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ACS BOK 1 - Raw Materials, Science, Chemistry
Understanding cheesemaking, types of milk, cheese, pathogens, etc.
88
Culinary Art
Professional
07/01/2013

Additional Culinary Art Flashcards

 


 

Cards

Term
Name the two most common ways to pasteurize milk.
Definition

Heat milk for 30 minutes at a temperature

of 145 F in a vat (most common and method similar to using a double boiler)

 

or

 

Heat milk for 15 seconds at a temperature of 161 F

Term
What is the approximate pH of cow's milk before cultures are added?
Definition

 

 

 

 

6.7

Term
What is the definition of raw milk cheese, according to the raw milk cheesemaker's association?
Definition
Cheese produced from milk that, prior to setting the curd, has not been heated above the temperature of the milk (about 104F) at the time of milking and that the cheese produced from that milk shall be aged for 60 days or longer at a temperature not less than 35F in accordance with US FDA regulations.
Term
When referring to demineralization in cheesemaking, what mineral in milk is being discussed?
Definition

 

 

 

Calcium Phosphate

Term
What are the components of milk?
Definition

Water: 80 - 87% water

Fat

Protein (casein)

Sugar (Lactose)

Vitamins

Minerals

Term
What are the solids in milk?
Definition

Casein (protein)

Lactose (sugar)

Butterfat

Term
What is the approximate solid content in cow's milk?
Definition
12.5%
Term
What is the solid content in sheep's milk?
Definition
19%
Term
What percentage of raw milk contains pathogens?
Definition
7%
Term
What are the times and temps for thermalized milk? (Heat treated milk.)
Definition
145-155 F for 15 to 20 seconds.
Term
List 4 types of lipase.
Definition

Calf lipase

Kid goat lipase

Lamb lipase

Microbial lipase

Term
What happens when you stop the pH at 5.1 in a stabilized brie?
Definition
You get a mild and mushroomy flavor.
Term
What is salt's effect on meltability?
Definition

As the salt level rises, cheese melt is restricted

because salt tightens the

protein network.

 

A saltier cheese, like Parmesan, will

have restricted melt compared with a lower salt

cheese, like Gruyere

Term
What are the principal minerals in milk?
Definition

Calcium and

Phorphorus

in the form of

Calcium Phosphate

Term
List 6 things that make quality milk.
Definition

Lack of odors.

Lack of bacterial growth & contamination.

Composition: casein and fat meets standards.

No antibiotics.

Extemely low sediment.

Healthy animals.

Term
At what tempreature do harder cheeses such as cheddar begin to melt?
Definition
150F
Term
What is the added bacteria in Swiss-style Cheeses?
Definition

Propionibacterium

Shermanii

Term
Why is ash applied to the surface of cheese?
Definition
Ash neutralizes the acidity on the surface of the cheese and that enables a surface-mould to grow, thus altering the maturation characteristics of the interior.
Term
In goat cheese, what causes the primary "goaty" flavor?
Definition
The breakdown of fats
Term
What frequently causes bitterness in cheese?
Definition

The size of the protein

breakdown products.

Term
Why does a cheese become ammoniated?
Definition

The proteins breakdown

faster than the cheese

is able to dissipate the ammonia.

Term
Is all sugar (lactose/galactose) in cheese fermented right away?
Definition

No. After pressing some residual sugar remains:

 

Cheddar: .6%

 

Mozzarella - .8%

 

Parm - up to .8%

Term
Ripening is the result of which micro-organisms and enzymes?
Definition

Bacteria

Yeast

Molds

Proteinases (breakdown of proteins)

Lipases (Breakdown of fats/lipids)

Term
What are the consequences of proteolysis (the breakdown of proteins)?
Definition

Increase in flavor

Loss of stretch or pliability

Smoother body (not curdy)

Softer, pasty body (high moisture cheeses)

Short, crumbly body (Low moisture cheeses; high acid cheeses)

Increase in pH (release of ammonia)

Loss of moisture if cheese is warmed

Term
How do cheesemakers decide to cut the curd?
Definition
They check the consistency.
Term
Why is pH so high in soft-smeared surface ripened cheeses?
Definition

Yeasts like lower pH and higher salt levels in brined surfaces.

 

Yeast metabolizes lactic acid, raising the pH, surface proteolysis starts

 

Micrococci begin to grow more readily

 

B. Linens grow in higher pH, proteolysis continues

Term
Foil does what to cheese?
Definition

1. Controls ripening.

 

2. Air barrier.

Term
Green mold in cheese indicates what?
Definition
Younger age.
Term
What is age effect on meltability?
Definition

The older the cheese, the more its proteins have broken down by cultures and coagulation

 

As it ages, it is less likely to form long strands when melted.

