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23 Cards in this Set

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Extrinsic factos affecting microbial activity

GPS Route


- Gas composition (21% O, 78% N, .035 Co2, .97


- Presence & activities of m/os


- Storage Temperature


- Relative Humidity

Psychrotrophs growth temperatures:

Min : -5 to +5


Optimal : 25 - 30c


Max: 30 - 35c

Mesophiles growth temperatures

Min: 5 - 15c


Optimal: 30 - 40c


Max: 40 - 47c

thermophiles growth temperature

min: 40 - 45


optimal : 55 - 75


max ; 60 - 90

Two main types of Antagonism

General microbial interference


- competition for nutrients/attachment sites




Lactic Antagonism

Ropiness and sourness in beer are caused by :

Lactobacillus and Acetobacter spp, respectively

Sugar spoilage of confectionary products is caused by :

Bacillus spp

Pickles spoilage, caused by


- Blackening


- Bloaters


- Softening

Bacillus nigrificus


peliococci spp


Bacillus spp

Main causes of food borne disease

Chemical (intrinsic/extrinsic)


Parasites (roundworms)


Phytoplanktons (Domoic acid)


Fungi (Myotoxin producers)


Bacteria (infections)


Viruses (SRSV)


Prions (CJD)

3 Types of Pathogens and examples

• Humans only e.g. s typhi


• Host adopted serovers e.g. abortis ovis, abortis equi


• Unadopted serovers


- no host preference


- Zoonoses



Symptoms of salmonella

Enteritis & Systemic disease (Typhoid)

Enteritis


- Incubation time?


- Infective dose?


- Recovery time?

6 - 48 h


as little as 15 - 20 cells


1 - 3 days

Typhoid


- incubation


- Recovery


- Carry state

3 - 56 days


4 - 5 weeks


months/years

Campylobacter Spp


- incubation


- infective dose


- recovery

2 - 5 days


400 - 500 cells


7 - 10 day recovery




(25% of patients relapse)

How many Staphylococcal Enterotoxins exist?

> 26

Requirements for host invasion?

1. Survive acidic stomach environment


2. Attach to intestine wall


3. Overcome host defence mechanisms


4. Compete with resident GIT microflora


5. Multiply and produce toxins or cross epithelial lining

Cryptosporidium Parvum - 2 main types?

Immunocompetent


- incubation (6 - 14 days)


- recovery (9 - 23 days)




Immunocompromised


- heavy diarroheoa


- Recovery > 30 days

What are the sources and effects of Scombroid poisoning?

Tuna, mackerel, sardines


Burning sensation in mouth, nausea, etc

Puffer Fish poisoning can lead to what, if not dealt with, in 4 - 6 hrs?

death (like guy in Thailand who killed/paralysed half his family by accident! )

What parts of the body to Myotoxins target?

Liver, kidney and immune system

3 important toxigenic species?

aspergillus


fusarium


penicillium

What is the lethal dose of alfatoxin?

0.5 - 10mg/kg

ATBI = ?

Potent hepatocarcinogen