Bacteriological Quality of Raw Cow Milk in Shahrekord, Iran Seasons Region Sample No. of Positive Sample (%)

Introduction C. jejuni [6], E. coli, coliforms, S. aureus [4]. The quality and safety of raw milk can be evaluated by Milk and other dairy products from cows, goats, assessing hygiene indicator microorganisms. Total and sheep are important components of the people diet. coliform, E. coli and S. aureus are used as hygienic Milk do have distinct physical, chemical and biological parameters for milk production, as they indicate the characteristics and its colour, odour, taste, consistency, conditions of raw milk obtaining and storage, and freezing point (-0.55°C), pH (6.6) and specific gravity inadequate handling during the manufacturing process. (1,032) are characteristics that remain particularly These microorganisms are usually associated with constant [1]. The bacterial contamination of milk not food borne diseases and outbreaks, as recorded by only reduces the nutritional quality but also official health organizations [7]. consumption of such milk threatens health of the The presence of these pathogenic bacteria in milk society [2]. Milk is also an excellent medium for the appeared as main public health concerns, especially for growth of different microorganisms, which may cause those people who still drink raw milk [8]. It therefore various food borne diseases. became the aim of the study to determine the presence The disease causing bacteria in the milk are of contaminating microorganisms in the milk Salmonella spp., Mycobacterium bovis, Corynebacterium produced by small scale dairy farmers in a typical in spp. Materials and Methods spp., Escherichia coli, and coliforms. Many bacteria could get an easy access to milk and milk products such Samples: A total of 300 samples of raw milk (milk as E. coli and coliforms; they are often used as indicator collection station) were collected from different places organisms to confirm the bacterial contamination of (Northeast , East, Southeast, South, and Southwest) of milk. Most common pathogens that have been Shahrekord city. At each location, samples of involved in milk borne diseases include Salmonella approximately 300 ml milk were taken aseptically spp., Staphylococcus aureus, and E. coli. In recent from the bulk milk container into sterile glass bottles. years, there are several studies related to raw milk Procedure: According to the recommended procedures contamination including: infection with C. jejuni, (pour plate method) colony counting of the bacteria Listeria monocytogenes, and E. coli strain O157 [3, 4], was done. The Eosine Methylene Blue (EMB) and Campylobacter spp., Salmonella spp. and E. coli [5], blood agar media were inoculated …


Introduction
C. jejuni [6], E. coli, coliforms, S. aureus [4].The quality and safety of raw milk can be evaluated by Milk and other dairy products from cows, goats, assessing hygiene indicator microorganisms.Total and sheep are important components of the people diet.
coliform, E. coli and S. aureus are used as hygienic Milk do have distinct physical, chemical and biological parameters for milk production, as they indicate the characteristics and its colour, odour, taste, consistency, conditions of raw milk obtaining and storage, and freezing point (-0.55°C),pH (6.6) and specific gravity inadequate handling during the manufacturing process.(1,032) are characteristics that remain particularly These microorganisms are usually associated with constant [1].The bacterial contamination of milk not food borne diseases and outbreaks, as recorded by only reduces the nutritional quality but also official health organizations [7].consumption of such milk threatens health of the The presence of these pathogenic bacteria in milk society [2].Milk is also an excellent medium for the appeared as main public health concerns, especially for growth of different microorganisms, which may cause those people who still drink raw milk [8].It therefore various food borne diseases.
became the aim of the study to determine the presence The disease causing bacteria in the milk are of contaminating micro-organisms in the milk Salmonella spp., Mycobacterium bovis, Corynebacterium produced by small scale dairy farmers in a typical in spp., Clostridium perfringens, Yersinia enterocolitica, Shahrekord, Southwest Iran South area where milking Coxiella burnetii, Brucella, Staphylococcus, is done by hand.

