Cheese facts
What is the ripening process also known as
Aging and curing
The traits that inhibit pathogen growth
Dry, acidic - low pH - and have a high salt content
Where did Gruyere get its name
it was named after the town Gruyeres in western Switzerland
Does listeria get into the cheese
Listeria contamination can be a consequence of them properly pasteurized milk, improper cooling of the milk, or post pasteurization contamination in the cheese plant or in the homes of the consumers.
How are Rennett coagulated cheeses made
Once the gel reaches a required consistency, it is cut into small pieces referred to as curds, another step that facilitates the expulsion of moisture, referred to as Whey , from the curds. Curds are separated from the way via draining , a step in which the curds maybe knitted and pressed together to form cheese wheels or blocks of various sizes and shapes salt, either in crystals or in a brine solution is applied either to the curds or to the more fully formed whole cheeses
What are the basic principles of cheesemaking
(1) Removal of water from milk, (2) breakdown of milk proteins (caseins), and fat, (3) addition of salt, (4) an optional ripening period
The three K's must be followed to prevent cheesemaking contamination
(1)- keep the pathogens - undesirable microbes - out through sanitation. (2) - kill them - with heat or antimicrobial treatments (3) - keep them from growing - temperature, salt content
A significant step in transforming milk into cheese is converting liquid milk into a gel, consisting of a network of casein proteins whose formation depends on acidification of the milk and subsoquent coagulation of those proteins
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How many cheeses does the U.S. produce
1700
Who was Louis Pasteur
A French microbiologist and chemist, was central in demonstrating the existence of microbes and that microorganisms are responsible for many common phenomenon associated with food including the fermentations that produced beer wine and cheese. He also showed that these microscopic organisms could be in activated by heating liquids such as milk followed by rapid cooling, a process that later became known as pasteurization.
What is ripening
A maturation or aging step after initial cheesemaking that in parts distinguishing flavors, aromas, and textures to particular cheeses
What is fermentation
A microbial process that depends on metabolic enzymes to break down complex substances into similar ones that maybe safer to consume and typically can be stored for longer than could be original material. This process also may lead to acidification of a substance as occurs when lactic acid bacteria convert lactose sugar to lactic acid. Fermentation can also produce carbon dioxide and flavor compounds in cheeses or other materials
Casien
A milk protein that gels or solidifies during coagulation
What is draining
A process that removes and separates liquid whey from curds
What happens during the ripening process
A second wave of diverse bacteria and fungi, secondary microbiota, grow within the cheese and on its surface, sometimes forming a rind, the exterior outer layer of a ripened cheese
Depending on the cheese variety, three mechanisms to coagulate those proteins are drawn on to produce three very different families of cheese. What are the three mechanisms to coagulate proteins
Acid coagulated, acid heat coagulated, and rennet coagulated
What is acid coagulation
Acid coagulation occurs when bacteria in the warm milk (70-90F) convert lactose to lactic acid, which is allowed to accumulate to high concentrations. This accumulated lactic acid lowers the milk pH to the point where the repulsive forces originally present in the milk proteins are overcome, allowing these proteins to bind to one another forming a gel.
