ÖZET

STARTER KÜLTÜR (SAF KÜLTÜR) ÜRETİM İŞLETMESİ DİZAYNI VE FİZİBİLİTE RAPORU

GÜVEN, Mustafa N.

Yüksek Lisans Tezi, Süt Teknolojisi Bölümü
Tez Yöneticisi: Prof. Dr. Sevda KILIÇ
Haziran, 2008, 82 sayfa

Türkiye’de henüz saf kültür üretimi gerçekleştirilmediğinden süt sanayi ihtiyaç duyduğu toplam kültürü bugün tamamen birkaç ithalatçı firmanın aracılığıyla temin etmektedir. Ancak mevcut kültürlerin, Türk halkının damak zevkine hitap eden ürünlerin elde edilmesine pek de uygun değildir ve aynı zamanda saf kültürlerin yurtdışından ithal edilmesinden dolayı ülke ekonomisi de zarar görmektedir. İnsan beslenmesinde çok önemli rolü olan süt ürünlerinin yapımında kullanılan saf kültürü kendi ülkemizde üreterek ithal yolla temin edilen bu kültürler için ödenen dövizin en azından bir kısmının yurtdışına çıkmasını engellemek gerekir. Bunun için çok geniş ve önemli bir bakteri popülasyonuna sahip olan ülkemiz mikroflorasından faydalanarak damak tadına hitap edecek özelliklere sahip kültürlerin hazırlanması gerekmektedir. Bu çalışmada, öncelikle, süt ürünleri üretiminde kullanılan saf kültürler hakkında bilgiler ve üretim yöntemleri, ardından, saf kültür üretim işletmesi dizaynı ve fizibilite raporu oluşturmak için yapılan hesaplamalara yer verilmiştir.

Anahtar Kelimeler: Saf (Starter) Kültür, Laktik Asit Bakterileri, Fermente Süt Ürünleri, Fizibilite

ABSTRACT

THE FEASIBILITY REPORT AND DESIGN OF STARTER CULTURE PRODUCTION PLANT

GÜVEN, Mustafa N.
MSc in Dairy Technology
Supervisor: Prof. Dr. Sevda KILIÇ
June, 2008, 82 pages

As starter culture production has not been able to be realised in Turkey, dairy industry today provides the required total culture through some importer companies. However the available cultures are not suitable to produce the products for the Turkish taste and at the same time the national economy is harmed by the import of the starter cultures. By producing the starter cultures that are very important for human nutrition in our own country, at least some part of the foreign exchange paid for these imported cultures could be kept in hand. To realise this, our country that has a very large and important bacteria population, has to prepare the cultures suitable for the Turkish taste by using microfloration. In this study, firstly, information about starter cultures used in diary production and production methods and secondly, calculations made on the design and feasibility report of the starter culture production plant have been included.

Key Words: (Starter) culture, lactic acid bacterias, fermentated dairy, feasibility

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Kaynak: http://www.acikerisim.ege.edu.tr:8081/jspui/bitstream/11454/3445/1/mustafanguven2008.pdf

Cheese making

Introduction

• Cheese is a generic term for a diverse group of milk- based food products. Cheese is produced throughout the world in wide-ranging flavours, textures, and forms.

• Cheese consists of proteins and fat from milk, usually the milk of
cows, buffalo, goats, or sheep. It is produced by coagulation of the milk protein casein.

Objective of cheese making

 To obtain the optimum cheese composition with respect to moisture, acidity (pH), fat, protein and minerals (especially calcium)

 Establish the correct structure of the cheese at the microscopic level; and

 Ripen to perfection. Grouped according to texture and basic manufacturing procedures there are seven families of cheese.

First Step
• Milk from the evening milking is allowed to stand overnight. By natural processes, this milk will have partially separated during its overnight standing period. The cream is skimmed off, and the partially skimmed milk is combined with whole milk from the morning milking.

Second Step
The milk is gradually heated to 30 to 35 C (86 to 95 F) before acidification and coagulation.

