Research Article - (2011) Volume 1, Issue 4
Department of Food Technology, Federal Polytechnic, Ado – Ekiti, Nigeria
Ready to eat suya (dried smoked meat) samples were collected from suya processors in four different locations within Ado-Ekiti and Akure, two state capitals in South West, Nigeria. Studies on the microbiological quality of suya was carried out. The moisture contents ranged from 47.80 to 50.00% (Ado) and 46.50 to 52.01% (Akure). The bacteria counts for the samples were 0.30 – 0.4 × 105 cfu/g (Ado) and 0.3 – 0.85 × 105 cfu/g (Akure) while fungi counts; ranged from 0.10 – 0.2 × 105 cfu /g (Ado) and 0.10 – 0.22 × 105 cfu/g (Akure). Fifteen (15) general of microflora were isolated, characterized and identified. The isolated were eight (8) bacteria, four (4) molds and three (3) yeast. The following species recorded maximum percentage occurrence; Staphylococcus, coliforms and Aspergillus spp. The isolation of probable potential pathogens from suya samples analyzed is of public health significance.
Traditionally, processed meat products are produced and consumed in different countries throughout the world (Vilar,et. al., 2000). Suya is a spicy, traditional stick meat product that is commonly produced by the Hausas in Northern Nigeria from beef (Alonge and Hiko 1981). Where rearing of cattles is an important pre – occupation and major source of livelihood for the people (Edema, et. al., 2008). This leads to the production of ready – to – eat beef products such as suya, kilishi, balangu and kundi. suya is however the most popular as its consumption has extended to other part of the country (Inyang et. al., 2005).
It is produced from boneless meat, hung on stick and spiced with peanut cake, salt, vegetable oil and other flavourings followed by roasting around a glowing charcoal fire (Abdullahi, et. al., 2004). Even though meat from freshly slaughtered, healthy animals is supposed to have no, or very low microbial populations, laboratory evidence suggests that they could be contaminated to an unsafe level at the point of consumption (Umoh, 2001). The fact that there are sporadic cases of gastroenteritis and symptoms of food infection after consumptionof suya indicate the products indeed constitute a food safety risk (Odusote and Akinyanju, 2003; Inyang, et. al., 2005). Microbiological quality of suya sold in Akure and Ado-Ekiti State capitals of Ondo and Ekiti States respectively was investigated and reported upon.
Sampling procedure
Samples of suya used in this study were obtained from four suya spots at four locations in Ado and Akure capitals of Ekiti and Ondo States respectively in South-western Nigeria and a total of 32 samples were collected. Four replicate samples were collected from each location. From each of the sites, ready – to – eat suya samples were purchased and transported to the laboratory in sterile bags packed in insulated containers with ice packs. Analyses were carried out within 6hours after sampling. Where immediate microbiological evaluation was to be delayed, the samples were refrigerated at 4°C and analyzed within 24hour of collection (Abdullahi et. al., 2004). All experimental determinations were made in triplicate.
Microbiological analyses
The total viable counts were carried out using Nutrient agar (Oxoid Ltd., Basing Stoke Hants England). Enumeration of fungal counts (Yeast / Mould) was on acidified potato dextrose agar (PDA, Oxoid, UK). In serial dilution preparation, 10.0g of sample was aseptically transferred into 90.0ml of diluted water and homogenized by vortex. Subsequent serial dilutions up to10-5 were made (Kalalou et. Al., 2004). The enumeration of micro organisms in the samples was by the pour plate technique. At the end of the incubation, resultant microbial colonies (bacteria and fungi) were counted.
Discrete bacterial colonies on Nutrient agar (NA) were sub-cultured onto freshly prepared nutrient agar plate by streaking. Fresh PDA plates were used to subculture fungi. Stock culture of the isolates were developed on slants and stored at 10°C with transfers at intervals of 14days (Ojokoh, 2006). Isolates were identified by cultural and morphological characteristics as well as biochemical tests such as the catalase, coagulase amongst others in accordance with the methods of (Cheesbrough 2000).
Determination of moisture content of suya
The moisture content of the suya samples was determined by the methods of AOAC (2004) on dry weight basis.
Statistical analyses
The data generated were subjected to statistical analyses using SPSS 16.0 for windows. Means were separated by Duncan’s Multiple range tests (Steel and Torrie, 1980).
The moisture contents of suya samples evaluated in this study ranged from 47.80 to 51.00% and 46.50 to 57.00% for Ado and Akure respectively as presented in Table 1 and 2. The total viable counts in samples of suya from both towns are presented in Table 1 and 2. the minimum counts obtained from the samples were 0.3 × 105 bacteria, fungi: 0.11 × 105 recorded for Ado samples while 0.31 × 105 fungi were recorded for Akure samples.
Table 1: Microbial counts (105 cfu / g) and moisture contents of suya samples from selected locations in Ado-Ekiti
Table 2: Microbial counts (105 cfu / g) and moisture contents of suya samples from selected locations in Akure
Bacteria general isolated were four each for all the samples from both towns with exception of samples from locations C and K that had five and three each respectively as shown in Table 3 and 4.
Table 3: Micro organisms isolated from Ado-Ekiti samples
Table 4: Micro organisms isolated from Akure samples
The species of mold identified were four while yeast were three. The occurrence of different types of micro organisms in the suya samples analyzed indicated 100% for both Stapholococcus and Aspergillus species as shown in Table 3 and 4.
The moisture contents of suya samples varied from one location to other. The reason for the observed significant differences in moisture contents among the locations is unknown. Bacteria counts for samples from Ado ranged from 0.30 to 0.48 × 105 (cfu/g) and 0.31 to 0.85 × 105 (cfu/g) from Akure samples. Edema et. al., (2008) recorded values for aerobic mesophiles counts in suya samples in the range of 0.07 to 2.22 × 105 (cfu/g). The value recorded in this study is within the range of those of Edema et. al., (2008) but more than 104c fu/g reported by (Osho 2004). However, these values place the suya samples examined in this work in the acceptable but not satisfactory range under the Public Health Laboratory Service guidelines for the bacteriological quality of ready-to-eat foods samples at the point of sale (PHLS, 2000).
E. coli, Salmonella spp. and Klebsiella spp. all coliforms which were isolated from all the samples and the presence of Bacillus spp in some rendered the samples unsatisfactory according to (PHLS 2000). The level of presence of these organisms in food has been described as index of food hygiene (Adesokan et. al., 2008; Jay, 1978).
The presence of Staphylococcus spp. in all the samples could be from nose where it is commonly found, hands, skin and clothing of handlers, since suya processors were found to be illiterate men without formal training in food preparation which is necessary and important for hygienic handling of foods (FAO, 1999). Streptococcus spp, proteus spp and Pseudomonas species were also isolated, an observation in agreement with the findings of (Edema, et. al., 2008). Three species of yeasts were identified: Candida, Saccheromyces and Rhodotorula while molds found were Aspergillus spp, Mucor spp, Penicillium spp and Rhizopus spp. It should also be noted that some species of Asperigillus are known to produce powerful mycotoxins which are harmful to man, thus their occurrence in suya is undesirable. The presence of molds could have come from contaminated spices used and wrapping with contaminated wrap before serving (Shamsudeen and Oyeyi, 2008). Edema et. al., (2008) found that suya are kept at ambient temperature and the re-heating temperature of less than 70°C is not sufficient to destroy all the vegetative cells and heat resistant spores of bacteria especially if the meat is heavily contaminated with enteric bacteria (Bryan, 1988).
There is need for monitoring of this nutrition products by educating processors and consumers on good sanitary practices during processing displaying and sale of the products and the possible danger of contaminated products.
