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Adugna Melkie W/ Medhin
Instructor- Ketema Bacha (PhD)
July 2010
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1. Introduction
2. Objectives
3. Description of Ayib, Unripened traditional cottage
cheese and Ripened cheese
4. Microbiological quality of««««
5. Nutritional constituents of«««
6. Safety of ««««««..
7. Summery and conclusion
8. References
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Cheese
Fermented product of milk, Lactic acid fermentation.
Fermentation is a chemical process by which changes are broughtabout in an organic substrate through the action of enzymeselaborated by micro organisms.
Casein in milk , has functional properties, for coagulation in tocheese product.
The curdling of milk is done by enzyme rennin (casein coagulase) andlactic acid bacterial (LAB) starter culture.
Cheese can be unripened cheese if they are produced by single stepfermentation.
Ripened cheese if additional growth is required during maturation of cheese to achieve the desired taste, texture, and aroma.
Ripening involves additional enzymatic transformations after theformation of cheese curd. .
Cheese may be consumed as fresh curd or it may undergo ripeningby means of enzymes from the milk, from the rennet, and frommicroorganisms in the cheese or on the surface.
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To describe the process how Ayib, traditional Ethiopian cottage
cheese, is produced.
To describe What ripened cheese is and the major cheese groups.
To Identify the microbial quality of Ayib and Ripened cheese.
To describe the effect of curd cooking temperature on the microbial
quality of Ayib.
To assess the safety and nutritional quality of Ayib and ripened
cheeses.
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How is Ayib, Produced in Ethiopia?
Fumigating the clay pot with leaves or stem of Olea spp. (woyira) Raw milk is collected in a clay pot and kept in a warm place, about
30oc for 1-3 days to sour (to form sour milk)
Churning of sour milk is carried out by slowly shaking the contents of the pot until the fat is separated
The fat is removed then defatted milk (Arrera) is formed
The defatted milk is heated to about 50
o
c-70
o
c until a distinct curdmass forms and floats over the whey (aguat)
After gradual cooling, the curd is recovered from the whey
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Kibe (traditional
Butter)
Fresh Cows· Milk
Keep in warm place
(30oc)
Churning
Ayib (traditional
cottage cheese)
Arrera (defatted
Butter milk)
Whey (Aguat)
Ergo (Sour milk)
Cooking
(heat about 50oc-70oc)
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Clay pot
Muslin cloth
Wood stick
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Ripening is the process of allowing change of cheese by enzymes and
microorganisms which is important for development of characteristic
flavor, consistency, and appearance.
The effects of the enzymes and the microorganisms depend
On pH and temperature
On the content of moisture and of salt
on the surface treatment.
Ripening period varies from a few weeks up to several years
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Cheeses can be classified as
Soft cheeses (high, 50-80%, water content)
Unripened (fresh cheeses)= Cottage, Quark, Cream, Mozzarella
Ripened= Camembert, Brie, caciota
Pickled or salt-cured= Eeta, Domiati Semisoft cheeses (39-50%, water content)=Pressed cheeses
Ripened principally by internal mould growth= Danish Blue
Ripened by bacteria and surface micro-organisms= Limburger
Ripened primarily by bacteria= Edam, Gouda, Brick, pasta filata
Hard cheeses (low water content, less than 39%) =Pressed cheeses
Ripened by bacteria , with out eyes= Cheddar,Caciocavallo
Ripened by bacteria, with eyes= Emmental , Gruyere
Very hard cheeses (water content less than 34%)= Pressed cheeses
Asiago old, Romano, Grana, Parmesan
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Ayib [ 100 samples from open market in Awassa, Ethiopia]
The counts of mesophilic bacteria, yeasts and entrococci of 108, 107,
and 107 cfu/gm respectively .
Bacillus cereus, and Staphylococcus aureus were isolated at varying
frequencies built at low temperature (102 _103cfu/gm).
The PH values of the samples varied between 3.3 and 4.6 with about
40% having PH lower than 3.7.
The high microbial in the Ayib would come from handlers and plant
parts used for packaging and for importing flavor.
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The effect of curd cooking temperature on themicrobial quality of Ayib
Ayib is made by cooking defatted sour milk at 40oc-70oc
Cooking at 40
OCdid not decrease the microbial load in general .
At 50OC, counts of Entrococci, Entrobacteriacea and Staphylococcidecrease to102 cfu/gm. However substantial number of yeasts, moldsand lactic acid bacteria still remained in the product.
Cooking at 60OC markedly decreased number of most bacteriagroups, yeasts and molds.
Heat treatment at 70 OC required a relatively shorter time for curd
formation and achieved maximum reduction in number of variousmicrobial groups .
Temperature higher than 800C are reported to give the product acooked flavor.
heat precipitation of curd at 700C (PH, 4.0) was recommended as it is
resulted in a less contaminated and more wholesome Ayib .
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Ripened Cheese
The combined effects of moderately low pH and low Eh provide a
barrier against some microorganisms, there are others, including
spoilage organisms, and in rare cases, pathogens, that can grow
in the cheese environment.
Microorganisms can cause several general types of spoilage in
cheese. these include appearance defects, texture defects, and
flavor and aroma defects.
Spoilage of cheese by microorganisms is a constant concern, the
presence of pathogens in cheese occurs only infrequently, and
rarely does food borne disease result.
Just a single positive test for L. monocytogenes or E . coli
O157:H7 may initiate a product recall.