spp., Escherichia coli, and coliforms. Many bacteria could get an easy access to milk and milk products such
Samples: A total of 300 samples of raw milk (milk as E. coli and coliforms; they are often used as indicator collection station) were collected from different places organisms to confirm the bacterial contamination of (North-east, East, Southeast, South, and South-west) of milk.Most common pathogens that have been Shahrekord city.At each location, samples of involved in milk borne diseases include Salmonella approximately 300 ml milk were taken aseptically spp., Staphylococcus aureus, and E. coli.In recent from the bulk milk container into sterile glass bottles.years, there are several studies related to raw milk Procedure: According to the recommended procedures contamination including: infection with C. jejuni, (pour plate method) colony counting of the bacteria Listeria monocytogenes, and E. coli strain O157 [3,4], was done.The Eosine Methylene Blue (EMB) and Campylobacter spp., Salmonella spp.and E. coli [5], blood agar media were inoculated and kept at 37 °C for 24-48 hours.For identification of coliforms, and E. coli, the differential media, such as TSI, urea, and Simmon citrate were inoculated.For the isolation and identification of E. coli, the enriched sample was 47%, whereas Streptococcus and E. coli in 32% and 21%of the samples respectively [11].Another report cultured on selective medium Levine Eosin Methylene revealed that out of 135 samples, 25 samples were Blue (EMB) Agar and incubated at 37ºC for 24 h.
found to be contaminated with Staphylococcus 14 and Morphologically, typical colonies (at least 4/plate) E.coli 11 [12].Report on contamination of the raw milk producing metallic sheen were taken into nutrient broth samples in Malayer city of Iran was as follow: E. coli for further identification.Biochemical tests were 75%, Enterobacter 42%, Klebsiella 36% and S. aureus performed to confirm E. coli using Gram staining, 52% [13].(96.66%) and19 (63.33%), respectively.Indeed, they coagulase test, were performed too.The colonies were were more than those prepared in winter with counted using colony counter and the number was coliforms, E. coli, and S. aureus with 26 (86.66%), 25 recorded as colony forming unit/ml (CFU).For testing, (83.33%) and 18 (60%), respectively (p<0.05).In 5 dilutions of milk samples, 1, 0.1, 0.01, 0.001 and Nowary and Italay 55%,43% samples of cow milk 0.0001 ml were used.Aseptically, 1 ml of milk was contaminated with S. aureus, respectively [14,15].In added to the sterile test tube containing 9 ml of sterile Malaysia, Thaker and colleagues [16] indicated that distilled water, mixed properly by cyclometer, 15 ml of 90% of the examined raw milk were contaminated by medium was poured in the plate containing 0.1 ml of coliform bacteria and 65% were E. coli.When the sample and shake to mix thoroughly and uniformly number of isolates in the raw milk are compared in two with the agar medium.The agar was allowed to be seasons of the year, it is noticed that numbers of the solidified and the petri-dishes were incubated at 37°C detected organisms in the summer is higher than the for 48 hours.A negative control was prepared using winter season.The reason could be that in the summer plate count agar only.The plates were placed on a the ambient temperature is high and lacking of colony counter and the number of bacterial colonies refrigeration in the situation of long distance milk was recorded.The blood agar and DNase test media transportation helps the situation [17,18].were inoculated and incubated at 37°C for 24 hours [9, Table -2 shows the highest rate of isolates in the 10].On the pasteurized samples, the lactose broth with raw milk orderly as follow: coliforms, E. coli, and S. dilution of 1, 0.1, 0.01 was prepared and incubated at aureus.The highest mean value of Total Plate Count 37°C for 24 hours.For identification of S. aureus, on was found in milk from the southwest region with 3 -1 each blood agar and EMB media, 0.1 ml of milk sample 1.91×107±2.8×10cfu/ml , while the lowest mean  2.2×10 , 2.1×10 ±101, and 1.3×10 ±137 cfu/ml ,

Results and Discussion
respectively.Detection of E. coli in milk often reflects manure contamination, soil and contaminated water, In this research, total of 300 raw milk sample was and poor hygienic practices in dairy environment studied.In the raw milk samples, contamination with although environmental coliforms have also been coliforms, E. coli, and S. aureus was observed in 237 detected in milk.E. coli and coliform bacteria are often (79%), 207 (69%) and 125 (41.66%), respectively used as indicator microorganisms, and the presence of (Table-1).Report given by Nihar in India indicated, E. coli a risk that other pathogens may be present in the that of the 144 samples, Staphylococcus was found in samples.Presence of S. aureus in milk may originate sampled from five different regions in Shahrekord from mastitic animals [19], or human sources.The total township contained identified pathogens.The prevaplate count, coliforms, E. coli and S. aureus counts for lence and concentration of the pathogens included in raw milk significantly differed (P<0.05)amongst the the study were relatively high.Recognition rates for E. study regions.In similar studies, report on coli, coliforms, and S. aureus were generally higher contamination of the raw milk samples in Zimbabwe than those found from in other countries.Recommenwas similar to this study [20].Report of the raw milk dations for solving this problem includes і) Educating samples in Greece show that From the 240 milk the farmers on general hygienic practices, quickening samples tested, only 5% were E. coli positive, with the delivery of milk to collection centres, or availing boiling of milk prior to consumption.Overall, on farm coliforms (9.1×10 cfu/ml) and E. coli in 1.7% of the samples.Hill et al reported that in New Zealand, [22] production of milk must ensure that the milk is produced 2 by healthy animals under generally accepted conditions E. coli, 99% of samples tested had counts <10 cfu/ml 3 such as: animal's health, milking health, animals and only 0.7% were >10 cfu/ml and S. aureus, the feeding and water, animal's welfare, and environment.results show that 60% of the raw milk samples 2 2 contained <10 cfu/ml and 30% contained between 10 The most rate of contamination was in the Catalase test, Indole, Methyl red, Voges-Proskauer samples from southwest region with coliforms, E. coli, test, Nitrate reduction, Urease production, Simmon's and S. aureus 30 (100%),29 (96.66%) and 19(63.33%),citrate agar and various sugar fermentation tests.For respectively (p<0.05) (Table-1).The rate of contamiisolation and colony counting of S. aureus the medium nation of raw milk prepared during summer with blood agar and DNase media were inoculated and coliforms, E. coli, and S. aureus with 30 (100%), 29 incubated at 35°C for 24 hours, the catalase and

Table - 1
: Contamination of raw cow milk samples by coliform, E. coli and S. aureus

Table - 2
: Mean counts of total plate counts, coliform, E. coli and S. aureus in raw cow milk sample collected from region of Shahrekord city.

Table - 3
: Microbial load in milk samples collected from five region of Shahrekord city, Iran