Step 3

• Acidification: Starter culture is added to milk to change lactose (milk sugar) into lactic acid. This process changes the acidity level of the milk and begins the process of turning milk from a liquid into a solid.

Starter culture

• Fermentation starters (called simply starters within the corresponding context) are preparations to assist the beginning of the fermentation process in preparation of various foods and fermented drinks. A starter culture is a microbiological culture which actually performs fermentation.

Step 4

Coagulation: Rennet is added to further encourage the milk to solidify , forming a custard -like mass. rennet

• .Rennet An enzyme used to coagulate milk during the cheese making process. Rennet is derived from one of four sources: the stomach lining of a young calf (the enzyme rennin is found in the stomach lining of animals because it aids in the digestion of their mother’s milk)

• plants (typically thistle)

• microbes in fungus and yeast

• Genetically engineered rennet that imitates animal rennet.

Step 4

Cutting:- It’s then cut into small pieces to begin the process of separating the liquid (whey) from the milk solids (curds).Large curds are cooked at lower temperatures , yielding softer cheeses like Mascarpone and Ricotta. Curds cut smaller are cooked at higher temperatures, yielding harder cheeses like Gruyere and Romano

Step 5

Stirring, Heating & Draining:- Cheese makers cook and stir the curds and whey until the desired temperature and firmness of the curd is achieved. The whey is then drained off, leaving a tightly formed curd.

Here you can see the cheese maker taking some of the whey out of the vat.

Step 6

• Salting: Salt adds flavour and also acts as a preservative so the
cheese does not spoil during long months or years of ageing. It also
helps a natural rind to form on the cheese. There are several ways to use salt. Salt can be added directly into the curd as the cheese is
being made. The outside of the wheel of cheese can be rubbed with salt or with a damp cloth that has been soaked in brine. The cheese
can also be bathed directly in vat of brine. Concentrated brine. adding the salt directly into the drained curd

Step 7

 Curd Transformation
Different handling techniques and salting affect how the curd is transformed into the many cheese varieties made.

• Shaping:

Step 8

The cheese is put into a basket or a mold to form it into a specific shape. During this process, the cheese is also pressed with weights or a machine to expel any remaining liquid. Pressing determines the characteristic shape of the cheese and helps complete the curd formation. Most cheeses are pressed in three to 12 hours, depending on their size.

Step 9

Ripening: Referred to as affinage, this process ages cheese until it
reaches optimal ripeness. During this process, the temperature and humidity of the cave or room where the cheese ages is closely monitored. For some cheeses, ambient molds in the air give the cheese a distinct flavour. For others, mold is introduced by spraying it on the cheese (brie) or injecting it into the cheese (blue cheese). Some cheeses must be turned, some must be brushed with oil, and some must be washed with brine or alcohol.

Aging should take place in a controlled environment. Different cheeses required different temperatures and humidity’s, however in a small refrigerator temperature is kept at 55°F and 85% humidity. During aging , the cheese should be rotated or flipped periodically to prevent moisture from settling in the cheese and to prevent an inconsistent internal consistency.

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Meat fermentation is a biological process that preserves the meat and provides distinct properties such as flavor and tenderness.

Traditionally, fermentation relied on the natural microbial load of the meat but, in modern production, a selected microbial culture is added.

During the fermentation process, fermentable sugars (dextrose or fructose) that are present in the meat or added by the manufacturer are transformed into an acid, called lactic acid.

The formation of lactic acid in the product leads to an increase in acidity. The more acidic the meat product is the lower the pH will be.

The pH of fresh meat is approximately 5.6-5.8. The pH of fermented meat is usually below 5.3.

Besides lactic acid, there are a variety of other products that are formed during the fermentation process. These include organic acids, carbon dioxide and alcohols that give the fermented products distinct flavor and texture.

