OCCURRENCE OF STAPHYLOCOCCUS AUREUS, SALMONELLA SPECIES AND LISTERIA MONOCYTOGENES IN FARMS AND MARKETS MILK

M.O. MOHAMMED, GIHAN; KOATB, EBTSAM E.Z.; A. EL-DAHSHAN, HANAN; A. AIDEIA, HOADA

doi:10.21608/avmj.2012.172756

OCCURRENCE OF STAPHYLOCOCCUS AUREUS, SALMONELLA SPECIES AND LISTERIA MONOCYTOGENES IN FARMS AND MARKETS MILK

Document Type : Research article

Authors

¹ Dept. of Bacteriology and Food Hygiene, Animal Health Research Institute, Port- Said Laboratory

² Animal Reproduction Research Institute.

³ Dept. of Bacteriology and Food Hygiene, Animal Health Research Institute, Port- Said Laboratory.

⁴ Dept. of Food Hygiene, Animal Health Research Institute, Dokki.

10.21608/avmj.2012.172756

Abstract

A total of 200 random samples of milk from dairy shops, farms and markets (100 farm's milk samples from Cairo, 50 milk samples from different dairy shop in Port-Said and 50 samples of Ultra heat Treatment (UHT) milk from different Port-Said city markets) for isolation and identification of Staph aureus, Salmonella speciesand Listeria monocytogenes. The results revealed that the staph aureus could be detected in 9% and 28% of farm's and dairy shops milk samples, respectively, with count values 3.6 x10²and5.2x10², respectively. Out of 14 strains obtained from dairy shops milk, only two were enterotoxigenic belonging to type A&D and C. Nine Staph aureus were obtained from farm's milk, one was enterotoxigenic belonging to type A. While, Salmonella speciesand Listeria monocytogenes wereisolated fromfarm's milk only in percent of 5% and 4 %, respectively. The isolated Salmonella serotypes were Salmonella anatum (one isolate) and Salmonella typhimurium (four isolates). On the other hand the Ultra Heat Treatment (UHT) milk from different markets were free from Staph aureus, Salmonella speciesand Listeria monocytogenes. The public health hazard of these microorganisms as well as recommended measures to improve quality status of milk were discussed.

Keywords

Full Text

OCCURRENCE OF STAPHYLOCOCCUS AUREUS, SALMONELLA SPECIES AND LISTERIA MONOCYTOGENES IN FARMS AND MARKETS Milk

Gihan M.O. Mohammed^*, Ebtsam E.Z. Koatb^**, Hanan A. El-Dahshan^* and Hoada A. Aideia^***

* Dept. of Bacteriology and Food Hygiene, Animal Health Research Institute,
Port- Said Laboratory.

** Animal Reproduction Research Institute.

*** Dept. of Food Hygiene, Animal Health Research Institute, Dokki.

___________________________________________________________________________

ABSTRACT

________________________________________________________________

Received:7/2/2012

Accepted:4/3/2012

_________________________________________________________________________________ Key words: Milk, Farms, Dairy shops, Markets, Ultra heat Treatment (UHT) milk, foodborne disease (Staph auras, Salmonella species and Listeria monocytogenes), Public health.