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Type of nutrient in Ayib Percentage composition
Water««««««««««««««««««..79
Protein«««««««««««««««««..14.7
Fat««««««««««««««..««««««.1.8
Ash«««««««««««««««««««««.0.9
Soluble milk constituents«««««.««.3.1
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Milk Cheese Whey
(100kg) (10.8 kg) (89.2kg)
Water 87 3.9 83.1
Fat 4 3.6 0.4
Total Protein 3.3 2.5 0.8 Casein 2.5 2.4 0.1
Whey protein 0.8 0.1 0.7
Lactose 5 0.2 4.8
Minerals 0.7 0.6 0.1
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Why cheese Making is important ?
The fresh curd contains valuable nutrients and can therefore quickly
be spoiled by bacteria, Yeasts and molds if not preserved
Cheese making is the means of conserving many of the nutrients in
milk
The main factors contributing to preservation are low Moisture
content (concentration), acidification by adventitious or added lactic
acid bacteria, and salting.
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Ayib
Listeria monocytogenes was not encountered in any of the samples.
Salmonella typhimurium, Salmonella enteritidis and Salmonella
infantis were able to grow when added to raw cheese milk, but none
was able to survive the heating process at the prevailing low pH.
The count of E. coli 0157:H7 increased during milk souring for Ayib
processing, but the count immediately after curd-cooking was below
detectable limits.
LAB suppresses the growth of other micro-organisms.
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Ripened cheese
more focus on emerging pathogens such as Listeria and E. coli
H7:O157
the larger batch sizes increase risk to larger numbers of consumers,
if pathogens are present
Because of the large batches, economic losses will be substantial if
the quality is not acceptable
An unacceptable quality in just a few batches from a producer may
lead to loss of market shares.
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In order to control the presence and growth of pathogenic
microorganisms, it is important to do whatever is possible to prevent
their occurrence from farm to cheese product.
Implementation of HACCP is an excellent tool to control the
pathogens or spoilage microorganism.
Raw milk should be of good quality, and its storage should be at lowtemperatures, especially if storage times are long..
The activity of the starter must be high; this will lead to a fast drop in
pH, helping to control pathogens. If possible, the temperature should
be kept as low as possible and the salt content as high as possible.
To make the cheese is a well-conserved system, creating a protective
chain of hurdles against pathogenic and spoilage microorganisms. Cheese is the wise use nutrients found in milk.
Ayib is a fermented traditional milk product in Ethiopia.
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Almaz Gonfa, Foster, H.A. and Holzapfel, W.H. (2001). Field Surveyand literature review on traditional fermented milk products of Ethiopia. Int. J. of food microbial. 68:173-186
Edward R. Farnsworth (2006) Hand book of fermented functionalfoods. Second edition 8: 245-249
Fekadu B and Abrahamsen R K 1994 Present situation and futureaspects of milk production, milk handling and processing of dairyproducts in Southern Ethiopia. Farm-made milk products in SouthernEthiopia: 1. Chemical and microbial quality. PhD thesis. Departmentof Food Science. Agricultural University of Norway. Norway, pp. 1-16.
James M. Jay, 2000. M odern food microbiology, six edition. Aspenpublishers. Inc. Gaithersburg, Maryland
Marcel Dekker. (2004). Hand book of food and beverage FermentationTechnology 19: 8-9
Mekonnen Tsegaye and Mogessie Ashenafi. (2005) Fate of escherchiacoli 0157:H7 during the processing of Ergo and Ayib, traditionalEthiopian Dairy Products and effect of product storage temperatureson its survival. Int. J. Food Microbiol. 103:11-21
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Mogessie Ashenafi,(1989),Proteolytic, lipolitic and fermentativeproperties of yeasts isolated from µayib¶, a traditiona Ethiopiancottage cheese. SINET: Ethiop. J. Sci. 12:131-139
Mogessie Ashenafi, (1990 )́; M icrobiological Quality of Ayib, atraditional Ethiopian cottage cheese. International Journal of FoodMicrobiology .10:263-268
Mogessie Ashenafi 1990; Effect of curd cooking temperatures on themicrobiological quality of Ayib, a traditional Ethiopian cottagecheese .World Journal of Microbiology and Biotechnology
Mogessie ashenafi, (1994 a) T he aerobic micro-flora and lactic aid bacteria of market Ayib. Ethiopian. J. Art. Sci 14:104-111
Mogessie Ashenafi, (2002). T he microbiology of indigenousFermented foods and Beverages of Ethiopia. A review SINE T PP. 189-245
Mohammed Abdella, Becker, H. and Terplan, G. (1996).comparativestudy on the detection of salmonellae in Ethiopian cottage cheese(ayib) using different culture methods. Arch. Lebensmittelhyg. 47: 83-90
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M.R. Adams and M.O. Moss (1999). Food Microbiology, Third edition,published by the royal society of chemistry, pp. 269
O¶Mahony, F. (1998).R ural Dairy T echnology Experience in EthiopiaI LC A. M anual, 4.International Livestock Center for Africa, Addis Ababa
Reda T 1998 Milk processing and marketing options for rural small-scale producers. In: Proceedings, 6th National Conference of the
Ethiopian Society of Animal Production, May,1997, Addis Ababa,Ethiopia, pp. 61-67.
Robert W. Hutkins (2006), Microbiology and technology of Fermentedfoods, first edition, 5: 211-213
walstra P, Geurts T J, Omen A, Jellema D, Van Boekel M A J S 1999Dairy Technology: Principles of milk properties and processes,Marcel Dekker, INC. New York, Basel.
Yilma Z (1999) Smallholder milk production systems and processing
techniques in the central highlands of Ethiopia. MSc Thesis, SwedishUniversity Agricultural Sciences. Uppsala, Sweden, 67-68.
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