What three processes of coagulation exist
Acid coagulation, acid-heat coagulation, rennet coagulation
What is acid heat coagulation
Acid heat coagulation yields last lactic acid from lactose but heats the mixture to a much higher temperature, around 180°F, this combination also serves to overcome the repulsive forces originally present in the milk proteins, allowing the milk proteins to gel
What is Rennet
An enzyme preparation from animals, plants, or microbes that breakdown casein proteins in milk, leading them to coagulate
What are undesirable contaminating microbes
Any microbes that are not intentionally introduced during the cheesemaking process that lead to the development of off flavors such as bitterness and rancidity, poor texture, unappetizing appearance, or pose health risks from consuming the cheese product
What makes a cheese a "pasteurized process cheese"
Blend natural cheeses with emulsifying agents, preservatives, thickeners, flavorings, seasonings
How can contaminating microbes affect the cheese outcome
Both desirable and undesirable microbes are introduced to cheese during production. The desirable microbes include lactic acid bacteria in the starter culture and the secondary microbiota that dominate during the cheeses ripening and aging. Depending on the characteristics of the individual contaminants, they can accelerate typical flavor development, have no direct impact on flavor or can lead to development of off flavors
How do you increase the rate of fermentation
By warming the milk to the optimal growth temperature of microbes in the starter culture
What is microbial secession
Changes that occur within and among populations of micro organisms, including bacteria, yeast, and molds, during the ripening of chesses
Can acid coagulated cheeses and acid heat coagulated cheeses be aged
Characteristically they have very high moisture content, making them Bon Rabal to spoilage and difficult to write them for extended periods. Cheeses and these families are normally consumed fresh, with only a few examples of ripened acid and acid heat coagulated cheeses
Give examples of acid coagulated cheeses
Cottage cheese and cream cheese
Five categories of cheese based on texture
Creamy (mascarpone, contains, queso fresco and Blanco). Soft (brie, camembert, ricotta, cottage. Semisoft (mj, feta, blue, havarti, muenster, mozz, provolone) Hard (cheddar, Colby, Edam, Swiss, Gouda) Very hard (parmesan, Romano)
After coagulation, what is the next step of the cheesemaking process
Curd is cut to remove water (whey) from the cheese resulting in a semisolid to solid mass
(Texture) The texture of cheese depends on what?
Depends on the initial process during which the milk acidifies, the duration of ripening, and it's changing moisture content is the cheese . These factors control how much calcium will be retained in the cheese and the extent to which the milk proteins breakdown.
After starter cultures are added what process occurs
Fermentation, lactic acid bacteria breakdown (ferment) the primary milk sugar (lactose) into lactic acid
Jesus created by orderly secessions of microbial communities that produce compounds responsible for cheese flavor
For some cheese varieties like Romano, enzymes are added to create a specific flavor.
What does the acid produced during fermentation help to do
Form the curds also called a gel, it also contributes to syneresis of the curd, removal of water held within the milk protein
What cheeses have a higher rate /potential for contamination
Fresh, non-ripened cheeses such as queso fresco and washed rind cheeses have higher moisture content and a higher pH and then do other cheeses, these products are more prone to be contaminated with listeria and support its growth. Contaminated soft cheeses may therefore put the rest of people that are particularly vulnerable to listeria infections, including pregnant women, immunocompromised people, and the elderly.
Where did the name muenster come from
From the Latin word monastarium, and was first created in a monastery
Where did cheddar and Cheshire get their names
From the name of the village and County, respectively, in England where the cheeses were first produced
The amount of moisture remaining a cheese determine whether of the creamy, smooth, firm or hard
Harder keep the moisture in comparison the softer cheeses. Therefore, natural cheeses can be category according to their degree of hardness and softness
What happens when there are high levels of calcium phosphate in the cheese
High levels of calcium phosphate make the cheese rubbery and difficult to melt, whereas low calcium phosphate makes that cheese softer and easier to melt
Acid production influences how much calcium is bound to casein, via phosphate groups. The more acid that accumulates, the less, the less calcium phosphate is produced.
Less calcium phosphate makes that she softer and easier to melt
When did the production of cheese in America begin
In the 17th century when the English Puritans brought dairy cows and their cheesemaking craft with them to the new England colonies . Kindstead from the book American farmstead cheese, states that the American cheesemaking industry began in the Massachusetts colony by Puritans from East Anglia, England, who arrived in North America from 1629-1640.
What is microbial fermentation
Is in large part an enzyme dependent process during which protein catalysts made by the microbes breakdown complex substances in this case, the proteins and sugars within the milk, into simpler products that typically can be stored for longer periods than the original substance
The starter culture changes the cheese micro environment, affecting a variety of factors including?