_________________________________________________________________________________

مدي تواجد ميکروب العنقودي الذهبي والسالمونيلا والليستيريا منوسيتوجينز

في ألبان المزارع والمحلات

جيهان محمد عمر محمد ، ابتسام السيد زکى قطب ، حنان أمين الدهشان ، هدى أمين عايدية

يعد اللبن من الأغذية الواسعة التداول لدى الکبار والأطفال ، وتلوثه بالميکروبات الضارة من الأمور التي تستوجب الاهتمام والدراسة، من هنا کان الاهتمام بتحديد مدي تواجد کل من الميکروب المکور العنقودي الذهبي، ميکروبات السالمونيلا وأيضا ميکروب الليستيريا منوسيتوجينز لما لهم من خطورة کبيرة علي الصحة العامة للإنسان ، لذلک تضمنت هذه الدراسة فحص 100 عينة عشوائية من المزارع و 50 عينة من محلات الألبان و 50 عينة من اللبن المعالج بالحرارة من المحلات المختلفة. وأظهرت النتائج تواجد ميکروب المکور العنقودي الذهبي في عينات اللبن من المزارع والمحلات بالنسب الآتية 9 %، 28% علي التوالي وکذلک کان العـد البکتيـري الکلي للميکـروب بالنسـب ² 10x3,6، ²10 x 5,2علي التوالي. وتم تصنيف العترات المعزولة من عينات اللبن من المزارع والمحلات لمدي إفرازها للسموم ولوحظ أن نوع السم A,C,A&D بينما کانت العينات اللبن المعامل حراريا خالية من الميکروب المکور العنقودي الذهبي . وأما بالنسبة لکل من ميکروبات السالمونيلا وميکروب الليستيريا منوسيتوجينز قد تم عزلهما بنسبة 5%، 4% علي التوالي من عينات اللبن من المزارع فقط. وقد تم تصنيف العترات المعزولة من السالمونيلا إلي عتره Salmonella anatum"" وأربع عترات "Salmonella Typhimurium". وأظهرت أيضا أن کل عينات اللبن المعالج بالحرارة من المحلات المختلفة خالي من ميکروب المکور العنقودي الذهبي، ميکروبات السالمونيلا وميکروب الليستيريا منوسيتوجينز. هذا وقد تمت مناقشة الأهمية الصحية لهذه الميکروبات ومدى تأثيرها على الصحة العامة للإنسان وکذلک الشروط الواجب توافرها وإتباعها للمحافظة على سلامة اللبن.

INTRODUCTION

Milk is nutritious food for human which plays an important role in human diet all over the world, but at the same time it is a good medium for the growth of a wide range of micro-organisms especially pathogens. The presence of such organisms in milk represents a major public health concerns (Ryser, 1998). Milk can carry dangerous bacteria such as Salmonella species, Staph aureus and Listeria monocytogenes, which are responsible for causing numerous foodborne illnesses (De Buyser et al., 2001 and Oueslati et al., 2011). Bacteria multiply rapidly in milk due to its rich nutritional composition. In thisconcernBoycheva et al. (2003), studied bacterial quality of milk and found different types of bacteria in milk like Listeria species and Staphylococcusspecies. These harmful bacteria can seriously affect the health of anyone who drinks raw milk, or eats foods made from raw milk. However, the bacteria in raw milk can be especially dangerous to pregnant women, children, the elderly, and people with weakened immune systems.

Staphylococcal food poisoning is a common form of foodborne illness, which results from ingestion of toxins produced by toxigenic strains of Staph aureus. Enterotoxins are groups of single chain protein (polypeptides) with molecular weight ranging from 28.000 to 35.000 Daltons, resistant to high temperature (heat stable) and proteolytic enzymes. The enterotoxigenic strains of Staph aureus produce several types of enterotoxins (A, B, C, D and E) which can cause symptoms of intoxications such as vomiting, diarrhoea and abdominal cramping (Korpysa et al., 2005). Staph. Enterotoxin A (SEA) is

recent years (Choi and Hong, 2003). Listeria monocytogenes associated with septicemia, meningoencephalitis and abortion in humans and animals, primarily affecting pregnant, new-born, and immuno-compromised individuals (Choi and Hong, 2003; Rossmanith et al., 2006, Mugampoza et al., 2011). Several outbreaks of listeriosis were proven to be associated with the consumption of milk and are causing great concern in the dairy industry due to high mortality rate (nearly 30%) of these outbreaks (Amagliani et al., 2004). Listeria monocytogenes can gain entry to the milk from faecal contamination of the udder. Once introduced into the milking equipment, Listeria monocytogenes can readily colonize these moist environments. Listeria monocytogenes is found commonly in wet areas of dairy plants, such as floor drains, conveyers, floors and stainless steel equipment (Bell and Kyriakides, 2002).

