INCIDENCE OF SALMONELLAE IN CHILLED CHICKEN CARCASSES IN RETAILS PORT-SAID CITY

INCIDENCE OF SALMONELLAE IN CHILLED CHICKEN CARCASSES IN RETAILS PORT-SAID CITY

NAHLA T. KORASHY^* and GIHAN M.O. MOHAMMED^**

^* Microbiology department, Port-Said Lab., animal health research institute, Dokki, Giza, Egypt.

^** Microbiology department, Port-Said Lab., animal health research institute, Dokki, Giza, Egypt.

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                                           ABSTRACT

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Key words: Salmonella, chilled chicken, Port-Said City.

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INTRODUCTION

Poultry meat constitutes a substantial portion of protein in the present day diets, hence it has an important share (30%) in the world's total meat consumption (Del Rio et al., 2007). Poultry meat can be contaminated with a variety of foodborne pathogens (Mor-Mur and Yuste, 2010). The presence of pathogenic microorganisms, spoilage microorganisms or both in Poultry is undesirable but unavoidable (Goncalves et al., 2004). Salmonellosis is an important global public health problem causing substantial morbidity, and thus also has a significant economic impact. In spite of the improvement in hygiene, food processing, education of food handlers and information to the consumers, foodborne diseases still dominate as the most important public health problem in most countries. Dominguez et al. (2002).

Poultry meat and its derivatives are among the food products that cause the most concern to public health authorities, owing to the associated risks of bacterial food poisoning. The modernization of chicken farms and globalization of the bird breeding trade also have played a role in infection. Velge et al. (2005).

In humans, Salmonella is the cause of two diseases called salmonellosis: enteric fever (typhoid), resulting from bacterial invasion of the blood stream, and acute gastroenteritis, resulting from a foodborne infection/intoxication. It has been reported that 10-20% of Salmonellosis outbreaks were related to poultry meat consumption (Bailey, 2002). Most people infected with Salmonella develop diarrhea, fever, and abdominal cramps 6 to 72 hours after infection. In most cases, the illness usually lasts 3 to 7 days - most affected people recover without treatment. However, in some people the diarrhea may be so severe that the patient becomes dangerously dehydrated and must be taken to a hospital.

Poultry and poultry products are usually incriminated in outbreaks of human salmonellosis. Salmonella often reach the carcasses from the intestinal tracts or faecal materials on feathers or feet. Particularly scalding, defeathering, evisceration and giblet operations are the major points of spread in poultry processing plants (Bryan and Doyle, 1995), (D’aoust, 1989) and Uyttendaele et al. (1998).

The cross-contamination of hands of workers, working equipment and utensils could also serve as a mean of spread of Salmonella to uncontaminated carcasses and giblets in which contamination could continue during subsequent handling, processing and preparations. (Scott, 1996) and Uyttendaele et al. (1998).

Previous works undertaken in Egypt indicated the presence and distribution of Salmonella in wild birds (Azza, 2003), poultry farms (El-Jakee et al., 2010), laying farms (Mona, 2007), calves (Moussa et al., 2010), House sparrows and Laughing doves (Helal, 2007) poultry meat and meat products (Raafat et al., 2011) man (Weal et al., 2011). Various serotypes of Salmonella were also identified from House sparrows and Laughing doves, calves, poultry meat and man in Egypt (Helal, 2007; Moussa et al., 2010, Raafat       et al., 2011 and Weal et al., 2011).

A periodic surveillance of the level of Salmonella contamination in the different food animals, food products and environment is necessary to control the spread of the pathogen and infection of man (Arumugaswamy et al., 1995 and Dawson, 1992). The knowledge on the prevalent Salmonella serotypes in a country is also important in order to understand the distribution and means of introduction into a country Jegathesan (1984). This study was, therefore, undertaken to determine the prevalence and distribution of serotypes of Salmonella in chilled chicken carcass obtained from retails Port-Said city.

MATERIALS and METHODS

1-Sampling:

One hundred and twenty samples of each chilled chicken carcass (40 meat, 40 giblets and 40 drip) were randomly collected from different retails in Port- Said city. Each sample was obtained aseptically and transported in iceboxes packed with ice to laboratory as soon as possible to be subjected to bacteriological examinations.

2- Isolation and identification of Salmonella:

Salmonellae were isolated and identified according to the techniques recommended by the International Organisation for Standardisation (ISO, 2002).

2-1- Pre-enrichment in non selective medium:

Briefly, 25 g of each sample of meat and giblet was weighed and cut into smaller fine pieces with sterile scalpel blades. Each sample was put in a sterile stomacher bag and 225 ml of buffered peptone water (BPW; Difco, USA) was added, homogenized using a stomacher. In case of drip samples, pre-enriched in BPW in a ratio of 1ml of the sample to 9 ml of BPW. The pre-enriched Samples were incubated for 16 to 20 hours at 37°C.