It affects the pH, redox potential, levels of organic acids such as lactate and acetate, and other nutrients. As some of the lactic acid bacteria within the starter culture begin to die, the cells release enzymes that further breakdown of proteins, mainly casein, to small peptides and amino acids
What is chymosin
It is also referred to as renin, is the specific enzyme in rennet that is primarily responsible for degrading caseins and causing them to coagulate. Calf rennet's are widely thought to yield the highest quality cheeses
What is calcium phosphate (CP)
It is an inorganic ingredient of binds to casein, the major protein component of milk
Traditional cheesemakers relied on naturally occurring lactic acid bacteria in milk
It is now common to inoculate milk with industrial starter cultures (defined groups of bacteria) that are specifically chosen for use in cheesemaking
What is Listeria monocytogenes
It is one of the main undesirable microbial contaminants which the cheese industry must address, it can cause a serious illness known as listerosis and it has a mortality rate of 20 to 30%. L. Monocytogenes is widespread and can survive for extended periods in the environment a monks soils, vegetation, and water. It can also be found on the surface of equipment, walls and floors and farms and cheese production facilities. Listeria is often associated with vegetables, it can also hide in home refrigerators.
Where did Roquefort get its name
It was named after a small town of Roquefort-sur-Soulzon in France
What does lactic acid production do to the milk
Lactic acid production lowers the pH of milk and causes milk to separate into curds and whey. The milk protein casein is broken down
What we know about when cheese came to exist is that Neolithic humans in Anatolia - modern Turkey - begin the harvest and store milk as early as 7000 B.C.E. through analysis of fragments of pottery from that time that contain organic residues that serve as a telltale molecular fingerprint for the milk that was once stored in those pots
Many of these pottery fragments contain traces of milkfat or residues, indicating that a concentrated form of milk was placed in these pots 9000 years ago. Some of these early cheesemakers from Turkey migrated to Central Europe sometime during the next 1000 years, bringing with them their dairy animals and cheesemaking expertise. By 5500 BC, Neolithic farmers develop specialized ceramic sieves to separate curds from way and, here again, some of the sieves contain the telltale molecular fingerprints of milkfat. From around 3000 BC, when written language was protected by Sumerian's of Southern Mesopotamia, some recovered examples of those early texts contain references to cheese. Additionally evidence recovered from Egyptian tombs dating back to 3000 BC indicates that cheese was them being made in this region as well.
Starter cultures are classified as either?
Mesophilic, which means temperate - loving, or thermophilic, meaning heat - loving. In turn these organisms dictate the temperatures used in the cheesemaking process
Where do microbes come from and how are they introduced during the cheesemaking process
Microbes associated with cheese production can be introduced deliberately, added as a starter culture, or unintentionally, by people, animals, or insects and rodents and production equipment, all starter cultures using cheese manufacturer species that were originally isolated from cheese or milk. Microbes can attach to the milking animals teeth and enter into the milk upon collection. They're also environmental microbes from the Cheesehouse and aging facilities I can settle on the cheese as the product is being made and as it ages.
How long are mild cheddar, sharp cheddar, and extra sharp cheddar aged for
Mild cheddar - 2 to 3 months, sharp cheddar - 8 to 12 months, extra sharp cheddar - 18 months to five years
What is pasteurization
Mild heating process invented by Louis Pasteur that destroys pathogens and spoilage microorganisms in food such as milk
How do microbes affect the flavor, aroma, texture, and color of different kinds of cheese
Milk composition, steps and techniques, use during the process and the varieties of microbes being used dictate the flavor, aroma, texture and color of the final cheese product the microbes are particularly important their metabolic activity produce hundreds of compounds from the protein of back components and milk that affect the flavor aroma texture and color cheese
In cheesemaking what two things change during the process
Milk proteins change as well as sugars . In particular the milk sugar lactose is broken down into lactic acid by fermentation that depends on a group of bacteria referred to as lactic acid bacteria
What is nisin
Nisin is an antimicrobial peptide known as a bacteriocin and is produced by particular types of starter bacteria. The natural antimicrobial properties of nisin inhibit the growth of many potentially contaminating microorganisms, including important foodborne pathogen such as Listeria, Staphylococcus, E.coli (Escherichia), salmonella, campylobacter and clostridium
If the starter culture is not dying than the cheese is not growing. In fact these dead starter culture cells and derbies are an important food source for subsequent generations of microbes these are referred to as?