Contamination of milk and dairy products by pathogenic micro-organisms can be of endogenous origin, following excretion from the udder of an infected animal or may be also of exogenous origin, through direct contact with infected herds or through the environment (e.g. water and personnel, etc.). Bacteria most frequently involved are Listeria monocytogenes, Staphylococcus aureus and enterobacteria (including Salmonella) (Brisabois et al., 1997) and (Ben Hassen et al., 2003). High microbial counts in milk usually result in inferior quality of milk (Costello et al., 2003). Adulteration of milk, affect also compositional and microbiological quality of milk. In Egypt; climatic conditions; low level of sanitation during production; transportation and handling are responsible for low quality of milk and dairy products (Girgis et al., 1996).

This study is planned to investigate the presence of Staph aureus, Salmonella speciesand Listeria monocytogenes in milk with regarding to the public health.

MATERIALS and METHODS

1- Samples collection:

A total of 200 random samples of milk were collected from different farms in Cairo,

responsible for majority of staphylococcal food poisoning whereas Staph Enterotoxin B (SEB) is rarely involved (Robbins et al., 1974). In addition, most outbreaks as recorded by Halpin-Dohnalek and Marth (1989) resulted from the combined effect of contamination of food with Staph aureus often through unsanitary handling, and holding the food at the wrong temperature thus enhance growth and synthesis of enterotoxins. However, the enterotoxication generally is not lethal and the elderly are more susceptible than younger individuals. The concentration of enterotoxin necessary to cause intoxication is very small about 94-184 ng (Erol and Iseri, 2004).

Salmonella species are the most prevalent pathogens in the food industry. Studies about these microorganisms date up to 100 years and have been the causative agent on several outbreaks of foodborne diseases particularly in dairy products. Most of species are pathogenic. The primary habitat of Salmonella species is the intestinal tract of animals and humans. Milk is an important vehicle for Salmonellae causing human infection. Additionally Salmonella species causes illness by means of infection. They multiply in the small intestine, colonizing and subsequently invading the intestinal tissues, producing an enterotoxin and causing an inflammatory reaction and diarrhea (ICMSF, 2006).

Listeria species, cause the infection of listeriosis in both animals and man, Listeria monocytogenes is a major pathogenic microorganism (Aygun and Pehlivanlar, 2006). Listeriosis caused by Listeria monocytogenes has increased drastically in

different dairy shops and different markets in Port-Said city (100 samples of farm's milk from Cairo, samples of dairy shops from Port-Said 50 city and 50 samples of Ultra Heat Treatment (UHT) milk from markets in different localities in Port-said city for detection of Staph aureus, Salmonellaspeciesand Listeria monocytogenes. The samples were collected in clean, dry and sterile containers. Collected samples were transferred in an ice box and transported to the laboratory as soon as possible to be examined.

2- Bacteriological examination:

2-1 Staphylococcus aureus:

Twenty-five ml of each dairy shops, farm's and Ultra Heat Treatment (UHT) milk samples were homogenized in a stomacher for 2 min in 225 ml of Buffered peptone water,and Staphylococcus aureus was enumerated on Baird-Parker with Rabbit Plasma Fibrinogen (BP+RPF, Oxoid) after incubation for 48 h at 37 ^oC ISO, 6888-2(1999).

2-1-1 Detection and typing of Enterotoxins from Staphylococcus aureus: according to the method recommended by (Oda et al., 1979 and Shingaki et al., 1981). Passive Latex agglutination technique using Oxoid SET-RPLA [A kit for the detection of Staphylococcal enterotoxins A, B, C and D].

2- 2 Salmonella species: Twenty-five ml of each dairy shops, farm's and Ultra Heat Treatment (UHT) milk samples were homogenized in a stomacher for 2 min in 225 ml of Buffered peptone water, and incubated at 37°c ± 1°c for 18±2 hr. Isolation and identification according to the method recommended by ISO, 6579 (2002).

2-3 Listeria monocytogenes: Twenty-five ml of each dairy shops, farm's and Ultra Heat Treatment (UHT) milk samples were homogenized in a stomacher for 2 min in 225 ml of Listeria enrichment broth (Difco), and incubated at 30°c for 48 hr. Isolation and identificationaccording to the method recommended by ISO, 11290-1 (2011).

RESULTS

Table 1: Incidence of Staph aureus, Salmonellaspecies and Listeria monocytogenes in examined samples of milk from farms, dairy shops and markets.

