CHAPTER
ONE
1.0 INTRODUCTION
Dairy products are
various products derived from cow’s milk or that of other female mammals such
as goat, sheep, yaks, horses, camel. Dairy products include yoghurt, nono (fermented
cow’s milk, madara (unfermented cow’s milk, cheese, whey, condensed and
evaporated milk.) (cultureforhealth, 2015).
Yoghurt, nono, Madara
has become so highly valued in humans diet because of their nutritional values
and their culinary possibilities (George and pamplon, 2006) Yoghurt is made by controlled thermoduric fermentation of
pasteurized non-fat or low fat milk carried out around 45% (Prescott et al., 2005) . It is probably the most
popular fermented milk in Nigeria. Yoghurt is a foods produced by bacterial
fermentation of milk and these bacteria are known as “yoghurt cultures. Fermentation
of lactose by these bacteria produces lactic acid which acts on milk and
protein to give yoghurt its texture and characteristic tang. Also yoghurt is
made by inoculating certain bacteria (starter culture) usually Streptococcus thermopiles and Lactobacillus bulgaricus into milk,
after inoculation, the milk is incubated at 40 to 46% (105 to 115%) until
fermentation, the milk is coagulated by bacteria to produce lactic acid (serre
et al., 2009)
Nono is an opaque white to milky
coloured, liquid food drink gotten from fermented raw cow milk made locally (Godwin
and Emmanuel, 2013). It is widely consumed
in many African countries including Nigeria. Nono is of two types such as
kindirimo and sallah though the nono is mostly termed kindirimo. Mostly the
Fulani’s produce milk locally in Nigeria and the excess of the milk is
processed into these products for preservation and use (Akinyele, et al., 1999). Also kindirimo is
produced locally by pasteurized cow milk which are prepared by heating to
boiling and then allowed to cool at 37c and the milk butter from the previous
day is added to it at the rate of 0.5-1% of the amount of milk to be processed
and then left overnight to become sour until it coagulate (Odunfa, et al., 1988)
Madara is the
unfermented raw milk collected from cow’s
under while nono is product form raw Milk collected from cow’s udder
into a container called calabash and allowed to ferment naturally for 24hours. Nono
is also more popular in term of public consumption than madara, this is because
madara is rarely sold to public for direct consumption as compared to nono. Madara
is produced in homes especially in villages where producers are ignorant of shelf-life
and safety standards of the products nono is sold to both rural and urban
dwellers as food (Uzeh, et al. 2006).
1.1 STATEMENT OF PROBLEM
Milk is a highly
nutritious food that serves as an excellent growth medium for a wide range of
microorganism. Milk and its’ derivatives are considered vehicle of Staphylococcus aureus for human
infections and enteropathogenic Escherichia
coli. The microbiological quality of milk and dairy products is influenced
by the initial flora of raw milk, the processing conditions and post –heat
treatment contamination. Undesirable microbes can cause spoilage of dairy
products including Gram-negative psychrotrophs, coliforms, lactic acid
bacteria, yeast and moulds. Of concern to public health is the contamination of
these dairy products by enterotoxigenic strains of staphylococcus aureus and
strains of diarrheagenic Escherichia coli
in these dairy products. For this purpose emphasis will be laid on Staphylococcus aureus and Escherichia coli contamination in some
diary product and to provide safety measure as a result of poor hygiene
practiced by handlers of these products.There is a misnomer in the condition
surrounding the sale of some dairy products such as yoghurt, Nono, madara in
Makurdi Metropolis. Vendors carry the products from manufacturers without
making provision for maintenances of appropriate temperature and sanitary
control. This predisposes these products to post production contamination which
poses danger to public health.
1.2
JUSTIFICTION
Since dairy products are widely consumed as food, this study
will help to establish contamination by Staphylococcus
aureus and Escherichia coli, mode of
contamination and thus aid in determining their safety for consumption. The
result of this study will also help in providing information on these products
by the producers, which will promote healthier handling of the product by the
producers, the sellers and the consumers. It will also reveal the health
implication of their consumption, since they are very delicious and nutritious
drink
1.3 AIM
AND OBJECTIVES OF THE STUDY
AIM
Investigating the
presence of Staphylococcus aureus and
Escherichia coli in dairy products.
OBJECTIVES
1. To isolate and identify Staphylococcus aureus and Escherichia coli present in Yoghurt,
Nono and Madara.
2. To determine the most predominant of
the above mentioned organisms in Yoghut, Nono and Madara.
3. To determine the antimicrobial susceptibility
of the above isolated organisms.