Nonstarter lactic acid bacteria (NSLAB)
Production of cheese -
Obtain the milk which contains raw milk microbes, make curds by adding starter cultures, drain curds and foreman to shapes , Cheese house microbes can occur , salting the wheels of cheese creates salt microbes, aging in a cave creates cave microbes
What is the last step of the cheesemaking process
Packaging and distribution, stringent quality control and monitor
(Flavor) Name different microbes
Penicillium Camemberti, Geotrichum candidum, kluyveromyces lactis, debaryomyces hansensi. These are characteristics of bloomy rind cheeses
The starter culture breaks the proteins, mainly casein, into what two components?
Peptides and amino acids
What does the process of natural ripening include
Periodically rubbing the cheeses with salt, wine, beer, fruit, juices or liquor to enhance flavor
After cutting the curd what is the next step of the cheesemaking process
Pressing or draining. Curds are drained, knitted, impressed to form a mass (wheels or blocks) there is also the addition of secondary microbiota, and or salt through washing, brining, or rubbing the cheese
What do Propionibacterium do
Propionibacterium convert some of the lactic acid produced by the starter culture into propionic acid, which contributes to the unique flavor of Swiss type cheeses, along with acetic acid, and CO2 gas. This gas collects at weak spots in the cheese matrix, building up pressure until holes form. A cheese that does not produce those holes is considered blind.
Cheesemakers can purchase industrial produced starter cultures or they can rely on the micros naturally present in raw milk to initiate fermentation
Reliance on industrial starter cultures result in more reproducible acid and flavor development
Cheese is produced by removing what and ending up with what
Removing water and yielding concentrated proteins, fats and other nutrients/vitamins
Give examples of acid heat coagulated cheeses
Ricotta and paneer
After the pressing or draining, what is the next step of the cheesemaking process
Ripening ware flavor aroma and texture develop. Ripening occurs in a controlled environment. (Specialized rooms, caves)
When and why is salt added
Salt, either in crystals or in a brine solution is applied either to the curds or to the more fully formed whole cheeses. the salt inhibits further growth of the starter culture, prevents growth of pathogens and spoilage microbes that are salt sensitive. It also selects for the growth of desirable microbes, and influences enzymes that break down protein and fat in ways that in particular flavors and textures
After the collection of milk, what is the next step of cheesemaking
Starter culture or natural lactic acid bacteria is added to milk.
Examples of thermophilic cultures- 132°F
Streptococcus thermophiles , Lactobacillus Helveticus, and Lactobacillus delbrueckii are associated with Swiss and Italian type cheeses
What are the key components of milk
Sugar lactose, fat and milk proteins called casien
What kinds of things can go wrong and cheese making
The activity of the starter culture is particularly important as the rate and level of acid production contributes to a very large extent in defining the final composition of cheese and the subsequent communities that help to create it. Inadequate process control encompassing all details of the manufacturing process is the primary problem that can lower the quality of cheese. Adequate testing must happen . Additionally, bacteriophages, viruses that infect only bacteria but not humans, can also contaminate the microorganisms involved and cheese making and inhibit initial fermentation. These viruses are hardy, and may be found naturally on our skin and within our intestines as well as the environment, water supply, many foods
What can the color of cheese be due to
The color of cheese may be due to added colorants , or have natural pigments such as carotene, that comes from the grasses that the milk producing animals eat. Additionally the microbes involved in the writing process can affect the color of a cheese, producing pigments as part of the microbial interactions with the ingredients and cheese. Furthermore, nontoxic bleaching/coloring additives such as titanium oxide, hydrogen peroxide, benzoyl peroxide, and annatto can be added to the milk to alter the color and appearance of some cheeses
What is microbial ecology
The competition and cooperation among microbes that play a significant role in the conversion of milk to cheese
What is the concept of terrior mean
The concept hypothesizes that it regions landscape, climate, soil, people and animals deliver a geographically distinct property
The identity of most cheap types are based on what
The microbial communities that make up the cheese. Bacterial species that withstand temperatures as high as 132°F during fermentation are referred to as thermophilic .