Location	Examined samples	No. of examined samples	Isolated strains
			Staph aureus		Salmonella species		Listeria monocytogenes
			No.	%	No.	%	No.	%
Cairo	Farm's milk	100	9	9%	5	5%	4	4%
Port-Said	Milk from Dairy shops	50	14	28%	0	0%	0	0%
Port-Said	Ultra heat treatment milk from markets	50	0	0%	0	0%	0	0%

Table 2: Staph aureuscount / ml of the positive milk samplesfrom farms, dairy shops and markets.

Examined samples	Minimum	Maximum	Average
Farm's milk	2 x10²	5 x10²	3.6x10²
Milk from Dairy shops	1x10²	6x10²	5.2x10²
Ultra heat treatment milk from markets	0	0	0

Table 3: Typing of Staphylococcus aureus strains enterotoxins isolated from the examined milk from farms dairy shops and markets.

Type of examined samples	No. of strains tested	Enterotoxigenic strains		Type of Enterotoxins
Type of examined samples	No. of strains tested	No.	%	A	C	A &D
Farm's milk	9	1	11.1%	1	-	-
Milk from Dairy shops	14	2	14.2%	-	1	1
Ultra heat treatment milk from markets	0	0	0	-	-	-

Table 4: Antigenic structure of different Salmonellae isolated from the examined farm's milk.

Salmonella serovars	Sero-group	Antigenic structure
		[O]	[H]
		[O]	Phase (1)	Phase(2)
Salmonella Typhimurium	B	1,4,[5],12	i	1,2
Salmonella anatum	E1	3,10 [15] [15,34]	e,h	1,6

Table 5: Salmonellaserotypes isolated from the examined farm's milk.

Serotypes	No	%
Salmonella typhimurium	4	4%
Salmonella anatum	1	1%

Table 6: Distribution of Listeria monocytogenes in positive samples of farm's milk.

Listeria species

Farm's milk

Listeria monocytogenes

DISCUSSION

Milk contaminated with disease-causing bacteria does not smell or look any different from non-contaminated milk, and there is no obvious way for the consumer to know if the milk is contaminated (Julia, 2010). Pathogenic bacteria in milk has been a major factor for public health concern since the early days of the dairy industry. Many diseases are transmissible via milk products. Traditionally raw or unpasteurized milk has been a major vehicle for transmission of pathogens (Vasavada, 1988). The health of dairy herd, milking conditions are basic determinant of milk quality. Another source of contamination by microorganisms is unclean teats. The use of unclean milking and transport equipment contributed also to the poor hygienic quality (Bonfoh et al., 2003).

As seen from Table (1). The incidence of Staph aureus was isolated from 9 (9%) farm's milk and 14 (28%) in milk from dairy shops, These results were nearly similar to those reported by Abdel-Hameed et al. (2004) who isolated Staph aureus from raw milk samples in proportion of 14.38%. However, the current results were less than those recorded by Chye et al. (2004), Letiţia et al. (2011) and Ekici et al. (2004) they showed that Staph aureus was isolated from more than 60%, 70% and 75% of the raw milk samples and higher than those found by Abdel-Hameed (2006). Tondo et al. (2000) reported that 35.2% of food handlers were asymptomatic carriers of Staphylococcus aureus, and that 90.4% of raw milk samples. While Salmonella species were isolated fromfarm's milk only in percentage of 5% the results were higher than those recorded by De Reu et al. (2004) and Abd El-Atty and Meshref (2007) who couldn't detected Salmonella species in raw milk samples.

Listeria monocytogenes wereisolated fromfarm's milk only in percentage of 4%. The above mentioned results were higher than those reported by Jensen et al. (1996) who demonstrated Listeria monocytogenes in only 1.2% of milk samples. However, the results were less than those recorded by

(Rohrbach et al., 1992), Canada 1.9% (Fedio and Jackson, 1990) and Iran 1.6% (Moshtaghi and Mohammadpour, 2007). The disparate levels of contamination which have been reported from localized studies might have been due to variations in regions or to variations in sampling and detection techniques.

