, Washington, DC.

9         Podder MP, Rogers L, Daley PK, Keefe GP, Whitney HG, Tahlan K (2014). Klebsiella species Associated with Bovine Mastitis in Newfoundland. PLoS ONE 9(9):106518.

10       Raghvendra Kumar Mishra, Rajesh Singh Tomar and Monika Gupta (2017). International Journal Pharmaceutical Biological Science; 8(3):(B) 100-104.

11       Centers for Disease Control and Prevention (2015). https://www.cdc.gov/foodsafety/rawmilk/rawmilk-index.html

12       International Dairy Federation (IDF. 1995). Milk and milk product- guidance on sampling, IDF Standard 50C. Brussels, Belgium: International Dairy Federation.

13       Cheesbrough, M. (2006). District Laboratory Practice in Tropical Countries. Part 2. Low Price Edition. Cambridge University Press, London.

14        Clinical and Laboratory Standard Institute (CLSI) (2018). Performance Standards for antimicrobial susceptibility testing. 26th edition. CLSI document M100-S26. Wayne, PA

15       Mbuk E. U., Kwaga J.K.P., Bale J.O.O., Boro L.A. and Umoh J.U., (2016). Coliform organisms associated with milk of cows with mastitis and their sensitivity to commonly available antimicrobials in Kaduna. Nigeria. Journal of Veterinary Medcine and Animal Health. 8(12): 228-236.

16       Junaidu A.U., Salihu M.D., Tambuwala F.M., Magaji A.A. and Jaafaru S. (2011). Prevalence of mastitis in lactating cows in some selected commercial dairy farms in Sokoto Metropilis. Pelagia Advance of Applied Science Research 2(2: 290-294.

17       Garedew L, Berhanu A, Mengesha D, Tsegay G (2012). Identification of gram-negative bacteria from critical control points of raw and pasteurized cow milk consumed at Gondar town and its suburbs, Ethiopia. BMC Public Health pp.12-950.

18       Oladipo I.C., Tona G.O, Akinlabi E.E and Bosede O.E (2016). Bacteriological quality of raw cow’s milk from different dairy farms in Ogbomosho Nigeria. International Journal of Advanced Research in Biological sciences; 3(8): 1-6.

19       Salman AMA, Hamad IM (2011). Enumeration and identification of coliform bacteria from raw milk in Khartoum State, Sudan. Journal of Cell Animal Biology 5(7):121-128.

20       Tamba Z., Bello M. and Raji M.A. (2016). Occurrence and Antibiogram of Salmonella specie in Raw and Fermented Milk in Zaria and Environs. Bangledash Journal of Veterinary Medicine. 14(1): 103-107.

21       Kwaga JKP (2012). Veterinary intervention on the global challenge of antimicrobial resistance. Paper presented at the World Veterinary Day Celebration, 28th April, 2012. NVMA, Kaduna.

22       Sharma M, Dogra BB, Misra R, Gandham N, Sardar M, Jadhav S (2014). Multidrug resistant Pantoea agglomerans in a patient with septic arthritis-a rare report from India. International Journal of Microbiology Research. 4:263-265.

Recent Journals

Newsletter subscription

Get an alert in your inbox when we upload new journals