Starter culture:

For many years, sausages have been inoculated with a concentrated and selected mixture of bacteria, called starter culture or inoculums, to begin fermentation. The use of starter cultures means that the proper type of bacteria in the amount required is added to the sausage emulsion to ensure efficient and safe fermentation.

There are two species of bacteria that are primarily responsible for converting sugars into lactic acid:

· Lactobacilli spp used in slow fermentation processes

· Pediococci spp used in rapid fermentation processes

(In Europe, as well as in Turkey, these genera are most often used in combination with micrococci and staphylococci.)

Depending on their pH and aw levels, raw fermented sausages are classified as: semi-dry sausages and dry sausages.

Semi-dry sausages:

Semi-dry (quickly fermented) sausages differ greatly from dry sausages by their “tangy” flavor resulting in lactic acid accumulation. Semidry sausages are usually stuffed in medium and large diameter natural or artificial casings.

The length of production (smoking and fermentation) of these sausages depends on their type, but rarely exceeds several days.

The pH of semidry sausages is clearly acid; 4.8 to 5.4.

Semidry sausages are regularly smoked and only exceptionally slightly cooked by the heat applied in the smokehouse at various temperatures, mostly not exceeding 45°C and sometimes raising to 60°C. After smoking the sausages are usually air-dried for a relatively short time.

Semidry sausages usually contain an important proportion of beef meat. Their shelf life is surprisingly good due to low water activity. Semidry sausages have improved stability if stored in the chiller, protected from humidity rather than at room temperature.

Dry-fermented sausages:

Properties of dry (slow-fermented) sausages depend not only on the bacterial fermentation, but are also strongly influenced by biochemical and physical changes occurring during the long drying or ageing process.

The length of production, either with or without smoking, and drying periods depends on some factors; such as diameter and physical properties of casings, sausage formulation, choice and methods of preparing meat, conditions of drying etc., but overall processing time require up to 90 days.

The final pH of dry sausages is usually between 5.0-5.5. It increases during the second part of this long ageing process.

Dry sausages are made from selected, mainly coarsely chopped, meat. Their water content is under 50% for sucuk and 35% for other dry sausages.

Some of dry sausages are subjected to cold smoking (12 to18°), but sometimes not; in some countries they are often heavily spiced with red pepper or garlic or heavily smoked and strongly salted.

The formulation, degree of grinding, level of fermentation, smoking intensity, temperature of ageing and type and size of casing as well as other factors determine the properties of the final product.

In the preparation of dry sausages natural casings are preferred because they adhere closely to the sausages as sausages shrink.

The shelf life of dry sausages is excellent, which may be especially attributed to the high salt-to-moisture ratio. These sausages are normally kept without refrigeration.

Raw sausages, which are not submitted to the smoking process, are known as air-dried sausages.

The principle of dry sausages is salami of different types produced in many countries as small-diameter dry sausages. Dry sausages may be hard, intended for slicing and soft style sausages, which can be spread.

Selection of raw materials

Chilling of meat and fat (0 to 7˚C.)

Comminution and blending of meat and fat

(bowl chopper or mincer and vacuum mixer)

Addition of spices and curing salt

(as well as carbohydrate and starter culture if applicable)

Blending

Air removal (vacuum chopper or vacuum mixing)

Stuffing (vacuum stuffer)

Drying of surface of sausage

Smoking (if applicable)

Incubation (if starter culture is added)

Ripening and drying

Process flow for dry sausage manufacture

Ingredient selection:

The main ingredients used in fermented sausages are; meat, salt, nitrite or nitrate salts, sugar, acidulants, starter cultures and spices.

Meat:

Only the highest quality of meat should be used in fermented sausages. When selecting meat, three criteria are important:

Wholesomeness- free of pathogens, parasites, chemical residues and physical hazards.
Functional characteristics- composition, pH and binding properties.
Color- meat color is affected by species, freshness and pH.
For optimal meat quality:

Chill fresh meat rapidly and keep cold
Use meat soon after slaughter (within three days)
If not use immediately, freeze meat as soon as possible.