Food-borne disease outbreaks associated with Salmonella have been known for a long time and continue to be a problem in both developed and developing countries (Bean et al., 1990). Most outbreaks have implicated foods containing eggs or poultry products. Nevertheless, there have been several outbreaks of salmonellosis for which milk or milk products were responsible. Contamination of milk usually takes place by Salmonellae from external sources. Sources can be faeces, the farmer or his family, polluted water, dust etc. Healthy cows can also regularly excrete Salmonellae in their dung. Salmonellosis is caused by the ingestion of living bacteria of the Salmonella group. In contrast to staphylococcal food poisoning, the ingestion of viable cells is necessary for salmonellosis. The number of cells which have to be ingested to cause disease varies according to the type of strain, the type of food consumed and the consumer. Numbers varying from one cell of Salmonella typhi to several millions of, for example Salmonella derby or Salmonella anatum, are mentioned (D’Aoust, 1989). Infants as well as very young and aged people are especially sensitive and a smaller dose can result in disease. In the present study, Salmonellae were isolated from farm's milk in a percentage of 5%. None of the milk form dairy shops and ultra heated milk from markets contained Salmonella species. Salmonellae are sensitive to heat treatment and are readily destroyed at milk pasteurization temperatures. Pathogenic bacteria in milk has been a major factor for public health concern since the early days of the dairy industry. Many diseases are transmissible via milk products. The health of dairy herd, milking conditions are basic determinant of milk quality. Another source of contamination by microorganisms is

REFERANCES

Abd El-Atty, N.S. and Meshref, A.M.S. (2007): Prevalence of Salmonella and E.coli O157 in some foods. Beni - Suef Veterinary Medical Journal, 5^th Scientific Conference: 73-78.

Abdel-Hameed, K.G.; Sender, G.; Prusak, B. and Ryniewicz, Z. (2004): Multiplex PCR protocol for the diagnosis of cow udder infection with Staphylococcus aureus. Animal Science Papers and Reports, 22 (4): 679-685.

Abdel-Hameed, K.G. (2006): Association of the BoLA-DRB3 polymorphism with occurrence of mastitis caused by with Staphylococcus aureus and Streptococcus agalactiae. PhD Thesis. Institute of Animal Breeding and Genetics. Polish Academy of Science, Poland.

Adesiyun, A.A.; Webb, L.A.; Romain, H. and Kaminjolo, J.S. (1996): Prevalence of Salmonella, Listeria monocytogenes, Campylobacter spp., Yersinia enterocolitica and Cryptosporidium spp. in bulk milk, cows’ faeces and effluents of dairy farms in Trinidad. Rev. Elev. Med. Vet. Pays Trop., 49: 303-309.

Amagliani, G.; Brandi, G.; Omiccioli, E.; Casiere, A.; Bruce, I.J. and Magnani, M. (2004): Direct detection of Listeria monocytogenes from milk by magnetic based DNA isolation and PCR. Food Microbiol., 21: 597-603.

Aygun, O. and Pehlivanlar, S. (2006): Listeria spp.in the raw milk and dairy products in Antakya, Turkey. Food Control. 17: 676-679.

Baird-Parker, A.C. (1990): The staphylococci: an introduction. J. Appl. Bact. Symp. Suppl., 1S-8S.

Bell, C. and Kyriakides, A. (2002): Listeria monocytogenes. In: Blackburn, C.; de, W. and McClure PJ. Eds. Foodborne pathogens: Hazards, Risk Analysis and Control. Boca Raton: CRC Press Taylor & Francis Group.

Bean, N.H.; Griffin, P.M.; Goulding, J.S. and Ivey, C.B. (1990): Foodborne

Chye, F.Y.; Abdullah, A. and Ayob, M.K. (2004): Bacteriological quality and safety of raw milk in Malaysia. Food Microbiology 21(5): 535-541.

De Buyser, M.L.; Dufour, B.; Maire, M. and Lafarge, V. (2001): Implication of milk and milk products in food-borne disease in France and different industrialized countries. – Int. J. Food Microbiol. 67: 1-17.

D'Aoust, J.Y. (1989): Manufacture of dairy products from unpasteurized milk: a safety assessment. Journal of Food Protection, 52: 906-914.