 

Instead it will be shorter and more soupy in texture.

Term
What are the main bacterial types found in milk?
Definition

Psychrotrophic.

 

Bactria that can withstand colder tempratures.

Term
What is water activity as it relates to cheese?
Definition
It is  the measure of the energy status of water in cheese. If WA is below 95 then the cheese is considered "shelf stable" for OOR display purposes. The lower the WA, the longer the shelf life of the product.
Term
What percentage of pathogens is killed with/by thermalization?
Definition
95%
Term
After curd separtion, what are the principal components of whey in order of highest concentration?
Definition
Water, lactose and fat.
Term
What is the pH range for most cheeses?
Definition
4.6 to 6.0
Term
What is the primary concern with regard to mechanical openings in cheese?
Definition
Shelf life and cutting performance.
Term
What is the potential defect caused by excessive lipolysis (breakdown of fat)?
Definition
Rancidity
Term
What bacteria causes the bloomy rind to grow on soft-ripened cheeses?
Definition

Penicillium candidum

Penicillium camemberti

Geotrichum candidum

 

They can be added to the milk during the make or sprayed on after the wheels are formed.

 

Geotrichum does not affect the flavor of the cheese; the other two do.

Term

Name 3 Micro-organisms

Definition
- Bacteria (binary fission)
- Yeasts (multiply by budding)
- Molds (produce spores) 
Term
List 7 raw milk pathogens
Definition

- Listeria Monocytogenes -

Salmonella &

E.coli -

Campylobacter -

Yersinia entercolitica -

Staphylococcus aureus -

Bacillus cereus

Term
What can be used to keep Salmonella & E.coli in check?
Definition
Salt
Term
Why are Phychrotrophic bacteria the main bacterial type found in milk?
Definition
They can live in colder temperatures and thrive in warmer temperatures.
Term
Name 1 of the other main bacteria found in milk and what defines it?
Definition
- Gram positive spore-formers = Bacillus (aerobic) and Clostridia (anaerobic)
- They are resistant to pasteurization
Term
Are starters a microorganism?
Definition
Yes.
Term
What do micro-organisms do?
Definition

- Decompose foods

a. Metabolize sugars and make acids

b. Breakdown fats (produce flavors)

c. Breakdown proteins (produce flavors)

Term
Ripening is the result of the activity of what?
Definition
Micro-organisms and enzymes such as bacteria, yeast, molds, proteinases, lipases.
Term
Name 3 ways to prevent contamination after pasteurization
Definition

- Overall cleanliness -

Sanitation -

Air-handling

Term
Name 4 ways to create conditions in the product that will either kill those microorganisms that are in the finished product or prevent them from growing
Definition

- Acid (low PH) -

Rapidly cool product < 40 f -

Low storage tempertures (40 f or less, especially retail) - Add inhibitors (sorbates, baceriocins (antibiotic), salt)

Term
What is the average make up of protein?
Definition
83% Casein
- 17% Whey proteins
Term
What is microbial rennet made from?
Definition
Mold
Term
What % of cheeses in the US are made using FPC Rennet?
Definition
90%
Term
What is cheese made of?
Definition
- Casein
- Fat
- Water (Whey)
- Sugar (Acids)
- Salt
- Minerals
- Microorganisms/enzymes
Term
Ripening is the result of activity of which microorganisms and enzymes?
Definition
Bacteria
- Yeasts
- Molds
- Proteinases (breakdown protein)
- Lipases (breakdown down lipids)
Term
Why are microorganisms and enzymes deliberately added to ripen cheese?
Definition
Push ripening in the desired direction - Overwhelm the cheese with selected enzymes or microorganisms
Term
List 6 factors that influence enzyme and microorganism activity
Definition
- Temperature/Time (38f or below slows development) - PH (small flucuations make different cheeses) - Cheese composition; salt, moisture, fat content (high moisture cheeses ripen more quickly) - Humidity in room (surface or mold ripened cheese) - Ability to compete in cheese enviroment (oxygen, nutrient availability, competitiveness) - Numbers of bacteria and amount of enzymes (affected by milk quality , cheese handling and heat treatment)
Term
How does pH negatively effect mold ripened cheese?
Definition
Makes it bitter
Term
Are high pH cheeses typically more or less melty?
Definition
Less
Term
How much of cheeses moisture is trapped within its protein network?
Definition
90%
Term
What are some causes of undesired "watering off"?
Definition
- pH (too low or too high)
- Salt (too high)
- Temperature (coupled with low pH or high salt)
- Proeolysis (in a high salt or low pH cheese)
- Freezing/thawing/temperature cycling
Term
Why dilute whey with water?
Definition
Lactose, pH, flavor
Term
What is the active enzyme in rennet?
Definition
The active enzyme in rennet is called chymosin
Term
What is the protein in milk called?
Definition
Casein
Term
Name 3 reasons to pasteurize milk.
Definition

Food safety

Extend transportation time

Extend shelf life of milk.

