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Cheese is a type of fermented solid food made from the milk of animals. Generally, there are hundreds types of cheese in this world. For cheddar cheese, it is made manually till the day Joseph Harding, who is a Somerset dairyman presented the way of mechanization and standardization in 1856. The main purpose of mass producing cheese is cheese is to meet the requirement of the people as cheese is becoming one of the most used ingredients for food all around the world.
As it is mentioned that there are few hundreds of cheese in this world, the process of making cheeses will also be different considering the types of cheese product desired. In this report, we are going to include the general processes of cheese manufacturing and processing methods. Besides, we are going to give the overview of the cheese manufacturing industry too, like industry's importance, supply and demand, impact of industry to environment, processes involved and not to forget the role and skills required by chemical engineer in the industry.
2.0 Importance of cheese making industries
Cheese making industry as a sub industry in dairy products industry in Malaysia, produce cheese that rich in nutrient for our society. As cheese is made from milk curd, cheese naturally contains many nutrients including phosphorous, calcium, protein, fat soluble vitamins and B vitamins.
As cheese is also one of the main ingredients in food, mainly western food, it's demand from the whole world is quite high and increasing from time to time. Due to the high demand, this industry become undeniably important to supply cheeses to the market.
On the other hand, the industry also provides another choice of food aside from the traditional food of our country. Besides, cheese manufacturing industry had generated jobs opportunity for the peoples in this country over the years. Availability of job opportunity is important in the development of country by stabilizing the economy. When this issue is look from a larger and wider range, the large amount of cheeses produced might as well being export to other countries and this might earn the production country a great profit thus improving economy of the country itself. Besides that, the industry also may bring in the technique of manufacture cheese from the western countries. This is also helpful in the modernization of our country's industry and as a catalyst to achieve our vision which is become a developed country in year 2020.
3.0 Supply and Demand of Cheese
Cheese is a dairy product made from milk which undergoes several process before become cheeses. Besides that, cheese is also widely used in many countries especially in developed countries like, United States of America, European countries and also in Asian countries. It provides healthy nutritional value and rich in protein. The annual market supply in 2009 is approximately 30,000 tons and the growth rate in recent years is 20%. There major cheese consumer group are overseas returnees, foreigners in china and young blood as they accept the western cultures.
Other than that, the global reports have also predicted that the cheese market will develop more than 20% between 2008 and 2015. Besides that, a report from USDA has stated that an average cheese consumption per person have tripled from 11 pounds to 31 pounds per person between 1970 to 2003, where , majority of Americans favorite cheese is mozzarella, cheddar and cream cheese. United States of America is also well known as one of the largest cheese producers in the world as most of the people in United States used cheese in their daily food intake.
Moreover, in Britain, the cheese sales rose 16% between 2004 and 2006 to reach ¿¡220 million. Besides that, about 52 % of all cheese sales are cheddar from the United Kingdom and abroad. The cheddar sales have reach ¿¡985 million between 2004 and 2006 with a growth rate of 7%. The British cheese market was worth of ¿¡1.9 billion in the year 2006. The cheese consumption among school children is always steady as the British cheese board launches the 'choose cheese' campaign.
Other than that, the cheese market in India has also shown a balance growth rate about 15% to 20% per year. Based on the report generated by Agri-Commodity Federation, it has stated that the national cheese consumption in India is 70,000 tons per year, where 60% of the cheese sales come from metropolitan cities and smaller cities prefer cottage cheese.
Whereby, china's cheese market is still in infancy rate. Where, the normal cheese consumption per capita in developed cities is only 20 grams. In addition, cheese products are not found in most of medium and small cities. Due to china's rapid economic development and increasing frequent international exchanges, china is expected to have a huge cheese demand which can generate the extensive market.
4.0 Prospect of the Industry
Cheese manufacturing industry is expected to experience growth in the future years. There are factors which contribute to the growth of this industry. First of all the major factor for the growth is the multicultural background of our society had facilitated the acceptance of cheese in our country. Unlike western countries, where cheese is one of the major source of nutrient, Asian especially East Asian is not a big fans for cheese. However Malaysia as a melting pot of cultures, easily accepted the food which brought from the western. The impact of cheese on local food is clearly shown when you see people ordering roti canai cheese, cheese nan in mamak stall. It indicates that cheese had somehow adapted to the recipe of our foods and changing dietary preference of our peoples.