2-2- Selective enrichment:

One ml and 0.1 ml of the pre-enrichment broth was transferred aseptically into each of 10 ml of Mauller Kouffmann Tetrathionate novobiocin broth (Difco, Detroit, USA) and 10 ml of Rappaport Vassiliadis soy broth (RVS; Oxoid) and incubated for 18 to 24 hours at 37°C and 42°C respectively.

2-3-Plating out on selective agar media:

Each enrichment culture was streaked on two selective agar media, xylose lysine deoxycholate agar (XLD; Oxoid) and Hektoen enteric agar (HE; Difco)and incubated at 37°C for 18 to 24 hours.

2-4- Selection of colonies  for purification:

From each selective media plate, at least one colony considered being typical or suspect was picked and streaked onto the surface of nutrient agar plate for further identification.

2-5- Identification of the isolates:

2-5-1- Microscopical identification of the isolates:

Smears from the purified colonies wear prepared and stained with Gram's stain method and examined microscopically for the morphological character of salmonella according to (Quinn et al., 2002 ).

2-5-2- Biochemical  identification:

Salmonella spp. isolates were identified biochemical by Triple sugar iron agar, Lysine iron agar, and urea then by Microbact-12A test kit.

2-5-3- Serotyping of salmonella isolates:

Colonies with biochemistry profile of Salmonella were serologically confirmed using diagnostic polyvalent (O, H) and monovalent Salmonella anti-sera. Suspected salmonella were cultured on TS agar slants for 24 h at 37°C. A loopfull from the culture was suspended in drop of phosphate buffer saline (pH 7.4) on a slide to make a homogenous suspension and then a drop of Salmonella anti-sera was added to the suspension and thoroughly mixed to bring the organisms in close contact with anti-sera. Positive agglutination occurred with in a minute. A delayed or partial agglutination was considered as negative or false reaction. (Kauffmann and Das- Kauffmann 2001)

RESULTS

Of the total of 120 samples examined, 11.7 % were contaminated with salmonellae (Table 1). A high level of salmonella contamination was found in giblet (5.8%) followed by drip (3.3%) and meat (2.5%).

Table 1: Prevalence of Salmonella isolated from chilled chicken carcasses.

Out of the total 14 salmonella isolates, 5 different serotypes were identified of which S. Typhimurium 42.9 was the most frequent followed by S. virchow 21.4%, S. enteritidis 21.3%, S.anatum 7.1% and Salmonella type Π 7.1%. (Table 2).  S.Typhimurium and S. enteritidis were isolated from all sample types (chicken meat, giblets and drip) while other serotypesisolated from giblets and drip. Most of the isolates belonged to the sero-group B. (42.9%) while the lowest number of the isolates belonged to sero-group E1 and type Π. (Table 3)

Table 2: Prevalenceof different Salmonella serovars recovered different samples.

       [n]Total number of isolates.                                                        [n=14]

       [%] calculated according to the total number of isolates. 

Table 3: Antigenic formula of   the isolated serovar.

DISCUSSION

Among the foodborne pathogens the genus Salmonella is one of the most common causes of foodborne infections worldwide (Baird-Parker, 1990). Characteristic feature of this organism is its wide host range, which comprises most animal species including mammals, birds and cold-blooded animals in addition to humans. It has been reported that Salmonella is one of the most important pathogens responsible for human food poisoning in the developed world, and chicken products are widely acknowledged to be a significant reservoir for Salmonella. Therefore, this organism has been isolated from a range of foods in almost every country in which it has been investigated Rajashekara et al. (2000). Chickens are commonly infected with a wide variety of salmonella serovars. Infections are generally sub-clinical and one serovar may be a predominant isolate in a country for several years before it replaced by another serovar (Wray et al., 1996). Bacteriological examination is the traditional mean to obtain accurate data about the prevalence of infected host of salmonellae (Commission of the European Communities, 1992).

In the present study, a total number of 120 chicken samples representing (40 meats, 40 giblet and 40 drip) were collected from different retails in port-said city for bacteriologically and serologically examination to detect the presence of salmonella species. 

The level of Salmonellacontamination of chilled chicken carcasses observed in our study (11.7%) was relatively high and confirms the findings of previous studies on Salmonella contamination in poultry and poultry products in Egypt (El-Jakee et al., 2010; Raafat et al., 2011).

A number of authors in different countries have reported different prevalence rates of Salmonella in poultry and poultry products 21.1 % in Ethiopia (Molla and Mesfin 2003), 22.8 % in UK (Plummer   et al. 1995), 35.5 % in Malaysia (Rusul et al., 1996), 35.8 % in Spain (Dominguez et al., 2002) and 36.7% in Belgium Uyttendaele et al. (1998).

The variation in the prevalence of Salmonella contamination could be partly due to differences in sample type, sampling techniques, distribution of salmonellae in a lot examined and the detection methods employed (Bryan and Doyle 1995; Dominguez et al., 2002; Rusul et al., 1996 and Uyttendaele et al., 1998).

