The Bacteriological Quality and Safety of Bovine and Water Buffalo’s Carcasses Slaughtered in Port-Said Slaughterhouse

Introduction

Bacterial attachment to many surfaces has been studied in a wide range of environments. Bacterial attachment may be beneficial in some cases as waste water treatment and in fermentation technology. However, attachment of bacteria to meat surfaces may delay meat shelf-life and/or constitute a public health hazards.

The microbial quality of carcasses obtained from abattoir can vary greatly. Several highly variable factors influence both the initial contamination and the potential subsequent growth of the bacterial flora. The poor hygiene and sanitation prevailing in the abattoir encourage microbial contamination, their survival and growth. The main cause of the higher initial microbial load on the carcasses is due to traditional floor dressing system and neglect of minimum hygienic requirements.

The meat processing in Port-Said abattoir is bases on traditional method of slaughter in which skinning was started by knife and hand followed by the evisceration on the floor without hanging. Last washing then transport of meat/carcasses to the market without chilling, the procedure of the slaughter line is handwork.

Meat is recognized as one of the most perishable foods. This is due to its chemical composition that favors microbial growth to unacceptable levels contributing significantly to meat deterioration or spoilage (Doulgeraki et al., 2012). The high initial microbial load on the carcass surfaces will be deteriorating the meat to be unappealing and unsuitable for human consumption (Fung, 2010).

Food-borne diseases often occur followed the consumption of meat from infected animals or contaminated carcasses with pathogenic bacteria. Cattle are regarded as the main reservoir for E. coli (Elder et al., 2000). Meat and meat products are still regarded as main vehicles for transmission of this pathogen (Charimba et al., 2012).

Salmonella, a genus within Enterobacteriaceae, remains as an important meat-borne pathogen throughout the world. Consumption of contaminated beef is considered the major source of human salmonella infections and the main cause for salmonellosis outbreaks (Torlak et al., 2012). To date, there is no published study intended for the evaluation of bovine carcasses at Port-Said city. Therefore, the present study was undertaken to evaluate the general bacteriological quality, based on swabbing technique of bovine carcasses slaughtered in Port-Said.

Material and Methods

1. Study Design:

This study was implemented from September 2011 to February 2012 on locally produced bovine carcasses slaughtered (male cattle and buffalo) at Port-Said abattoir. The carcasses were surfaces evaluated directly after processing and just before loading for bacteriological indices. Each carcass (average weight 150kg ±50) was divided into two half, each half represented as one sample, each sample was swabbed from external and internal surfaces. Four swabs were collected from each surface. Data were recorded to detect bacteriological quality of bovine carcasses which slaughtered at Port-Said abattoir and determine the presence of E. coli and salmonella. Bacteriological evaluation and biochemical identification were done in the laboratories of the General Organization for Export and Import Control at Port-Said Governorate.

2. Samples Collection: A total of 784 swabs samples were collected from 49 carcasses of Port-Said abattoir. Each carcass was divided into 2 half, a total of 8 swabs were collected from each half (4 from external surface and 4 from internal surface). The following sites were indicated in accordance with Standard Operating Procedure for Microbiological Examination of Carcasses by Wet/Dry Swabbing. The sampling sites were neck, brisket, flank and rump cuts.

3. Swabs Technique (EC, 2005): Sample swabbing of the carcasses was performed after the completion of carcass dressing and before loading using wet/dry swabbing method by moistening swabs prior to the collection of samples using a test tube contained a 9 ml of sterile Diluents (0.1 % peptone and 0.85% NaCl) for a minimum of five seconds. The swabs are taken from the carcass sample sites by swabbing vertically, horizontally, and diagonally for not less than 20 seconds using a sterile 10 cm² square template and as much pressure as possible. One ml of each diluent was used in preparation of serial dilution and the rest was used as pre-enrichment medium for isolation of salmonella. From the original dilution, 1 ml was transferred aseptically to a test tube containing 9 ml sterile 1% peptone water to prepare dilution of 10^-2, then from which further tenth fold decimal serial dilutions up to 10^-7 were prepared. From these serial dilutions, the bacteriological investigations were performed as follow:

1. Determination of Total Bacterial Counts: The pour plate technique recommended by ISO (2002a) was applied using Standard Plate Count Agar plates incubated at 30°C for 72 ±3 hours.