De Reu, K.; Grijspeerdt, K. and Herman, l. (2004): A Belgian survey of hygiene indicator bacteria and pathogenic bacteria in raw milk and direct marketing of raw milk farm products. Journal Of Food Safety, 24(1): 17-36.

Deutz, A.; Pless, P. and Koefer, J. (1999): Examination of raw cows and ewes milk for human pathogens. Ernaehrung. 23: 359-362.

Egyptian Organization for Standardization and Quality (2005): UHT milk. E.S. 1623/2005.

Ekici1, K.; Bozkurt, H. and Isleyici, O. (2004): Isolation of some pathogens from Raw milk of different milch animals. Pakistan Journal of Nutrition 3 (3): 161-162.

Erol, I. and Iseri, O. (2004): Staphylococcal Enterotoxins. Ankara Universitesi Veteriner Fakultesi Dergisi, 51(3): 239-245.

Fedio, W.M. and Jackson, H. (1990): Incidence of Listeria monocytogenes in raw bulk milk in Alberta. Food Res. Int., 23: 236-238.

Gaya, P.; Sanchez, J.; Medina, M. and Nunez, M. (1998): Incidence of Listeria monocytogenes and other Listeria species in raw milk produced in Spain. Food Microbiol., 15: 551- 555.

Girgis, E.S.; Soad, H.T.; Laila, Y.M. and Hala, A.A. (1996): Incidence of psychrotrophic bacteria in local buffaloۥ s market milk. Egyptian J. Dairy Sci., 24:91.

Letiţia, O.; Ramona, I.; Eniko, G. and Ecaterina, L. (2011): Pathogenic Microorganisms from Raw milk of Different Animals.Oprean L. et. al./Scientific Papers: Animal Science and Biotechnologies, 44 (1): 439-441.

Moshtaghi, H. and Mohammadpour, A.A. (2007): Incidence of Listeria spp. in raw milk in Shahrekord (Iran). Foodborne Pathog. Dis., 4: 107-110.

Mugampoza, D.; Muyanja, C.M.B.K.; Ogwok, P.; Serunjogi, M.L.
and Nasinyama, G.W. (2011): Occurrence of Listeria monocytogenes in bulked raw milk and traditionally fermented dairy products in Uganda. African Journal of Food, Agriculture, Nutrition and Development, 11 (2): 4610- 4622.

Olsvic, O.; Berdal, B.P.; Fossum, K. and Omland, T. (1982): Enterotoxin production of Staphylococcus aureus related to the origin of the strains. Acta Path. Microbiol. Scand. Sect. B. 89: 423.

Oda, T.; Chkuboty, T.; Nagai, M.; Nishimoto, Y. and Ohmaruk, K. (1979):Ann. Rep.FukuokaCity Lab. Hyg, 2.33 (Cited after Oxoid Limited Wade Road Basingstoke Hampshire RG24 OPW England).

Oueslati, S.; Ennouri, H.; Bamri, H.; Ben, M.O. and Oueslati, R. (2011): Differential Distribution of Pathogens from Raw milk and Place of Shigella by Mode of Milking. African Journal of Food Science and Technology (ISSN: 2141-5455) Vol. 2(8) pp. 179-183.

Riadh, A.T. (2005): A Comparison on Microbial Conditions Between Traditional Dairy Products Sold in Karak and Same Products Produced by Modern Dairies. Pakistan Journal of Nutrition 4 (5): 345-348.

De Reu et al. (2004) who could isolate Listeria monocytogenesin percentage of 6.3%. Poor hygiene often arises from poor handling at the farm, at collection centers, during transportation and at retail points. Common sources of bacterial contamination, especially coliforms, are faeces (of animal or human origin), personnel, water and containers. A high bacterial count reduces the shelf life of milk and enhances the risk of milk-borne bacterial infections and intoxications if the milk is not properly heated or if thermal injured pathogens recover under suitable temperatures (Kayihura et al., 1987).