The other contributing factors are the increases of buying power leads to the diet modernisation of our society. Western restaurant, which was once a luxury for peoples, is now can found in every corner in our country. Rapid growth of quick-service restaurant, for example Pizza Huts, Secret Recipe, Wendy's indirectly promotes the tastiness of cheese. Moreover, degree of health awareness of consumer is increasing as well. Cheese which is made from milk is rich in nutrient elements such as calcium, phosphorus, zinc, vitamins B. Besides, cheese also helps in bone formation and tooth enamel protection. Furthermore the retailers' advertisement and marketing strategy had helped to boost the popularity of cheeses. Hence the demand for cheese is expected to increase as well.
The negative part is Malaysia relying heavily to imported dairy products. Milk which is the most important ingredient to make a cheese is imported in powder form from Australia and New Zealand too. This subsequently increases the cost of cheese making. In Ninth Malaysia Plan (2006-2010), Malaysia government had invested RM4.4 billion for modernising agriculture farming. With the new technique, agriculture sector is expected to provide cheap and sustainable source of ingredient for cheese manufacturing industry. Sustainable ingredient helps the research and development of new cheese type too since choice of cheeses in this country is still limited. Furthermore food creativity is a strength of Malaysian.
Overall cheese consumption continues to increase due to its versatility and adaptability to recipes, more available varieties. The consumer shift from at-home food preparation to purchases of partially or fully prepared foods has also benefited cheese sales.
5.0 Impact to the environment
Production cheese which is mainly made from cow's milk, has a large impact to the environment. The production of 1.5 ounce serving of cheese is expected to produce about 16 ounces of carbon dioxide. As carbon dioxide is one of the main causes of greenhouse effect, this is the major impact to the environment in producing cheese. When the cheese undergoes lesser processing steps, it brings lesser harm to the environment. This especially happens during the process of ripening, mainly because of the electricity needed to provide a low and steady temperature as they matured. Therefore, soft cheeses are most probably more environmental friendly compared to the hard ones since the hard cheeses require more milk, longer ripening period and cooking.
In the production of cheese, the liquid waste is mostly from the making of whey, wash water and also curd particles. For cottage cheese curd, it is more fragile compared to the rennet curd. Hence, the whey and the wash water from the cottage cheese are most probably to have more fine curd particles than the others. Mechanical washing will increase the fine particles in the wash water. The waste water from the manufacturing of the cheese contains a significant amount of cleaning substance and sanitizers. Besides, the waste water also have a high BOD(biochemical oxygen demand) and COD(chemical oxygen demand). The next thing is the waste water from the production of cheese are normally acidic because of the production of lactic acid in the waste water.
However, the whey produced is now being used as one type of energy source. Using anaerobic digester, the lactose in the whey is converted into methane and carbon dioxide. Each cubic meter of whey will then produce approximately 20 cubic meters of biogas. The biogas is then used to generate electricity and heat generated will be used to heat up water in production processes.
There is very less solid waste produced in the production of the cheese. The solid wastes produced in this industry are mainly the sludge after the waste water purification.
6.0 Processes Involved :
6.1 Standardization and Pasteurization of milk( by Ooi Kai Loon0907020 )
Cheese comes in many varieties. The variety determines the ingredients, processing, and characteristics of the cheese. However the most important ingredient in cheese making is milk. Before the actual cheese making starts, the milk needs to undergo pre-treatment which is Pasteurization process. The goal of this process is to kill microorganism especially bacteria that causes disease.
Although cheeses that did not undergo this process are claimed to have a better flavour and aroma, most producer are not willing to take the risk since it may cause food poisoning to consumer.
