QUALITY CHARACTERISTICS AND MICROBIAL STATUS OF BEEF SMOKED WITH DIFFERENT PLANT MATERIALS AND SUYA PRODUCED FROM ROUND MUSCLES

Description

ABSTRACT
Two experiments were conducted. The first evaluated beef smoked using different plant materials (Acacia raddiana, Eucalyptus camaldutensis, Azadirachta indica and Cocos nucifera) as source of smoke. The effect of the plant materials on the organoleptic, microbial and physicochemical properties of smoked beef was evaluated. In the second study, Suya was produced from various round muscles (Rectus femoris, Semi-tendinosus, Biceps-femoris, Semi membranosus and Vastus lateralis) and evaluated for organoleptic, microbial andphysicochemical properties. Both studies were carried out in a completely randomized design. The result showed that there was no significant (P>0.05) difference among sources of fuel wood tested on the overall acceptability of smoked meat. However, organoleptic scores on a five point hedonic scale were lowest (2.50) for beef smoked with C. nuciferaand highest (3.30) for beef smoked with A. raddiana (Standard check). The pH values were within the accepted limit (5.5-6.5). Percentage thermal shortening were not significantly (P>0.05) different. Percentage Water holding capacity was highest (13.6) in beef smoked with C. nucifera. Total viable counts/ Aerobic plate count, coli-form counts were all within satisfactory limits (i.e. <½ million/g). In the second study, the fat content was not significantly (P>0.05) affected by the muscle types. The score for overall acceptability indicated that the consumers preferred Biceps femoris which was significantly (P< 0.05) different from other round muscles. Water holding capacity was observed to have influence on other qualities such as the flavour, juiciness and tenderness. Product yield was lowest (70.20 %) in Vastus lateralis, indicating a good yield from all muscles. Microbial load of all suya samples fell within satisfactory limit with reference to the standard microbial load specification (i.e. <½ million/g). It was concluded that Eucalyptus camaldutensis (Turare), Azadirachta indica (Neem) and Cocos nucifera (coconut shell) are good sources of fuel woodand can be used as an alternative to Acacia raddiana for smoking beef. Furthermore, smoke had an antimicrobial and antioxidant effects as the microbial load were all within satisfactory limit. From the results of the second study, it was concluded that the prime cuts, apart from resulting in Suya with high prices are not necessarily better than Suya from less choice parts of the carcass (Semi-membranous, Semi-tendinosus, Biceps femoris, Rectus femoris and Vastus lateralis) in terms of product yield and eating qualities.

CHAPTER ONE
1.0 INTRODUCTION
Meat has been defined as the flesh of animals which is suitable as food. Meat makes a valuable contribution to diets because of its high biological value and an excellent source of amino acids, vitamins and minerals (CAST, 1997). A daily intake of 100 g of meat can supply up to 50% of the recommended daily allowance for Iron, Zinc, Selenium, Vitamins B1, B2, B6, B12 and 100% of vitamin A (Biesalski and Nohr, 2009).
In Nigeria there is a preferential consumption of different types of meat by communities due to a combination of factors bordering on religious belief, culture, food habits, sex of animal, age at slaughter, socio-economic factors and individual variation (Ajiboye et al., 2011).
Meat being nutritious with high moisture content and nearly neutral pH is a good culture medium for many micro-organisms (bacteria, yeasts and moulds) and as such, classified among perishable foods whose contamination with spoilage organisms are almost unavoidable (Ikeme, 1990). This makes meat preservation more difficult than other types of food as it may result in oxidative rancidity, discolouration, off flavour, sliminess etc. The kind and amount of spoilage organisms in meat depends upon the availability of nutrients, presence of oxygen, temperature, pH at storage and generation interval of the spoilage microorganism under given environment etc. (Forrest et al., 2001). It is necessary to minimize deterioration in order to prolong the time during which acceptable levels of quality are maintained. This depends upon the processing and preservative method used and the inherent properties of the meat in question (Forrest et al., 2001).