Coagulase - positive Staphylococci species enterotoxin-producing staphylococcal species, Staphylococcus aureus in particular, are the leading cause of food-borne illness throughout the world. Sickness results from the ingestion of one or more preformed staphylococcal enterotoxins in staphylococcus contaminated food. The pathogenicity of Staphylococcus aureus has been recognized for many years, it may cause mastitis and/or skin diseases in milk-producing animals or lead to 36type of food-borne intoxications in consumers of milk and milk products (Bolstridge and Roth, 1985). Contamination with coagulase-positive Staphylococci was particularly high in raw milk from different farms and Markets (above 5x10² cfu/ml). The source of this contamination is difficult to trace due to the ubiquitous nature of staphylococci. Staph aureus is carried in the nose of some 30% of persons, who also tend to be skin carriers, and it is frequent in a number of animals (Olsvic et al., 1982). The enterotoxins of Staphylococci are remarkably resistant to heat. Baird-Parker (1990) states the temperature conditions for destruction of Staphylococcus aureus to be: 0.43 – 8 minutes at 60°C compared to 3 – 8 minutes at 121°C for enterotoxin.

In this study, the prevalence of Listeria. monocytogenes (4%) was found in farm^'s milk. Similar frequency findings of Listeria monocytogenes (0-5%) raw milk samples have been reported from different countries such as Austria 1.5% (Deutz et al., 1999), Spain 3.6% (Gaya et al., 1998), India 1.7% (Adesiyun et al., 1996), USA 4.1%

unclean teats. The use of unclean milking and transport equipment contributed also to the poor hygienic quality (Bonfoh et al., 2003). The machine-milking may increase the incidence of mammary infections either by a role as vectors of pathogens from infected areas to healthy neighborhoods, either by contamination of the teat force, its role is traumatic for the teat canal, while diminishing effect "barrier" (Boudry, 2005). As a result of the research, the samples of milk examined contained pathogenic microorganisms. This may indicate that analyzed milk can contribute a potential risk for public health in the cases that it is consumed or used in the production of dairy products such as cheese, butter, cream and ice cream without being pasteurized or being subjected to a sufficient heat process.

In this study the Ultra Heat Treatment milk (UHT) from markets was free from Staph aureus, Salmonella speciesand Listeria monocytogenes. This result agree with the (Egyptian standard, 2005) and (Riadh, 2005) who mentioned that the UHT milk should be free from pathogenic microorganisms.

Conclusion

The presence of Staph aureus, Salmonella speciesand Listeria monocytogenes in farm's milk and milk from dairy shops samples recorded in this study is expected as the produced milk is liable to contaminate from different sources (dust, air, water, equipments, milkers and handlers), moreover, the prevailing of bad handling, poor sanitation of equipments and lake of cooling facilities during transportation. Ultra Heat Treatment milk (UHT) from markets which are free from any pathogens indicated that Ultra Heat Treatment milk (UHT) is fit for human consumption because it gave a real indication for the good hygienic practice during production and handling.

disease outbreaks, 5-year summary, 1983-87. Morbidity and Mortality Weekly. Report, 39 (SS-l), 15-57.

Ben Hassen, S.; Messadi, L. and Ben Hassen, A. (2003): Identification et caractérisation des espèces de Staphylococcus isolées de lait de vaches atteintes ou non de mammite. Ann. Méd. Vét. 147: 41-47.

Bolstridge, M.C. and Roth, G. (1985): Enterotoxigenicity of strains of Staphylococcus aureus isolated from milk products. South Afr. J. Dairy Technol. 17: 91-95.

Bonfoh, B.; Wasem, A.; Traore, A.N.; Fane, A.; Spillmann, H.; Simbe, C.F.; Alfaroukh, I.O.; Nicolet, J.; Farah, Z. and Zinsstag, J. (2003): Microbiological quality of cow’s milk taken at different intervals from the udder to the selling point in Bamako (Mali). Food Control, 14: 495-500.

Boudry, B. (2005): Traire un lait de qualité: Une attention de tous les jours Qualité du lait et gestion du troupeau. Journée d'étude des AREDB d'Aubel, de Herve-Fléron-Visé et de Montzen et de la Région wallonne -DGA - Direction du Développement et de la Vulgarisation.

Boycheva, S.; Dimitrov, T.; Tsankova, M. and live, T. (2003): Investigation on micro flora of buffalo milk, Bulgarian J. Agric. Sci. 8: 279-282.