In general, fresh milk is flow into continuous-flow pasteurizer. The pasteurizer is divided into two parts, cooling section and heating section. In heating section, the milk is forced through pipes heated on the outside by hot water to a high temperature to kill the microorganisms. There are two ways to heat up the milk, which are High Temperature Short Time (HTST) and Ultra High temperature (UHT). For HTST method, milk is heated to about 72°C for 30 seconds while UHT method heated the milk to 140°C for 3 seconds. However high temperature short time method is more commonly used because the producers claim that ultra high heat destroys the nutrients in the milk. After that the milk is flowed to the cooling section for quick cooling to 32°C. After that the milk flows out and go into standardization process.
Standardization is the process of standardizing the fat content of the milk desired value depending on the type of cheese being made. Fat content of the milk is calculated based on the relative amount of protein fat. To do that, pasteurized milk is directed into a separator. When the separator spins, because of different density of fat and milk, the two substances is separated whereby the fat form a layer on top of the milk. The fat and milk is then flow out of different pipe(?), milks goes to a container while cream is then collected at the cream standardization part. The cream standardisation section act as regulator to control the flow of cream which will then remix into the milk again to get the desired fat content. After that, the standardisation process is complete and it will enter the filtration process.
6.2 Filtration and Coagulation (Kong Suyan 0903195)
Ultrafiltration (UF) of membrane concentrated milk is used to improve solids level of the cheese milk which means by pre-concentration of cheese milk. The fat and protein of the concentrated milk is increased to 3.5 times by using the method UF. Besides that, a portion of the water and lactose was removed, which possesses the ideal composition of the manufacture of the fresh cheese. UF milk makes the opportunity to boost total solids by replacing 10-15% of cheese milk volume. So, UF help factory to reduce the production costs which UF can increase the cheese production by as much as 18%.
In addition, by using the UF milk can reduce the cheese plant's wastewater processing costs. This is due to UF permeate contains solids, processors could choose to install a reverse osmosis (RO) unit to concentrate the permeate solids. The permeate stream from RO can be polished by another RO units and used at the plant for virtually anything except final rinse water and drinking. Furthermore, by using this polished water can also reduce the plant's water costs.
However, the concentration of cheese production may not be limited in the cheese making by the membrane process. Microfiltration (MF) should yield casein enriched cheese milk that can be ideal for semi-hard cheeses.
Coagulation is mean by the collecting into a mass of minute particles of a solid dispersed throughout a solution, and it's usually followed by the precipitation or separation of the solid mass from the solution. The casein in milk is coagulated by the addition of acetic acid. The albumin in egg white is coagulated by heating is another example of coagulation. Besides, coagulation normally involves a chemical reaction.
Coagulation by destabilizing the casein micelles in cheese manufacture process is the formation of a gel. This process cause them to form and aggregate a network which partially immobilizes the water and traps the fat globules in the new type of matrix.
When rennin which is an enzyme is stirred into the milk, the curds are formed. Rennin encourages casein to solidify and clumps together. Rennet contains the enzyme chymosin which converts k-casein to the main component of the cheese curd and glycomacropeptide, which lost in the cheese whey. Rennin and chymosin is found in rennet, and it aids only forb coagulation if the milk slightly acidic, when it becomes sour. Cheese makers speed up the process by adding specialized bacteria and warming the milk that convert the sugars to lactic acid which found in the milk, which creating the acidic environment required far casein coagulation, rather than waiting for milk to sour,. When the casein clumps together, it traps some of the milky liquid and fat globules inside the clump, nutritious curds, forming moist.
The first fundamental of cheese making is coagulation of milk. However, there is much more to it than that. As the curds form, cheese makers have to remove all traces of sugary residue that is left behind. This whey must not be wasted. It is the part of milk that goes off easily. If the curd is removed, it is then collected together and salted to preserve the cheese.
6.3 Cutting, stirring and cooking (Thineeshan A/L Ramasamy 0905588)
The process that takes place after coagulation(curdling) is the cutting process. Before this process takes place, a simple test is normally carried out to obtain the whey eliminating quality of the cheese. In most cases, a long, blunt knife is put into the coagulated milk and is then slowly removed upwards until proper breakings are formed. When a glass-like splitting flaw is observed, the cheese is considered ready to proceed to its next stage otherwise will be coagulated again to ensure the smooth cutting of cheese into smaller parts.