2. Determination of Total Enterobacteriaceae Counts: The total Enterobacteriaceae counts were determined by the technique recommended by ISO (2004) was applied using Violet Red Bile Glucose agar plates incubated at 37°C for 24 h ± 2 hours.

3. Determination of Total Coliforms Counts: The method described by ISO (2006) was applied using Violet Red Bile Agar with Lactose plates incubate at 35 ± 2°C for 18 – 24 hours.

4. Determination of E. coli Counts: The method described by ISO (2001) was applied using Trypton-Bile-Glucuronic Medium incubated at 44°c for 18 to 24 hours.

5. Incidence of Salmonellae: The technique recommended by ISO (2002b) was applied as using Rappaport-Vassiliadis enrichment broth incubated at 42°C for 24 ± 3 hours. The selective plating was done onto the surface of Xylose Lysine Desoxycholate agar incubated at 37°C for 24 hours.

Results and Discussion

Bacteriological evaluation is one of the most important information that indicating the fitness and safety of any food article (Libby, 1975). Literatures extended over many years were pointed out that bovine meat during slaughtering are liable to contamination with various kinds of microorganisms from different sources.

1. Total Bacterial Counts: It is evident from the microbial evaluation of 49 slaughtered beef carcasses at Port-Said abattoir that the mean values of total bacterial counts of the examined external carcass surfaces ranged from 14x10⁶ to 18x10⁶ cfu/cm² (Table, 1). Neck surface constitutes the highest total bacterial count followed by rump, brisket and flank surfaces.

The mean values of total bacterial counts of the examined internal carcasses surfaces ranged from 10x10⁶ to 24x10⁶ cfu/cm² (Table, 2). Also, neck surface constitutes the highest total bacterial count followed by rump, brisket and flank surfaces.

Meat is regularly contaminated by aerobic bacteria from different sources during processing as hide/skin, floor washings, viscera (intestinal contents), abattoir environment, processing equipment, tools, water, hands, clothing, gum boots, aprons and tables (Buchananand Halbrook, 1995; Rahkio and Korkeala, 1997; McEvoy et al., 2004; Holds et al., 2007 andZweifel et al., 2008).

The means of total bacterial counts of external brisket and flank surfaces were significantly higher than those of internal surfaces of the same sites (Figure, 1). Meanwhile at neck surface, the total bacterial count at internal surfaces was higher than that of external surfaces.

The presence of microorganisms on meat surface and their initial number determines the safety, shelf-life and hygienic quality of meat (Nottingham, 1982; Fung, 1987 and Mackey & Roberts, 1993). The recorded results in the present study are nearly higher than those reported by Sumner et al. (2003); Hutchion et al. (2005); Zweifel et al. (2005) andNouichi & Hamdi (2009).

Unsanitary environmental conditions in food processing plants can occur due to suspended bacterial particles in the air which are microscopic and suspended in the air as an aerosol. This contaminated air comes in contact with food products, containers, equipment and other food contact surfaces during processing (Sutton, 2004).

Total bacterial count remains one of the most useful indicators of the microbiological status of meat. However the Egyptian Organization for Standardization and Quality (EOS, 2005) did not set permissible limit for total bacterial count on the fresh bovine carcass surfaces directly after processing. The high total bacterial count on the surface of any foods often indicates contaminated raw material and/or unsatisfactory sanitation.

2. Total Enterobacteriaceae Counts: Testing for the presence or numbers of total Enterobacteriaceae as marker organisms in foods is widely applied in many food microbiology laboratories. In this study, Enterobacteriaceae were detected in 49 (100%) samples from examined swaps of beef carcass surfaces samples. It is evident from the results that the mean values of Enterobacteriaceae on the examined external carcass surfaces samples were from 38x10⁵ to 61x10⁵ cfu/cm² (Table, 1). The flank constitutes the highest Enterobacteriaceae count followed by neck, brisket and rump.

Enterobacteriaceae is an indicator for fecal contamination of the carcass (Zweifel et al., 2005). Unlike the flank and neck, the brisket and rump has always presented significantly lower levels of contamination by Enterobacteriaceae, this is due to its remote location of soil and the workers manipulation when the carcasses are suspended. The carcasses being constantly suspended, they undergo a shift of germs from posterior to anterior.

