Test 1.1

Question 1

Salmonella General characteristics.

Answer 1

• G (-) Rod.
• Fac. Anaerobe.
• Non- motile.
• Selective enrichment needed ( Na- selenite, cysteine).
• T: 35- 27.
• pH 7 - 7.5.
• Opt H2O .99, but range.

Question 2

Salmonella decomposition.

Answer 2

• Lactase, Urease, Sucrose, Indole, Vogues Proskauer -ve.
• Glucose +ve.
• H2S prod +ve.

Question 3

Salmonella Resistance.

Answer 3

• Well on food surface 28 d in refrigeration.

- pH less resistant vs e. coli.

Question 4

Salmonella Inactivation.

Answer 4

• Freezing = but doesn’t ensure total inactivation.
• Heat = 60 2- 6 min, 70 1 min.
• pH= can ø grow in pH 5.1.
• Low Aw = reduced growth.

Question 5

Salmonella Illness.

Answer 5

• Incubation= up to 48hrs but usually within 16.
• CS: Abd pain, vomit, diarrhoea for about a wk, self limiting, low mt.
• Long term = Septicemia and reactive arthrities.
• Source - PO, shed through feces, contamianted meat, egg, dairy product.

Question 6

E. coli General Characteristics.

Answer 6

• G (-) rod.
• Fac anaerobe.
• OKHF Ag.
• T 37 ( range).
• pH EHEC can grow down to 4.4 aW= .95.

Question 7

E.coli Decomposition.

Answer 7

• • lactose, Indole, Methyl red.

- VP, citrate.

Question 8

E.coli Resistance.

Answer 8

Medium.

Question 9

E.coli Inactivation.

Answer 9

Cook all parts to >70.

Question 10

Campylobacter General Characteristics.

Answer 10

• Curved G (-) rod.
• Fastidious - blood agar.
• Microaerophilic 3.6% O2 + 10% CO2 needed for growth.
• Thermophilic - opt 42, min 30.
• Selective culture with vanco, poly + trimethprim.

Question 11

Campylobacter Decomposition.

Answer 11

• • Oxidative.

- Does ø split carbs, E demands met through utilisation of protein AA + organic acids.

Question 12

Campylobacter Resistance.

Answer 12

• Weak poor survival in environment but likes humid temp.

- Likes meat/ hand surface.

Question 13

Campylobacter Inactivation.

Answer 13

• Heat 55º for 5 mins.

Question 14

Campylobacter CS.

Answer 14

• Most common bacterial infection in Hu.
• Contamination via milk, on meat surface.
• Incubation 1 - 10 D.
• M. pain, fever, diarrhea, nausea.
• Reiter Syn - autoimmune “ Can’t see, can’t pee, can’t climb a tree”.
• Guillian Barre Syn- acute polyneuropathy affecting PNS.

Question 15

Listeria General cahracteristics.

Answer 15

• G+ rod, ciliated at 22ºC, can become + IC.

- Selective enrichment cold U tube.

Question 16

Listeria Decomposition.

Answer 16

• • B hemolysis, CAMP test, Rhamnose.

- Oxidase.

Question 17

Listeria Resistance.

Answer 17

• High.
• pH = down to 4.4 need organic acid to kill.
• Fridge down to 0 º.

Question 18

Listeria Inactivation.

Answer 18

• Boil 5 min at 60.

- Rapid pasteurization.

Question 19

Listeria CS.

Answer 19

• Source is raw milk + milk products ( can survive ripening).
• Flu like but care in pregnant causes abortion, fetopathogen.
• CNS symptoms possible.

Question 20

S. aureus General Characteristics.

Answer 20

• SPherical G +.
• Fac anaerobe.
• Mesophile.
• Halophile can tolerate <20% NACl.
• ø fastidious.
• Makes heat stable toxins, danger, MRSA.

Question 21

S. aureus Decomposition.

Answer 21

• 30% are coagulase +ve.

Question 22

S. aureus Resistance.

Answer 22

• Good, mnths in dry env.

Question 23

S. aureus Inactivation.

Answer 23

UV light sterilization.

Question 24

S. aureus CS.

Answer 24

• Contaminated meat + dairy products, ø kept hot/ cold enough.
• Acute symptoms in hrs.
• Diarrhea, vomit, pain, suppurative inflammations inanimals ( mastitis, sept, arthritis, derm), mastitis strains only rarely in milk.
• Animal strains do ø infect people + vice versa.

Question 25

Botox General Characteristics.

Answer 25

• Anaerobic G
• Spore forming.
• Differentiated by toxins in humans A, B + E.
• Toxins cause the inhibition of neurotransmitter AcH release causing a flaccid paralysis.

Question 26

Botox Resistance.

Answer 26

• Spore is very high, resistant to heat, radiation, ionisation.
• Veg are sensitive.

Question 27

Botox Inactivation.

Answer 27

Heat to 80 for 10 mins or more.

Question 28

Botox CS.

Answer 28

• Acute disease, death may be without signs due to paralysis of m. + heart.
• For animals carrion in stomach + hemorrhages in GI is suspect, condemnation of carcass.

Question 29

C. Perfringens General Characteristics.

Answer 29

• G+ rod.
• Spore forming.
• A- E enterotoxins.
• Opt T 43- 47.
  pH lowest is 5, opt 6 - 7.5.

Question 30

C. perfringens resistance.

Answer 30

• Spore is very high

- Veg low, sensitive to acids + salts.

Question 31

C. perfringens CS.

Answer 31

• Acute, from contaminated food esp meat, spores are in cont environment.
• Nausea, pain, H2Ory diarrhea, self- limiting ø tx needed.

Question 32

C. perfringens inact/ prevention.

Answer 32

• Consume prepared foods quickly/ cool to < 10 within 2 - 3 hrs.

Question 33

Bacillus Cereus.

Answer 33

• G+ rod.

- Spore forming.

Question 34

B. cereus Inactivation.

Answer 34

• Diarrhea form: 55º for 5 min causes fever + H2Ory diarrhea.
• Emetic form: peptide toxin, inactivate by 126º for 90mins, binds to 5HT R leading to stim of vagus found in rice + pasta.