Brisabois, A.; Lafarge, V.; Brouillaud, A.; de Buyser, M.L.; Collette, C.; Garin-Bastuji, B. and Thorel, MF. (1997): Pathogenic organisms in milk and milk products: the situation in France and in Europe. Rev. Sci. Tch., 16(2): 452-71.

Costello, M.; Rhee, M.S.; Bates, M.P.; Clark, S.; Luedecke, L.O. and Kang, D.H. (2003): Eleven-year trends of microbiological quality inbulk tank milk. Food Prot. Trends. 23: 393–400.

Choi, W.S. and Hong, C.H. (2003): Rapid enumeration of Listeria monocytogenes in milk using competitive PCR. Int. J. Food Microbiol., 84: 79-85.

Halpin-Dohnalek, M.I. and Marth; E.H. (1989): Staphylococcus aureus: production of extracellular compounds and behaviour in foods. J. Food Prot.,52 (4): 267-282.

ICMSF (2006): Microorganism in Foods, Microbial ecology of food commodities. 2nd ed. Kluwer Academics, Plenum Publishers. Londres, U.K.

ISO (1999): Microbiology of food and animal feeding stuffs - Horizontal method for the enumeration of coagulase-positive staphylococci (Staphylococcus aureus and other species)- Technique using rabbit plasma fibrinogen agar medium. International Standard ISO 6888-2, International Organisation for Standardization, Geneva.

ISO (2002): Microbiology of food and animal feeding stuffs- Horizontal method for detection of Salmonella spp. ISO 6579 Organisation for Standardization.

ISO (2011): Microbiology of food and animal feeding stuffs- Horizontal method for the detection and enumeration of Listeria monocytogenes. Part 1: Detection method. ISO11290-1 Organisation for Standardization.

Jensen, N.E.; Aarestrup, F.M.; Jensen, J. and Wegener, H.C. (1996): Listeria monocytogenes in bovine mastitis. Possible implication for human health. Int. J. Food Microbiol., 32: 209–216.

Julia, H. (2010): Illness Outbreaks in Utah Linked to Raw milk. News Release, Monday, May 16.

Kayihura, M.; Kaburia, H.F.A.; Arimi, S.M. and Lindquist, K.J. (1987): Staphylococcal enterotoxin A in raw and pasteurized milk. East African Medical Journal. 64: 177-181.

Korpysa, W.; Rola, J.G. and Osek, J. (2005): Staphylococcal enterotoxins and their detection in milk and milk products. Medycyna Weterynaryjna, 61(6): 633-636.

Robbins, R.N.; Gould, S. and Bergdoll, M. S. (1974): Detecting theenterotoxigenityof Staphylococcus aureusstrains. Applied Microbiology, 28: 946-950.

Rohrbach, B.W.; Draughon, F.A.; Davidson, P.M. and Oliver, S.P. (1992): Prevalence of Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica, and Salmonella in bulk tank milk: risk factors and risk of human exposure. J. Food Prot., 55: 93-97.

Rossmanith, P.; Krassnig, M.; Wagner, M. and Hein, I. (2006): Detection of Listeria monocytogenes in food using a combined enrichment/real-time PCR method targeting the prf A gene. Res. Microbiol., 157: 763-771.

Ryser, E.T. (1998): Public health concems. In: Marth, E.H., Steele, J.L. (Eds), Applied Dairy Microbiology. Marcel Dekker, Inc., New York, pp.263.

Shingaki, S.; Igarashi, H.; Fujikawa, H.; Ushioda, H.; Terayama, T. and Sakai, S. (1981): Study on reversed passive latex agglutination for the detection of staphylococcal enterotoxins A-C. Annu Rep Tokyo Metr. Res. Lab. Publ. Hlth. 32: 128-131.

Tondo, E.C.; Guimarães, M.C.M.; Henriques, J.A.P. and Ayub, M.A.Z. (2000): Assessing and Analysis contamination of Dairy Products Processing Plant by Staphylococcus aureus using antibiotic resistance and PFGE. Can. J. Microbial., 46: 1108- 14.

Vasavada, P.C. (1988): Pathogenic bacteria in milk. A Review. J. Dairy Sci., 71: 2809–2816.