Stirring is another important process in cheese production. The curd grains obtained from the cutting process are sensitive to mechanical stirring, thus a gentle yet fast enough stirring is required to prevent the grains from sinking to the bottom of the vat. Grains which sink causes formation of lumps at the bottom of the vat which affects the stirring tendency by causing higher power usage for stirring purposes. These lumps also contributes by influencing the texture of the cheese besides causing the loss of casein in whey.
The next process is where the heating and cooking takes place. The size and acidification of curd is determined by the heat treatment supplied to the stirred mixture of curd grains. This heat produced limits the growth of acid-producing bacteria which is then used in the production of lactic acid. Lactic acid is responsible in reducing the sensitivity of the curd grains. There are primarily three ways of heating which are :
* By steam in the vat/tank jacket only
* By steam in the jacket in combination with addition of hot water to the curd/whey mixture
* By hot water addition to the curd/whey mixture only
Heating period and temperature are down to the choices of heating and the type of cheese itself. The term cooking is used when the heating temperatures are above 40°C. Heating is basically done to kill off bacteria's and in cheese production, mesophilic lactic acid bacteria's are aimed to be killed off. Between 37 - 38°C, this bacteria's mobility is handicapped. This opportunity is used to check the acidity of the mixture and heating is resumed afterwards. This bacteria will be killed off when temperature is maintained at 52°C for around 10 to 20 minutes.
6.4 Cheese milling & Cheese salting (Sivamanickam A/L Omandran 1100426)
Cheese milling is a process where the cheese curd is run all the way through a mill and chopped into smaller size which will help the salt to penetrate easily inside the curd . Besides that, smaller sizes of cheese curd are also easier to keep in the hoops and pressed into the shape desired.
For the cheese making process to be successful, salt plays a major role. The salting process is a process where it functions to speed up the drying process, helps the rind to form, heightens the cheese's flavor, regulates certain bacteriological processes and slows down the production of micro-organisms. The common type of salt we used in this process is sodium chloride (NaCl). There are several type of salting method, they are:
Hard pressed cheese
Soft cheese salting
Blue-veined cheese salting
However, the most common method used widely worldwide is brine-salted cheese method where they immersed the cheese in a brine bath with specified salt content as different cheese have different salt content. The brine-salted method is more widely used because the cheese salt absorption is efficient and gives desired taste, meanwhile maintaining the cheese structure.
To ensure the brine-salted process to be efficient, time saving and economical, several factors have to be considered. One of the factors are the cheese moisture content where cheese with higher moisturize content will absorb salt concentration faster than those cheese with low moisturize content. Other than that, the cheese acidity also must be considered as different type of cheese has different type of acidity where the cheese with higher acidic condition will absorb the salt faster. Besides that, another factor we must study on is the shape and the weight of the cheese. This is because a flat and thinner cheese can absorb salt faster than a thick cheese, moreover the edged cheese brined faster then the round cheese as the brined cheese expose more surface area. In addition, to ensure the brine-salted process to be more efficient, the temperature and the salt brine concentration have to be considered. This is because, higher temperature can increase the penetration rate of the salt and can minimize the time taken for the salt to penetrate inside cheese. Besides that, the concentrated salt brine can increase the rate of salt absorption by follows the concentration gradient.
The brine-salted processes normally take place in circulating brine salt basins or in basins of still standing brine. If the brine-salted process take place in the basin of still standing brine, than the brine have to be stirred frequently because there will be some un-dissolved salt accumulation at the bottom of the basin. Whereby, if the brine-salted process takes place in a circulating brine salt basin, we no need to worry of accumulation of un-dissolved salt at the bottom of the basin as the brine is circulating and the strength of the brine can always kept constant.