Enterobacteriaceae counts from the internal carcasses surfaces ranged mainly from 60x10⁵  to 68x10⁵ cfu/cm² (Table, 2). The obtained results confirmed that flank constitutes the highest total bacterial count followed by neck, brisket then rump. Group of Enterobacteriaceae was even distributed on the internal surface of the carcasses. Samples from external surfaces of cattle carcasses showed no significance difference (P>0.05) with those counts on the internal surfaces of carcass except the rump site which the result showed that it differs significantly (Figure, 2). The recorded results in the present study are lower than those reported by Crowley et al. (2005), meanwhile the data were higher than those recorded by Murray et al.(2001); McEvoy et al. (2004); Hutchison et al.(2005); Zweifel et al. (2005) and Zweifel et al. (2008).

The important factors that determine the microbiological quality of the carcass after getting out from the abattoir are conditions of storage and distribution (Nottingham, 1982).

3. Total Coliforms Counts: The overall occurrence of coliforms in the examined slaughtered cattle was 100%. It is evident from the results that the mean values of coliforms on the examined external carcass surfaces samples ranged from 25x10⁵ to 69x10⁵ cfu/cm² (Table, 1). Flank constitutes the highest total bacterial count followed by brisket, neck and rump.

The high coliforms counts indicated inadequate hygienic measures of meat during slaughtering, cutting and dressing of the carcass due to carcass processing at Port-Said slaughterhouse depend on the traditional method of slaughter which enhance carcass contamination from the floor and other external sources. Both the knives used for slaughtering and cutting as well as contaminated water are important sources of coliforms in meat. The recorded results in the present study are nearly higher than those reported by McEvoy et al. (2000); Dennai et al. (2001); Ware et al. (2001); Zweifel and Stephan (2003); El-Hadef et al. (2005) and Nouichi & Hamdi (2009).

Coliforms count of the examined internal carcass surfaces samples ranged from 27x10⁵ to 66x10⁵cfu/cm² (Table, 2). Neck constitutes the highest coliforms counts followed by brisket, flank and rump.

It is observed that the mean values of coliforms of examined internal neck and flank surfaces samples were significantly differ (P<0.05) than those of the examined external surfaces samples of the same sites (Figure, 3). Meanwhile at brisket and rump surfaces, coliforms count at internal surfaces was not significantly differ (P>0.05) than those of external surfaces of the same sites.

4. Total E. coli Counts:E. coli failed to be isolated from all Port-Said abattoir samples. E. coli is a normal and healthy part of the intestinal microflora of many animals, including humans. However, some strains can cause food-borne illness (Carney et al., 2006).

In contrast, Gill et al. (1996) recorded that contamination of the rump with faecal organisms is much greater than contamination of the brisket, and very much greater than contamination of the neck.

In spite of the limited comparability, the results obtained from beef carcass slaughtered at Port-Said abattoir were differed substantially from those reported by Madden et al.(2001); Carney et al. (2006); Nastasijevic et al. (2009) and Charimba et al. (2012). Cattle are known to carry E. coli but the carcass of carrier animals should be free from the organism unless abattoir practices permit cross-contamination from the hide or visceral content to the carcass (Chapman et al., 1994).

5. Salmonella: The conventional culture-based method used for monitoring of salmonella on 49 carcass surfaces from Port-Said abattoir was failed to recover the pathogens. but a Northern Ireland survey of cattle carcasses (n=200) found 1.5% positive for salmonella Madden et al. (2001). While in Australian domestic meat plants, Vanderlinde et al. (1998) found salmonella on 1.4% (n=144). However, in a major survey of 2168 of steer/heifer carcasses in the USA, 1.5% were positive for salmonella Sofos et al. (1999).

In conclusion, this study is the first of its type in the study area; their data reflect the poor bacteriological quality of bovine carcass surfaces slaughtered at Port-Said abattoir. The surfaces of bovine carcasses have invisible contaminations in which carry a large number of microorganisms. It may limit the opportunities of meat storage and therefore their commercial life; as a result, they accentuate economic risks by loss of foodstuffs, and health risks to public health by meat-borne illness.

Table (1): Mean values of TBC, TEC, TCC and EC of External Carcass Surfaces at Abattoir (n= 49)

±S.E. Standard error of mean

Table (2): Mean values of TBC, TEC, TCC and EC of Internal Carcass Surfaces at Abattoir (n= 49)