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BACTERIAL CONTAMINATION AND PREVALENCE OF SOME FOODBORNE PATHOGENS IN EDIBLE BOVINE OFFAL IN ASSIUT CITY

ABD-EL-MALEK, A.M. and EL-KHATEIB, T.

Department of Food Hygiene (Meat Hygiene), Faculty of Veterinary Medicine, AssiutUniversity, Assiut, Egypt

Received: 18October 2016;       Accepted: 21November2016

INTRODUCTION

Edible bovine by-products (offal) have recently received significant attention worldwide (Im et al., 2016). In Egypt, edible bovine by-products such as Tripe, Mombar (Intestine), Lung and Cerebrum (Brain) are more popular, less expensive and have high nutritive value for consumers. They have a good nutritional value due to the high protein and low fat levels as well as good content in vitamins and minerals (Anderson, 1988). Nowadays, Salmonella is one of the most pathogenic genera implicated in food-borne bacterial outbreaks and diseases and that constitute an important public health problem. There are numerous transmission routes for Salmonellosis, but the majority of the human infections are derived from consumption of contaminated foods especially those of animal origin (Saha et al., 2016). Also, B. cereus was identified as a causative agent in 19 % of foodborne outbreaks. The majority of these outbreaks were traced back to rice (50 %) and meat (24 %) (Bennet et al., 2013). 

Numerous studies have described the numbers and types of  bacteria  on  fresh  meats.  Whereas,  studies

Corresponding author: Dr. ABD-EL-MALEK, A.M.

E-mail address: ashraf_702001@yahoo.com

Present address: Department of Food Hygiene (Meat Hygiene), Faculty of Veterinary Medicine, AssiutUniversity, Assiut, Egypt.

evaluating the microbial contamination of diverse edible offal and specifically investigating contamination by pathogens that cause foodborne illnesses are rare. Moreover, there is scarce of the published information about the prevalence of Salmonella spp. and B. cereus in edible bovine by-products obtained from retail butcher's shops in Assiut city. Such microbial contamination of edible bovine by-products may lead to public health problems. Therefore, the main objectives of this study were to enumerate total viable bacterial count, total coliform count and total Bacillus cereus count and determine the presence of Salmonella spp. and B. cereus on some edible bovine by-products commonly consumed in Assiut city, Egypt.

MATERIALS AND METHODS

1. Samples collection:

A total of 150 samples of edible bovine by-products including 40 samples of Tripe, 40 samples of Mombar (Intestine), 40 samples of Lung and 30 samples of Cerebrum (Brain) were collected from different butcher's shops in Assiut city. Each sample was obtained in separate sterile plastic bag. The collected samples were transferred directly to the laboratory where they were prepared for bacteriological examination.

2. Samples preparation:

At the laboratory, each sample was aseptically and carefully freed from it's plastic bag and cut into fine particles by sterile scissor, then homogenized and thoroughly mixed. The fat and adhering extraneous materials on the surface of tripe were removed by knife and it was cut into small chunks of about 2.5 cm (Anna Anandh, 2004).

3. Bacteriological analysis:

3.1- Total viable bacterial count: (ISO protocol, 2003).

3.2- Total coliform count:  (ISO protocol, 2006).

3.3- Count and isolation of B. cereus: (BAM, 2012).

3.4- Isolation of Salmonella spp: Identification of presumptive colonies by biochemical reactions (ISO protocol, 2002). Serological identification of Salmonellae was carried out according to Kauffman – White scheme (Kauffman, 1974)for the determination of Somatic (O) and Flagellar (H) antigens using Salmonella antisera (Denka Seiken Co., Japan).

RESULTS

Table 1: Statistical values of total viable bacterial count (CFU/g) of examined samples of edible bovine by-products.

*Lower than Egyptian standards contamination load (ES, 2005).

Table 2: Statistical values of total coliform count (MPN/g) of examined samples of edible bovine by-products.

*Higher than Egyptian standards contamination load (ES, 2005).

 Table 3:  Incidence of Salmonella spp. in examined samples of edible bovine by-products.

Table 4:Incidence and mean values of positive B. cereus from examined samples of edible bovine by-products.

DISCUSSION

The obtained results in Table (1) indicated that the mean values of T.V.B.C. of total 150 examined samples of edible bovine by-products was ranged from 2x10⁵ to 8x10⁴CFU/g which were lower than standards contamination load set by Egyptian Standards (ES, 2005). Meanwhile, other investigators such as Isabel-Legarreta (2011) recorded lower results. In addition, the finding in Table (1) indicated that the mean number of T.V.B.C. of examined samples of Mombar was 1x10⁵ CFU/g, lower results were reported by Mboto et al. (2012) who found that the bacterial count of Mombar samples was 1x10³ CFU/g. The results also showed that mean values of T.B.C. of examined samples of Mombar was 1x10⁵, of lung was 10⁵ and of Cerebrum was 8x10⁴ log CFU/g, Ahmed and Sarangi (2013) obtained nearly similar results as our findings.

According to the safe permissible limit stipulated by Egyptian Standards limits (ES, 2005) for total coliform count in edible offal (not exceed 10² CFU/gm), it was indicated that 90 of the examined samples of edible offal (32 Tripe, 29 Mombar, 16 Lung and 13 Cerebrum) were accordingly unaccepted (Table 2). These obtained results were in agreement with other studies as Selvan et al. (2007) who recorded higher results of coliform count (1x10⁵ CFU/g).

From the achieved results illustrated in Table (3), it could be concluded that 4 samples were positive for Salmonella spp. with overall percentage of 2.7%. Three samples of lung contaminated with Salmonella (two samples were classified as S. Enteritidis and one sample was identified as S. Typhimurium). Moreover, one sample was categorized as S. Anatum in Mombar. These results might be occurred due to faulty rupture of gastrointestinal tract during slaughtering process which regarded as one of the most important sources of carcass and organ contamination with Salmonella at abattoirs (Stopforth et al., 2006).

The results demonstrated in Table (3) revealed that the Salmonella spp. failed to be isolated from Tripe and Cerebrum samples, this finding was disagree with the results recorded by Akkaya et al. (2012), who found Salmonella in these organs. On the other hand, higher overall Salmonella prevalence (7.1%) in cattle offal were reported by Im et al. (2016).

The obtained data outlined in Table (4) showed that there were 12 samples were positive for B. cereus (5 tripe, 4 Mombar and 3 Cerebrum samples) and these numbers represent 8% of total number of samples. The mean number of B. cereus in Tripe samples was 3x10³ CFU/g and Mombar samples was 1.4x10³ CFU/g while in Cerebrum samples was 5x10² CFU/g. From Table (4) it was obvious that the mean number of overall count of B. cereus in this study was 1.6x10³ CFU/g. This value were below the pathogenic number of B. cereus which estimated as 10⁴ CFU/g (Lee et al., 2006). This obtained result was disagree with a related study conducted by Iroha et al. (2011), who found lower incidence of B. cereus (2%) from 100 samples of beef meat included lung and Cerebrum samples and other internal organs.

CONCLUSION AND RECOMMENDATIONS

The achieved results in the present study indicated that total coliform count of the edible bovine offal samples were higher than the permissible limits and the most common Salmonella serotypes isolated were S. Enteritidis and S. Typhimurium so the presence of such food poisoning microorganisms may pose potential risk for public health. It is recommended that hygiene improvements are needed in the establishments selling edible bovine by-products to protect public health.

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