Term
What is the aging requirement for raw milk cheese?
Definition
60 days minimum
Term
Raw Milk Cheese Production requires responsible and safe practices which include:
Definition

HACCP (Hazard Analysis Critical Control Point)

GMP (Good Manufacture Practices)

Microbial Screening of Raw Milk

FDA limits of SCC (Somatic Cell Counts)

Term
Why is goat and sheep milk cheese whiter than cow milk cheese?
Definition
Goat and sheep convert beta carotene into vitamin A; cows do not.
Term
What happens to lactose in the cheesemaking process?
Definition
Most is lost in the whey; the rest is eaten by cheese cultures and turned into lactic acid.
Term
How does curd size effect the final cheese?
Definition

The smaller the curd; the less moisture in the cheese.

The larger the curd; the more moisture in the cheese.

Term
What is lactic set?
Definition
Cheese made without rennet; allowed to sour and set on its own or with the introduction of citric acid only.
Term
What are temperatures for cooking cheeses by category?
Definition

Lactic set (fresh, bloomy) - 75f

 

Washed Rinds - 75 to 90f

 

Tommes - 90-100f

 

Cheddars - 100-105f

 

Alpine - 105- 115f

 

Grana - 115 - 125f

Term
What is a double-rinded cheese?
Definition
When two different molds introduced to a cheese grow simultaneously on the surface.
Term
Why is lipoysis desirable in hard, Italian cheeses?
Definition
It liberates the short chain fatty acids that contribute to flavor
Term
Which bacterial pathogen has the longest incubation period?
Definition
Listeria monocytogenes
Term
Name a microorganism that is pathogenic to humans?
Definition

Escherichia Coli

(E. Coli)

Term
What is a method to control or prevent bacteriophage in dairy fermentation?
Definition
Rotate phage unrelated starter cultures (this lessens the chance of phage taking hold in the make room from use of the same starter cyltures every time.)
Term
Waht is the proteolytic effect that occurs during the ripening process in hard cheeses?
Definition
Decomposition of proteins caused by natural enzymes, bacteria culture and rennet
Term
What microflora causes the brainy looking rind on surface-ripened cheeses?
Definition
Geotrichum candidum
Term
What is cambium layer?
Definition
The interior section of spruce tree bark, used in strips from wrapping cheeses like Vacherin d'Or.
Term
What are some prerequisites for cheese quality?
Definition

Flavor of the milk.

Low psychrotrophic bacteria numbers.

Somatic cell count (under 250K/ml)

Temperature of the milk (under 40F)

Ag of the milk (less than 60 hours)

Absence of microbial inhibitors

No antibiotics or sanitizers in the milk.

Term
What are the five components of food acceptance?
Definition

Aroma

Taste

Mouth feel

Color and appearance

sound (occasionally)

Term
What happens to beta carotene in regards to milk/cheese?
Definition

Cows do not convert it so it dissolves into the fat globules and the cheese has a yellow color.

 

Goats and sheep convert it into vitamin a whch is colorless so their cheese is white.

Term
3 factors that affect milk quality.
Definition

Breed

Feed

Environment

Term
pH as it pertains to cheese
Definition

0 = highest ph

6.9 would be lowest pH

7 = neutral

 

high calcium phosphate and high initial pH (5-5.4) = Swiss, smear-riped, washed rinds

 

moderate CP and moderate initianl pH (4.95-5.2) includes Cheddar, Colby, Jack, mozz

 

low CP and low initial ph (4.6-4.9) include bloomies, feta, blue, Cheshire.

 

Term
Water activity
Definition

Defines level where food becomes shelf stable and can be OOR.

 

.92-.95 (if pH is OK works)

under .92 - any food id shelf safe.

 

Clostridium boutlinum is the most dangerous food poisoning bacterium and cannot live in food under .93

Term
What adjunct cultures create cheddar flavor?
Definition
l. casei and l. plantarum
Term
What does salt contribute to the cheesemaking process?
Definition

Enhances Flavor

Expulsion of whey

acts in a antimicrobial capacity to preserve cheese from spoilage bacteria and pathogens

 

Term
How does rennet work?
Definition
Snips away kappa-casein from casein. Without the kappas, the remaining caseins clump to gether (coagulate).
Term
At what pH will milk coagulate without rennet?
Definition

4.6

(remember the pH of milk is 6.7 - very low acid)

Term
What is the basic difference between Grad A milk and Grade B milk?
Definition

Grade A has less than 100K count of bacteria

 

Grade b has less than 300K count of bacteria

 

This is all bacteria - good and bad.

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