Why do some cheeses melt and other cheeses do not
The flexibility of a cheese when it is heated depends upon the amount of calcium phosphate remaining in the cheese matrix and the extent to which casein has been broken down. In these two processes the microbes in cheese are directly responsible.
What is microbial succession
The metabolic activities of the cheese microbiotic change conditions (like microbial nutrients and concentration of lactate) within the cheese matrix. These changes allow other micro organisms to thrive and eventually to dominate the cheese microbiotic. This process is referred to as microbial secession an example is the development of the characteristic appearance of Swiss cheese
Can pathogens grow in cheese and make me sick
The occurrence of pathogens in cheese that cause disease in humans is very rare, however some pathogens can survive and grow and cheese when particular production standards are not met. They can contaminate the milk, the processing environment, the people working in the cheese plant .
(Aroma) In general, the more extensively the casein and fat in milk that are broken down, the stronger the cheese
The olfactory bulb gives us our sense of smell
What is syneresis
The process that allows curds to contract and expel way, removing water and other dissolved ingredients from the gel to achieve the desired texture and moisture content of the cheese being made
Acidification
The production within or addition of an acid to the milk fermentation mixture lowering its pH. Most commonly cheese acidification is due to production of lactic acid from lactose via fermentation that depends on the starter culture containing lactic acid bacteria (LAB). Alternatively the pH is lowered by adding food items such as citric acid, lemon juice, or vinegar, which are known as acidulants.
(Texture) texture can also be affected by Crystal formation
The ratio of salt the moisture influences the final pH that can cause crystals to form on and within the cheese. Gritty crystals are considered a costly defect in cheeses like cheddar. However hard cheeses like Comte and Parmesan Reggiano, it can be regarded as desirable
In the evolving cheese matrix, the organisms that will comprise of the (NSLAB) will depend on what conditions
The salt concentration and nutrients present, and which microorganisms are present either (intentionally added or contaminants)
What is organoleptic properties
The sensory properties of the food or chemical including taste, color, appearance, odor, and feel
Producing Swiss cheese
The starter culture used in swiss cheesemaking reduces the pH to a target value that is on the high-end of the pH range for rent coagulated Jesus. The salt level is also deliberately kept low. These conditions high pH - low-salt, and adjustments made by the cheese maker make it ideal for the addition of a secondary culture containing the specific bacterial species Propionibacterium.
What is the role of the starter culture
The term starter culture is derived from the fact that these bacteria "start"the fermentation process required for cheese manufacture. Their primary purpose is to convert lactose in milk to lactic acid. The added starter culture dominates the cheese microbiota, establishing conditions that select for the next microorganisms that will be capable of thriving in the changing cheese matrix. The starter culture also contributes directly to flavor development through production of enzymes and metabolites.
The entrance to a traditional cheese cave in France, part of the caves of the St. Julien in the, Avergne region, used to age St. Nectaire cheese. The cheese caves are hundreds of years old and dug out of volcanic rock
These caves are specially designed and controlled rooms for ripening and aging of cheeses They provide a consistent cool and humid environment suitable for ripening
What makes rennet coagulated cheeses unique
These cheeses results in a gel structure with much lower moisture content, opening the door to almost unlimited possibilities for long-term ripening.
