Food and Industry

Question 1

How is bacteria introduced into raw milk/

Answer 1

Normally sterile before it is drawn from the cow.

Raw milk has bacteria introduced via the equipment, workers or infected animals

Question 2

What bacteria are found in raw milk?

Answer 2

Lactococci, Pseudomonas, Alcaligenes, Flavobacterium.

Question 3

What causesmilk to sour?

Answer 3

Souring of milk caused by, Lactococcus lactis. A homofermentative bacterium

Question 4

What bacteria do workers contaminate milk with?

Answer 4

Workers:Salmonella, Corynebacterium, Shigella.

Question 5

What bacteria do infected animals contaminate milk with?

Answer 5

Brucella abortus, undulant fever; Coxiella burnetii, Q fever.

Question 6

How is raw milk preserved?

Answer 6

Pasteurized by low temperature holding, high temperature short time. . These methods destroy all non spore forming pathogenic bacteria and many non pathogenic bacteria in raw milk.
Ultra high temperature: milk can be stored without refrigeration for months

Question 7

WHat is LTH?

Answer 7

LTH: low temperature holding, 62.8 C for 30 min.

Question 8

What is HTST?

Answer 8

HTST: high temperature short time,71.7 C for 15 sec.

Question 9

What is UHT?

Answer 9

ultra high temperature, 137.8 C for a few seconds, then placed in sterile container, milk can be stored without refrigeration for months

Question 10

What is a phosphatase test?

Answer 10

An enzyme in Raw milk that is destroyed by pasteurization. Therefore the absence of this enzyme in raw milk means the raw milk was pasteurized properly

Question 11

WHat does the enzyme phosphate degrade?

Answer 11

disodium phenylphosphate to phenol and sodium phosphate.

Question 12

How are fermented milks and milk products accomplished?

Answer 12

a variety of lactic acid bacteria used as (Starter Cultures)

Question 13

How is yogurt produced

Answer 13

Made from whole milk. Supplemented with skim milk powder. This gives protein –gel structure of the product. Raw materials are heated and cooled. Inoculation with Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus. In a ratio 1:1. The strep produces the acid, the lactobacilli produces the flavor. Possible to add probiotics to the mixture.

Question 14

What types of butter are there?

Answer 14

sweet cream and cultured butter

Question 15

How is cultured butter made?

Answer 15

pasteurized cream ripened with bacteria 24-48 hrs prior to churning. Lactococcus lactis ssp. diacetylactis, Leuconostoc citrovorum, are used. This produces diacetyl the butter note, in butt

Question 16

How is cheese produced?

Answer 16

No standard method:
Pretreatment of raw milk (pasteurization, culturing)
Formation of solid curd (rennet enzyme addition)
Removal of the liquid whey from the curd
Curd processing ( cooking, washing, milling, salting)
Ripening and ageing

Question 17

What do different cheeses depend on?

Answer 17

Type of milk used.
Diet of milk producer.
Particular strain of starter culture used.
Processing methods used.
Environmental conditions used during ripening, temperature, humidity.

Question 18

What types of cheese are there?

Answer 18

Soft unripened, soft ripened 1-5 months, semi soft ripened 1-13 months, hard ripened 1-12 months, very hard ripened 12-18months

Question 19

What makes soft unripened cheese?

Answer 19

Cottage, Lactococcus lactis, Leuconostoc citrovorum.
Cream, Lactococcus cremoris.
Mozzarella, Lactobacillus bulgaricus, Streptococcus thermophilus.

Question 20

What makes soft ripened cheese?

Answer 20

Brie, Lactococcus lactis, Leuconostoc cremoris

Question 21

What makes semi soft cheese?

Answer 21

Roquefort (ripened 1-12 months)

Lactococcus lactis, L. cremoris, Penicillium roqueforti.

Question 22

What makes hard cheese?

Answer 22

Lactococcus lactis, Lactobacillus casei, Lactococcus cremoris

Question 23

What makes very hard cheese?

Answer 23

), Parmesan,

Lactococcus lactis, Lactobacillus bulgaricus, Lactococcus cremoris, Streptococcus thermophilus.

Question 24

How are fermented meats processed?

Answer 24

Cut meat, add spices, add starter culture: Pediococcus acidilactici, Staphylococcus carnosus. Fermentation occurs, pH drops below 5.0, Add nitrites to control Clostridium botulinum

Question 25

What are fermented meats?

Answer 25

dry sausage: pepperoni, salami

Question 26

How are meats preserved?

Answer 26

Raw meat stored at 5 C for 3-10 days, or at 0 C for 30 days. Growth of psychrophiles is not prevented, Pseudomonas sp

Question 27

What does dehydration do?

Answer 27

Dehydration, jerky, reduces moisture, prevents growth of bacteria

Question 28

What agents are included in dehydration and curing?

Answer 28

these agents include sodium nitrate, sodium nitrite, lowers water activity of the meat, nitrite inhibits Clostridium botulinum. Nitrate gives meat a red color.

Question 29

Where are fermented fish seen?

Answer 29

sauces and pastes, seen in SE Asia, whole, chopped, mashed fish and shrimp.

Question 30

How are fermented fish preserved?

Answer 30

Salt and sealed in vessels.Flavourings added, natural microflora, natural fermentation. Normally strains of S. carnosus. Mam-tom of China, mam-rouc of Cambodia. Ratio 1:3 salt to fish.

Question 31

How is chicken spoiled?

Answer 31

Spoilage in chicken, processing, usually Pseudomonas. In chicken houses Salmonella

Question 32

How are chicken eggs spoiled?

Answer 32

. Chicken egg is infected via, cracks in the shell, and ovarian infection, both have Salmonella involved

Question 33

How are canned foods preserved?

Answer 33

heating canned goods at a high temperature long enough to destroy spores of Clostridium botulinum. 100 C for foods with pH below 4.0, 121 C for foods with a pH above 4.5.

Question 34

What is in indicator of heat resistant spores?

Answer 34

Bacillus stearothermophilus is a QC indicator test organism

Question 35

What are types of fermented foods?

Answer 35

Beer, Bread, Sourdough Bread, Olives, Pickles, Soy sauce

Question 36

How is sauerkraut made?

Answer 36

Wilted shredded cabbage mixed with 2-3% salt. Natural fementation in large tanks, Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides, are observed in the growth until acid level reaches 1.0%, lasts 20-30 days at room temperature, acid reaches 1.5%.

Question 37

What are probiotics?

Answer 37

Are bacteria that promote development and maintenance of balanced intestinal flora

Question 38

What are types of lactic acid bacteria?

Answer 38

Lactic acid bacteria: Lactobacillus acidophilus, L. casei and Bifidobacterium bifidum.

Question 39

Where is lactic acid bacteria added?

Answer 39

Added to fermented dairy products yogurt “Activia”. Effects include stimulating the immune response, often see a stimulation in the production of IgA. Often given to farm animals as well.

Question 40

How is bread made?

Answer 40

Involves the use of yeast to leaven cereal products to generate CO2 which makes the dough rise. Saccharomyces cerevisiae, ferments the sugars make carbon dioxide.