The optimum strength for most cheeses is 20 -22 Beau me degree, where 21% - 23% salt dissolved. Besides that, a normal brine salt can be prepared by using clean potable water. The brine-salted process must be conducted at the optimum temperature within the range of 25°C to 30C, as the salt dissolving rate is higher in this range of temperature and in meanwhile, we can avoid the accumulation of nitrate which can make the brine unsuitable. Once the salt brine is in optimum concentration and temperature, the salt-brine process will take place efficiently.
The concentration of the salt brine must always be checked with density meter as the salt brine will fluctuate to the same Ph level with the cheese after some time. Therefore, the ph value of the brine is adjusted by poring some HCl into the brine and another 0.5 % CaCl2 (calcium chloride) is added, to avoid cracks and brown dis-colouring in the rind. No matter what we do, the small amount of sludge formation cannot be avoided, so we should remove the sludge by fishing it up everyday. With a regular daily service, maintenance, kept clean and maintain with proper temperature and strength, the brine have unlimited lifetime.
6.5 Pressing and Ripening (Lee Chee Yung 0903048)
The curd need to undergo the process of pressing. The four main objectives of pressing the cheese is to help in the final whey elimination, to shape the cheese and finally to provide the cheese to have a longer ripening period. When the cheese is pressed in the mold, the additional whey that still contained in the cheese will be removed. The mold which is holding the cheese is designed in a way that allowing the water to escape from it. In the case of pressing, the pressure is applied gradually to the cheese. The reason behind this was high pressure applied to the cheese will cause the moisture to be locked in the body of the cheese. After the cheese is pressed, the cheese will undergo ripening process.
Ripening process is vital, since it determines the flavors and also the texture of the cheese. The cheese will undergo a series of processes including microbiological, biochemical and also physical process. The kind of bacteria used, temperature and relative humidity of the environment and also the time of ripening period will determine the characteristic of the cheese produce. In some cases, certain bacteria is added in this process. For examples, the Penicillium roqueforti is added to ripe cheese named Roquefort. This mould creates a special bluish-green veins o the cheese and produces sharp flavours and creamy texture.
A ripening room is generally a room that is under control to provide desired environment needed to produce certain type of cheese. The ripening room is normally kept cool, this is to encourage the activity of the ripening bacteria and also prevent the harmful bacteria from spoiling the cheese. For Cheddar family cheese, 4-8°C and relative humidity lesser than 80% is required and the time for ripening may vary from few months to 10 months depends on the consumers. For some of the smear-treated cheese like Tilsiter, it is being stored in a fermenting room which has the temperature of about 16°C and relative humidity for about 90% for 2 weeks. Once the smear layer is sufficiently developed, it is transferred to ripening room which has a temperature of 10-12°C and relative humidity of 90% for two to three weeks. Besides all of this condition, the cheese somehow also needs to be turned in a certain period of time. This is to ensure there is a standard moisture distribution in the cheese. If the cheese is not turned, the moisture will accumulate at the bottom part of the cheese. It not only dissolves the cheese rind, it also causes the cheese to become sour at the moist side, which is the bottom part. This is because the whey contains a large amount of acid.
Nowadays, radio frequency identification(RFID) is also implemented to the ripening process. RFID basically simplifies the process of ripening. The RFID transponder will store particular information for that particular cart of cheese including the starting time of the process, the destination point where it should be sent to. RFID scanners are also installed at the entrances of every ripening room to monitor the cheese's storage period. All of this information is being monitored, recorded and documented. The RFID system makes the process to be more precise because the location of each rack at any time and how long it needs to stay in each room is known.
The ripening process of the cheese is halted when it is matured enough to be sold to the market. The ripening process is stopped by immersing the cheese in the paraffin oil, thus preventing the cheese being contact with the outside air. Besides, the paraffin oil also protects the cheese against dehydration and mould.
7.0 Role of A Chemical Engineer in Cheese Production Industry
The role of a chemical engineer plays today's world is very important. There are a lot of responsibilities in which chemical engineer should undertake on a daily basis and various specific duties that must be carried out as well. Besides, it is important to know why the role of chemical engineer is very important and whether one is suited for a job.
