Industrial toolkit 1

Question 1

What is a processing aid?

Answer 1

Substance that is used for technical effect in food processing. Does not affect intrinsic characterics of the food, and often not detectable.

Question 2

Differences of food additive and processing aid

Answer 2

Food additive: affects characteristics of food, part of food and must be on the label.
Processing aid: NO impact on food characteristics, NOT apart of food, no label declaration and often hard to notice.

Question 3

What is the application of chemical preservatives?

Answer 3

1. Minimize health risk.
2. Improve nutritional quality
3. enhance storage life
4. Improve sensory properties.

Question 4

What is sued for a chemical?

Answer 4

As long as it can inhibit, retard, or arrest decomposition of food.
Add component directly or indirectly to food.
Impairs deterioration by microorganisms.

Question 5

Positives of chemical preservatives?

Answer 5

Very versatile.
-Apply directly to food (Acid)
- Applied to packaging material (mould inhibitors)
-Can be used in water for washing foods (chlorine for veggies)
- Can be added via microorganisms
INDIRECT ADDITION.. biopreservation.

Question 6

Acids: Added directly to food. What is the function? What are commonly used?

Answer 6

Function: flavor, pH modification

acetic and lactic acid most common

Question 7

How do acids work? FIX

Answer 7

pH: log of H ions present
pKa: log of acid dissociation

pH=pKA half is dissociated. @ equilibrium.

WANT acid with pKApH acid will resist dissociation and pH uneffected.
Undissociated acid can enter cell and break enzymes.

Question 8

What microorganisms are vulnerable to acids?

Answer 8

bacteria, yeast and mold.

Question 9

Organic acids (acetic and lactic acid)..tell me about them..FIX

Answer 9

produced naturally during fermentation.

pKa

Question 10

Nitrates importance in food?

Answer 10

Important for food preservation and safety..especially in meats. Adds color and flavor.

Question 11

What microorganism is inhibited by nitrate?

Answer 11

Inhibits outgrowth of endospores C. botulinum

Question 12

What are the allowable limits of nitrates?

Answer 12

200ppm is max,
120ppm in baction. (AA mix with nitrite and cause carcinogens)
100ppm in processed meats.
“rate of addition” never found in cooked meats.

Question 13

How does Nitrite work?

Answer 13

Cells of Clostridium botulinum contain IRON-SULFUR proteins.
Reacts with added nitrite to form iron nitric oxide complexes. This causes destruction of the iron sulfer clusters in enzymes, inactivation of enzymes and growth is inhibited.

Question 14

Active form is nitrous acid HNO2 (pKa 3.4)

Does increasing activity increase when pH is decreased or increased?

Answer 14

Activity increases when pH decreases.
pH >7.5 growth of microorganism
pH 6-7 slight inhibition
pH 5.5-6 some inhibition
4.5-5.5 definite inhibition. (pH of processed meats)
pH <4.5 HNO2 decomposes and pH inhibits bacterial bacterial growth.

Question 15

Common use of nitrate/nitrite?

Answer 15

Processed meats
- Perigo factor (heat + nitrite) 10x increase
Perigo factor is antibacterial factor produced when heat is added to nitrite.
Meat decreases perigo.
With added antimicrobials increases effeciency…less nitrite needed.
ex.
nitrite + erythorbate
nitrite + sorbate

Question 16

What is the risks of nitrite?

Answer 16

carcinogen when nitrite + free amine group.

Question 17

What is the benefits of nitrite?

Answer 17

Controls C. botulinum spores.

Question 18

Nitrate in celery powerder

Answer 18

Must be declared by the manufacturer. Min level is 100ppm. and max is 200ppm.

Question 19

What about natural nitrates?

Answer 19

Not as much control in “natural” nitrates. Nitrate must be converted to nitrite to have microbial effect.

Question 20

Why do we use sulfites in the food industry?

Answer 20

inhibit bacteria, yeast and mold growth. ( found in wines, fruit juices, not allowed in meat b/c destroyed B1)

Question 21

When are sulfites more effective?

Answer 21

When used in low pH, used to be sprayed on salad bars but now considered an allergin.

Question 22

Natural antimicrobial agents

Answer 22

Consumer perception, natural is better.
ex. Lysozyme
avidin found in eggs.
garlic and onions (allicin)

Question 23

BioPreservation..what is it?

Answer 23

exend storage life and enhance safety of foods using the natural microflora and antibacterial products.

Question 24

What is the application of biopreservation in the food?

Answer 24

1. use bacterial strains.
2. Add purified substance
3. add fermentation liquor or concentrate.

Question 25

antimicrobial compounds in LAB

Answer 25

1. Organic acids ( lactic and acetic acid) decrease pH
2. Hydrogen peroxide H2O2
3. CO2
4. diacetyl (flavor of butter)
5. Bacteriocins (antimicrobail peptides)

Question 26

Bacteriocins what are they?

Answer 26

Antibacterial peptides or proteins from bacteria

Question 27

What is the purpose of bacteriocins?

Answer 27

kill or inhibit grow of closely related bacteria. Narrow activity.

Question 28

Classes of bacteriocins

Answer 28

class I (lantibiotics) nisin
- small, heat stable peptides.
- extensive post-translational modification
class II (nonlantibiotics) pediocin, leucocin
- small, heat stable, hydrophobic peptides
- limited post-translational modificatons
Class III
large, hydrophilic proteins
class IV AS-48 carnocyclin
circular bacteriocins

Question 29

What can nisin kill? class I

Answer 29

Listeria spp. C. botulinum, Staph. Aureus NOT gram negatives.

Question 30

What are the benefits of bacteriocin producing LAB?

Answer 30

Natural (consumer acceptance)
production of bacteriocins in food (throughout shelf life)
- Additional hurdle for safety.
- potential replacement ofr chemical preservatives

Question 31

Biosynthesis of bacteriocins…must have?

Answer 31

Must have structural genes (immunity genes)

May require: transport genes (modifation and regulation genes)

Question 32

Class i: Lantibiotics

Answer 32

Ribosomally synthesized, produced as pre-petides, and undgergo post-translational modifcations.

Question 33

A little about Nisin

Answer 33

liscensed in over 50 countries.

Produced by Lactococcus lactis susp. lactis

Question 34

What is the application of Nisin in food?

Answer 34

UHT milk, canned veggies, pasteurized processed cheese, dariy and liquid egg products.

Question 35

what causes the inactivation of nisin?

Answer 35

reactions with surfaces and meat components. Poor solubility, sensitivte to food enzymes, high bacterial loads (like growing by itself), interaction with phospholipids, and poor distribution throughout the product.

Question 36

Class II nonlantibiotics

Answer 36

Micocin: commerically available. from carnobacterium maltaromaticum. prodcues three bacteriocins.

Question 37

What does micocin do with L. monocytogenes

Answer 37

It decreasese the log numbers increasingly. Overcomes hurdles.

Question 38

Plant extracts as antimicrobials: 2 popular ones

Answer 38

1. Allyl isothiocyanates: mustard/horseradish
inhibits bacterial growth on foods
E.coli uncooked ham
Listeria ground beef
Salmonella- ground beef
or adds flavor. 
2. Rosemary extract. 
strong flavor acts as antioxidant and antimicrobial.