In the present study out of the total 120 samples 40 were giblets (liver, heart and gizzard) had higher contamination level of Salmonella (5.8 %) while the meat samples had lower percent of contamination 2.5%. (Table 1). This was in agreement with the findings of (Jerngklinchan et al., 1994; Molla et al., 1999 and Boniphace 2001) who reported that prevalence rates of Salmonella in chicken giblets more than of the carcass samples.

On the other hand a high level of Salmonella contamination was detected in retail chicken meat and giblets (Arumugaswamy et al., 1995; Rusul       et al., 1996 and Carraminana et al., 1997).

Cross-contamination of Salmonella from giblets to carcass could occur during handling, processing, packing and distribution. The packing of giblets with the carcass observed in this study at processing plants could have also contributed to increase Salmonella cross-contamination. In addition to these, scalding water can become contaminated with Salmonella from faeces, plucking equipment, cages and floors. Workers can spread the contamination during retailing (Arumugaswamy et al., 1995 and Uyttendaele et al., 1998). Rupture of the intestine could also occur during evisceration and pooling giblets might lead to cross-contamination of carcasses and other chicken parts.

Out of the total 14 Salmonella isolates, 5 different Salmonella serotypes were identified (Table 2). The most prevalent serotypes were S. Typhimurium, followed by S. virchow and S. enteritidis. Our results come in agreement with Wafaa et al. (2012) who reported that S. Typhimurium and S. enteritidis were the most prevalent serotypes isolated from diseased and apparently healthy broiler chicken flocks in Egypt.

Other researchers have reported some of these serotypes in poultry meat and poultry products Carraminana et al. (1997); (Boniphace, 2001); Molla and Mesfin (2003). It should also be noted that the presence and distribution of Salmonella serotypes could vary from region to region (Uyttendaele et al., 1998 and Dominguez et al., 2002). While some serotypes emerge and decrease over time, others maintain their dominant role for many years with widespread distribution. The rapid international trade in agricultural, aquacultural and food products has also facilitated the introduction of new Salmonella serotypes into importing countries (D’aoust, 1994).

The high prevalence of S. Typhimurium observed in the present study reflects the presence of this serovar in the intestinal tract of live broilers, contaminating carcasses during slaughter and processing.

This study on poultry meat sale points revealed that most of the retails do not operate in a safe and clean environment, and rarely practice the appropriate covering for displayed carcass. Moreover, the isolation of different Salmonella sero-groups B (42.9%), D1and C1 (21.3%) and (21.4%), E1 and type Π (7.1%) were identified. (Table 3)

These indicate the presence and distribution of various serotypes of Salmonella of animal and human origin, which are of significance in the veterinary and public health sectors in Port-said city. The isolation of invasive Salmonella serotypes such as S. Typhimuriumand other pathogenic salmonella in our study indicates the public health significance of these serovars as contaminated chicken meat and meat products may pose health hazards. This risk may further be higher if chicken meat or giblets are consumed undercooked or cross-contamination in the kitchen with Salmonella during meal preparation (Scott, 1996 and Uyttendaele et al., 1998). The risk increases if the drip contains salmonella which may reach to the consumer due to improper handling of these products. The importance of some of the basic instructions regarding storage temperature, cooking and prevention of Salmonella contamination and cross-contamination is not appreciated by many consumers (Scott, 1996 and Uyttendaele et al., 1998). Therefore, efforts should be made to enhance public awareness and consumer education to prevent the horizontal spread of Salmonella. Some of the measures in controlling Salmonella and other foodborne pathogens in the food chain include the introduction of good manufacturing practices (GMP) and hazard analysis critical control point (HACCP) concepts together with stringent control of all aspects of chicken meat production, preparation and distribution (Dawson, 1992). Education of personnel involved in food preparation and microbiological monitoring of broiler chicken and rejection of infected flocks from food production is also required (Arumugaswamy et al., 1995). The high level of contamination of chicken meat and giblets with Salmonella observed in our study indicates the need for an improvement in the microbiological quality of retail chicken. There is also a need for a comprehensive epidemiological study and control of Salmonella contamination at various levels of chicken production and processing plants in Egypt.

It could be concluded that there are different Salmonella serotypes including S. typhimurium,       S. enteritidis, S.virchow, S. anatum and Salmonella type Π circulating in broiler chicken farms in Port said city, Egypt and the most prevalent ones are S.Typhimurium and S.enteritidis.The prevalence of both Salmonella serotypes in our broiler chicken farms constitutes an important problem due to their zoonotic importance and consequently the adverse effect on the human health.

Foodborne illness usually arises from improper handling, preparation, or food storage. Good hygiene practices before, during, and after food preparation can reduce the chances of contracting an illness. There is a consensus in the public health community that regular hand-washing is one of the most effective defenses against the spread of foodborne illness.

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