Salt:

Most fermented products contain between 2.5-3% salt. The main characteristics salt brings to the fermented products are flavor and binding. The salt used in meat products should be free of impurity; which if present in meat could lead to fat oxidation.

Nitrate/Nitrite:

To inhibit the growth of Clostridium Botulinum spores and development of their toxins in shelf stable cured products. Nitrate, rather that nitrite, is added in the process of slow fermented sausages. Nitrate itself does not have a significant impact on bacterial growth, therefore has to be transformed to nitrite. Bacteria called Micrococci that are usually contained in the starter cultures make this transformation possible.

Sugars:

Sugars are added to provide nutrition for fermenting bacteria. The most common sugaradded is dextrose, but other sugars such as sucrose, corn syrups, glucose and brown sugar. The more sugar that is used, the more lactic acid results, so the lower the pH will be.

Acidulants& Spices:

Acidulants are acid substances that may be used to reduce the pH of the emulsion. And spices are aromatic substances that are usually added to improve the flavor of the product.

Should People “At Risk” Eat Dry Sausages?

Because dry sausages are not cooked, people “at risk” (the elderly, very young children, pregnant women and those with weakened immune systems) might want to avoid eating them. The bacterium E. coli O157:H7 can survive the process of dry fermenting, and recently some children became ill after eating dry cured salami containing the bacteria.

SAUSAGE STORAGE CHART

If the sausage has a “use-by” date, follow that date. It is the last date recommended for the use of the product while at peak quality. The date has been determined by the manufacturer of the product.
If the sausage has a “sell-by” date, or no date, store it for the times recommended below.
Sausage Storage Chart
Type of Sausage
Refrigerator – Unopened
Refrigerator – After Opening
Fresh Sausage, uncooked
1 to 2 days
(included in unopened storage)
Fresh Sausage, after cooking by consumer
(not applicable)
3 to 4 days
Hard/Dry Sausage
indefinitely in refrigerator; 6 weeks in pantry
3 weeks in refrigerator, or until it turns rancid
Hot Dogs and other Cooked Sausage
2 weeks
7 days
Summer Sausage (Semi-dry)
3 months
3 weeks
Freeze if you can’t use within times recommended above for refrigerator storage. Once frozen it doesn’t matter if the date expires because foods kept frozen continuously are safe indefinitely. However, for best quality use within 1-2 months.