Examples of mesophilic cultures - 105°F or less
These microorganisms ferments lactose only at 105°F or less. Examples include lactobacillus lactic and leuconostic decentralised. Both of which aid in cheddar and Gouda production
What do microorganisms that are part of the secondary microbiota contribute to
They contribute to enzymatic activities that affect the color, flavor, texture and other important characteristics such as the holes in swiss cheese
Can Parmesan Reggianos, English cheddar, and Gruyere support pathogen growth
They do not support the growth of pathogens of correctly manufactured. These cheeses are dry, acidic - low pH - and have a high salt content, all traits that inhibit pathogenic growth
What do microorganisms do in cheese
They transform the natural sugars and proteins in foods such as milk vegetables and grains into a very different food and drink that is even more complex and interesting in flavor
What is rennet coagulation
This depends on the action of the specialized enzymes that, when added to warm milk, around 90°F, can also remove the repulsive forces of the milk proteins again resulting in gel formation
In their native state casein milk proteins repulse one another
This keeps them suspended in liquid . To create cheese, cheese makers generate conditions that overcome these forces, leading the proteins to coalesce and the milk to form a semisolid. This conversion step requires the milk to become more acidic, that is, for its pH to be lowered through the process of fermentation, followed by the coagulation of milk proteins to form a gel
(Color) Depending upon the season and breed of cow, the milk produce contains a variable amount of carotene content
This results in mozzarella cheese appearing yellow. However, when titanium dioxide is added to the cows milk, the resulting mozzarella is whiter, making it look more like water buffalo. Water buffalo milk is naturally white because it contains little or no carotene
What makes acid coagulated cheese unique
This technique involves adding pure acids as a nonstarter culture technique, avoiding reliance on microorganisms altogether paneer is an example
Why are used applied to the outside of cheese
To facilitate ripening they are also known for their neutralizing activity and are commonly applied to the outside of washed rind cheeses to neutralize the surface pH, enabling bacteria such as brevibacterium linens to grow there
Why was cheese,originally made
To preserve and conserve the nutrients and milk, it was typically held for consumption when milk production was reduced during some seasons
Why is milk pasteurized
To remove contaminating pathogens
Technologies used for contamination control in cheese making
Use of phages for food safety. Phages - bacteriophages are the most common microorganisms on the planet and are central for life on earth. These microbes do not directly affect humans, plants, or animals that specifically target bacterial hosts, making them the natural nemesis of bacteria. It is estimated that they just kill nearly half of all the bacteria on earth every two days. And cheese making, phages can be sources of unwanted contamination or can be helpful for controlling contamination. As unwanted contaminants, phages can attack bacteria in the starter culture, thereby preventing acid production and coagulation, resulting in a low acid, low-quality cheese . However they just can also be used to kill specific, unwanted bacterial strains and pathogens that may cause problems for cheesemakers. FDA approved phase cocktails have a specific preference for Listeria. They are applied as a topical spray to food such as cheese and the surrounding environment in which they are being produced, and can be used to prevent listeria contamination . specifically targeting and killing Listeria. And it will not affect other bacterial species used to produce cheese
What is the difference between using a commercial starter culture verses no starter culture
Using no starter culture is a method that is more cost-effective, and produces a cheese that more closely reflects the land from where the milk was collected. She's made without added starter culture encompass traditional rennet coagulated cheeses that rely on natural milk microbiota to achieve the fermentation of lactose to lactic acid.
(Aroma) Common descriptors of cheese are divided into six families
Vegetal, roasted, fruity, lactic, spicy, animal
(Aroma) The distinct aroma of cheese is detected by the nose and is mainly due to a special set of what kind of compounds
Volatile organic compounds (VOC) that result from microbial metabolic activities and enzymatic reactions during cheesemaking and ripening
What are the top five cheese producing states
WI, CA, ID, NM, NY
Name some of the cheese making microbes
Yeast, bacteria, filamentous fungi (molds)
True or false do the three coagulation mechanisms produce gel structure was strikingly different characteristics
Yes they give rise to distinct families of cheeses