What is a chemical engineer? This is the typical question asked by everyone. Chemical engineer is an individual that who works with responsible for manufacturing chemicals and developing the processed. Besides, they also will develop the chemical plant design as well. Some of the products which involving the chemical engineer with developing, such as rubber, plastic and food. Furthermore, chemical engineers face many of the challenges which also faced by other professionals. They meet these challenges by applying their technical knowledge, communication and teamwork skills, the most up-to-date practices available and hard work.
For our group, we had chosen the food processing as our reference industry. There are many type of final products that can categorized in food processing such as coca-cola, instant noodle and cereal. Therefore, we all had decided that cheese production as our final product. As a chemical engineer, what are the roles that we should practice in manufacture cheese industry?
As we all know, cheese is made by adding coagulating milk, stirring and heating the curd, draining off the whey, collecting and pressing the curd, and sometimes ripening. As a chemical engineer, we should come out a chemical plant design in order to fulfill the process above in the industry. Before the developing the best chemical plant design, we need to do a lot of research from the beginning to analyze the best way to produce the cheese products. While doing the research, we have to design the programs, the machinery and the process required to allows the products to be manufactured. Besides, we also need to perform a multitude tests along the way to make sure everything is going on with the plan. Lastly, one who is a chemical engineer must consult with numerous individuals to make sure their job is done by their best ability and the best desired outcomes are reached.
Moreover, chemical engineering also develop curriculum and trained operators on shred lines to implement more effective methods for the production of cheese. As a chemical engineer, we must work closely with Research and Development department (R&D). The Engineering and Maintenance staff to assist with fault finding, equipment design installation, Sanitation and Food Safety Permit inspection of the cheese production and project reviews. We are require to provide technical assistance to give quality assurance personnel and sanitation supervisors to solve microbiological issues and cleaning, assist in the continuous improvement of sanitation crew effectiveness and performance. Another responsibility is to develop and maintain contracts within the cheese production is to maintain the most current and the latest information and industry direction that affect the operations of the cheese production company.
8.0 The skills/knowledge required by the engineer in food processing industry
All engineers make use of math, physics and economics. What separates a chemical engineer from other engineers is the additional application of chemistry in their field. Chemical engineers invent and design new processes or modify existing ones to generate the best yield at the lowest cost. They convert raw unprocessed items into useful products for people.
The role of a chemical engineer in food processing industry is quite evident, to deal with chemicals related to food. A chemical engineer in this area must master multiple aspects such as process design, hazard and risk analysis and also food rheology. In the cheese production industry, the chemical engineer involved must be able to design a process to manufacture cheese. Even though this could be done by most engineers, the skills needed afterwards are vastly related to chemicals thus proving the importance of a chemical engineer. Chemical engineers must not only be able to design the processes but also to predict the possible hazards and risks involved and ways to overcome it. For example, pasteurization is a normal procedure before making cheese. However, certain type of cheese may lose its flavor and aroma if heated over a specified temperature. A chemical engineer must be able to analyze and solve this problem. Another important skill needed is the study of food rheology. This study regards on the properties of food and helps determine its life span and texture. Besides, another important skill required by a chemical engineer in food processing industry is the ability to carry out experiments using different ingredients and additives to improvise tastes and textures.
Based on the discussions mentioned, few statements can be concluded. Importance of the cheese is mostly in the aspect of health, improving ones country economy and as in food ingredients. The next thing is the demand of cheese is also increasing from the whole world. For the prospect of this cheese making industry, it is expected that this industry will grow due to the increase in buying power and also the cheeses' adaptability to recipes. In general, cheese production do not brings much harm to the environment as less waste is produced throughout the whole process. Carbon dioxide formed from the breeding of cows till the production of cheese is the main concern. Whey formed can also be used to generate energy such as electricity and heat. The processes taken to make cheese can be broken down to five main parts, pasteurization and standardization, filtration and coagulation, cutting, stirring and cooking, miling and salting, pressing and ripening. Chemical engineers in this industry need to do research, design processes and programs, monitoring and maintenance, provide useful comments and also works closely with R&D departments. Chemical engineers in this industry need to have knowledge in food rheology and ability to carry out experiments using different ingredients to provide good taste.