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ÖZET

Ulusoy B. H. (2007). Kefir Kültürü ile Fermente Sucuk Üretimi. İstanbul Üniversitesi Sağlık Bilimleri Enstitüsü, Besin Hijyeni ve Teknolojisi ABD. Doktora Tezi. İstanbul. Bu çalışmada, fermente sucuk üretiminde, kefir kültürünün ve çeşitli oranlarda klasik sucuk kültürüyle kombinasyonun starter kültür olarak kullanılmasının mikrobiyolojik ve kalite yönünden uygunluğu araştırılmıştır. Bu amaçla, sucuk hamuru hazırlandıktanve 10’ar kg’lik gruplara ayrıldıktan sonra A (kültürsüz, kontrol), B (109 kob/ml’lik kefir kültürü stok solusyonundan 100 ml), C (109 kob/ml’lik sucuk kültürü stok solusyonundan 100 ml), D (Kefir kültürü stok solusyonundan 10 ml + sucuk kültürü stok solusyonundan 90 ml) ve E grubu (Kefir kültürü stok solusyonundan 90 ml + sucuk kültürü stok solusyonundan 10 ml) olmak üzere 5 gruba ayrılmıştır. Deneysel sucuk örneklerine 6 günlük olgunlaştırma ve 30 günlük +4˚ C’de muhafaza süresi boyunca mikrobiyolojik (toplam mezofil aerob bakteri, toplam aerob psikrofil bakteri, koliform ve Escherichia coli, sülfit indirgeyen anaerob bakteri, laktik asit bakterileri, Enterokoklar, stafilokok-mikrokok grubu bakteriler, Staphylococcus aureus, küf-maya sayımı), fiziko-kimyasal (pH, su aktivitesi, rutubet) ve duyusal analizler yapılmıştır. Elde edilen sonuçlara göre, fiziko-kimyasal analizlerden pH sonuçları, tüm grupların hamurlarında 5,80 civarında tespit edilirken, olgunlaşma dönemi boyunca pH düşmüş ve muhafaza sırasında gruplara göre değişen günlerde yükselmeye başlamıştır. Muhafazanın son gününde A grubu 5,55 ve diğer gruplar ise 5,18-5,26 arasında pH değerine sahip olmuştur. Deneysel sucuk gruplarının hamurlarında 0,97 civarında olan su aktivitesi değeri bütün gruplarda olgunlaştırma ve muhafaza dönemi boyunca düşüş göstermiş, 30. günün sonunda A grubunda 0,86 ve diğer gruplarda 0,85 civarında su aktivitesi değeri tespit edilmiştir. 30 günlük muhafaza sonunda A grubu % 37,0 rutubet oranına sahip olurken, B, C, D ve E gruplarında bu oran % 36 civarında tespit edilmiştir. Mikrobiyolojik analiz sonuçlarına göre, Staphylococcus aureus, Escherichia coli, sülfit indirgeyen anaerob bakteri ve koliform bakteriler gibi ürün hijyeni ve halk sağlığı açısından risk taşıyan bakterilerin kefirle üretilen sucuk gruplarında diğer gruplara kıyasla muhafazanın daha erken dönemlerinde inhibe olduğu tespit edilmiştir. Muhafazanın son gününde A, B, C, D ve E gruplarında küf-maya sayıları 5,30 ile 7,84 log10 kob/g arasında değişmiştir. Kefir kültürü ile üretilen fermente sucuklar, duyusal özellikler bakımından da panelistlerden beğeni toplamıştır. Sonuç olarak fermente sucuklara kefir kültürü ilavesi mikrobiyolojik kaliteyi olumlu yönde etkilerken tad ve aroma bakımından da kabul edilebilir düzeyde olduğu tespit edilmiştir.

Anahtar kelimeler: Kefir kültürü, fermente sucuk, starter kültür, fermentasyon

Bu çalışma, İstanbul Üniversitesi Araştırma Projeleri Yürütücü Sekreterliği (proje no:T-515 /21102004) ve TÜBİTAK (proje no: 105 O 691) tarafından desteklenmiştir.

ABSTRACT

Ulusoy B. H. (2007). Production of Fermented Sausage with Kefir Starter Culture. İstanbul University, Institute of Health Science, Department of Food Hygiene and Technology. Doctorate thesis . İstanbul. In this study, inoculation of kefir culture and its combinations were studied. After preparation of fermented sausage mixture, it was divided into 5 parts 10 kg dough and each part was inoculated with different ratio of kefir and classical fermented sausage culture and named as group A (no starter culture, control), group B (100 ml from kefir 9 culture stock solution with 10 cfu/ml viable cell), group C (100 ml from sausage 9 culture stock solution with 10 cfu/ml viable cell) group D (10 ml from kefir culture 9 stock solution with 10 cfu/ml viable cell+90 ml from sausage culture stock solution with 109 cfu/ml viable cell) and group E (90 ml from kefir culture stock solution with 9 9 10 cfu/ml viable cell+100 ml from sausage culture stock solution with 10 cfu/ml viable cell). Microbiological (total mesophyl aerob bacteria, total psycrophyl aerob bacteria, coliform ve Escherichia coli, sulfite reductating anaerob bacteria, lactic acid bacteria, enterococcus, micrococcus/staphylococcus, Staphylococcus aureus, yeast and mould), physico-chemical (pH, water activity, moisture) and sensorial analysis were performed during 6 days of ripening and 30 days of storage at +4˚ C. According to the results that obtained; pH of all groups were about 5,80 and decreased during ripening in all groups and started to increase at different days of storage. At the end of storage, ph values were 5,55 in group A and between 5,18-5,26 in the other groups. Water activity was about 0,97 in the dough of all groups and decreased to 0,85-0,86 at the end of storage. Moisture percentage of the experimental sausage dough was about 36-37% at the end of the storage period. According to the results of microbiological analysis it was seen that, the bacteria that concern public health such as Escherichia coli, coliform, sulfite reductating anaerob bacteria, Staphylococcus aureus were inhibited in the earlier stages of ripening or storage in the groups that inoculated kefir culture than the ones with no kefir. Yeast an mould counts of A, B, C, D ve E groups were changed amoung 5,30 and 7,84 log10 cfu/g. On the other hand, the groups with kefir culture were given higher scores than the other groups by panelists in the sensorial evaluation.

