Toxins and pesticides

Question 1

What is Phtohaemagglutinin and where is it found?

Answer 1

A lectin found in plants and legumes

Question 2

What does Phytohaemagglutinin do?

Answer 2

Induces cell mitosis and effects cell transport functions

Question 3

What are Ribosome Inactivating Proteins (RIPs)?

Answer 3

Catalytic toxins

Question 4

What do RIPs do?

Answer 4

One part targets and mediates entry, the other modifies rRNA

Question 5

What is the difference between endotoxins and exotoxins?

Answer 5

Endotoxins are cell bound and released in large amounts
Exotoxins are released from the cell as it grows by enzymes

Question 6

What are the 3 fungal species?

Answer 6

Aspergillus spp
Penicillium spp (rot)
Fusarium spp

Question 7

What does toxicity depend on?

Answer 7

Toxicity of substance
Dose
Biology of organism
Chemical properties of substance

Question 8

What is ADI?

Answer 8

Acceptable daily intake= No observable adverse effects/100

Question 9

What is tolerance level?

Answer 9

ADI/Daily food intake

Question 10

What are moulds and yeasts susceptible to?

Answer 10

Weak acids

Question 11

What do strong acids do?

Answer 11

Give sour flavour and cause extracellular effects

Question 12

What acid is used for total dissociation of moulds and yeast?

Answer 12

Both acids

Question 13

What increases as fatty acid chain length increases?

Answer 13

Antimicrobial activity

Question 14

What esters are found in foods?

Answer 14

Alkyl esters ranging from C1 to C7

Question 15

What happens when ester length increases?

Answer 15

Increases hydrophobicity and potency

Question 16

What are esters potent against?

Answer 16

Gram positive bacteria

Question 17

What is the role of sulphites?

Answer 17

Antioxidant, reducing agent
Effective against yeasts and gram negative bacteria
Better in low pH

Question 18

What are sulphites formed from?

Answer 18

Disulphite anion

Question 19

What are the intracellular effects of sulphites?

Answer 19

Protein disruption
Degrades ATP and NADP
Interacts with DNA and RNA

Question 20

What does sulphite also effect?

Answer 20

Enzymes and unsaturated lipids

Question 21

What is the role of nitrates?

Answer 21

Primary defence against bacteria for meat and fish

Question 22

What is active packaging?

Answer 22

Addition of reactive chemicals

Question 23

What is oxygen scavenging?

Answer 23

Using Fe to remove O2

Question 24

What is hurdle technology?

Answer 24

Combination of sub-lethal challenges to achieve safety (pH, temperature, Aw)