Key Words: Kefir cultur, fermented sausage, starter culture, fermentation

The present work was supported by the Research Fund of Istanbul University (Project No. T-515 /21102004) and TÜBİTAK (Project No. 105 O 691)

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Fermentation of yoghurt is the most important part of the production.For fermentation process ,streptecoccus thermophilus and lactobacillus bulgaricus are added at 1:1 ratio as starter culture.There are also other bacterias in the product such as mold and yeast ,lactic acid bacteria etc. Detection of these microorganisms has an important role for safety of products. In this experiment we have used two kinds of yoghurt sample prepared in aceptic conditions and in open environment.We have examined the differences in the number of microorganisms in these samples.We have used different agars fort hat purpose.That is because,total lactic acid bacteria can be determined with MRS agar ,s.thermophilus and lactobacillus bulgaricus can be differentiated by using lee’s agar. Because , s.thermophilus ferment sucrose and produce yellow color but l.bulgaricus can’t so that we can differentiate them from each other by using lee’s agar.In M-17 agar, reproduction of s.thermophilus bacterias is observed.In PCA agar, at 30 °C microorganisms other than lactic acid bacterias can be detected.Also during sample preparation, we diluted our sample with a different way because that our sample was solid so we took 25 gr and dissolved it in 225 ml of sterile water to obtain a well mix.In the results,the number of microorganisms in open yoghurt are greater than the number in pasteurized yoghurt. That is because,in pasteurized yoghurt,the yoghurt product is pasteurized during the production so the number of microorganisms is reduced because of heat threatment and aceptic packaging.But in open yoghurt,it is produced in open environment so the product is exposed to air and other factors such as human interferences and non aceptic packaging.However,we have also observed that the results are a bit strange and unacceptable.Because when yoghurt samples are diluted and inoculated ,the obtained number of microorganisms are greater in so diluted samples such as 10-5 such as 10-2 because of wrong calculations or careless experiment work etc. or 10-6 than less diluted samples or 10-3 .This is not an expected case.This mistakes may be

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The main lactic acid formers are homofermentative lactic acid bacteria such as Streptecoccus thermophilus, Lactococcus lactis, Lactococcus lactis subspp cremoris. Lactic acid vary in rate of acid production. The rate is influenced by temperature, pH, antibiotics, bacteriophage, stimulants, inhibitory compound, milk composition, available nutrients, condition of the culture, strain compatibility and strain dominance. The term starter culture refers to a culture of lactic acid bacteria in food which is used to induce a lactic acid fermentationto produce fermented products.the particular lactic acid bacteria required in any given starter culture depend on the purpose of use. In cheese making an active production of lactic acid is an essential requrement and cultures may consist of Lactococcus lactis, Lactobacillus helveticus, Lactobacillus bulgaricus, of combination of these with or without aroma forming bacteri. Microbial spoilage in cheese is generally limited because of the combined effect of acid, salt and low moisture. Fresh cheese may be spoiled by gram (-) psychrotrophic bacteria (Flavobacterium, Psedomonas or Alcaligenes), coliforms, yeast and molds that enter as post- pasteurization contaminants. The most common pathogens in cheese are Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella, Brucella.

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