L11 - Food Poisioning Flashcards Preview

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Flashcards in L11 - Food Poisioning Deck (13):

Briefly state the stages in cheese production

1) Bacteria ferment lactose in milk to lactic acid
2) the pH drops causing the protein casein to precipitate out
3) Solid matter separates from liquid; curds and whey. Solid is compressed to form cheese
4) flavour is added my microorganisms


What microorganism is used to make each type of cheese?
a) Limburger
b) Brie, Camembert
d) Roquefort, Stilton, Danish Blue
e) Swiss and Emmental

a)Brevibacterium linens
b) Penicillium camemberti
c)Penicillium roqueforti
d)Propionibacterium shermanii


How does yeast in bread production produce CO2

Amylases in the flour break down starch to glucose, which the yeasts use as fuel for aerobic respiration producing H2O and CO2, and some ethanol anaerobically


What is the proper name of the yeast microorganism?

Saccharomyces cerevisiae


Briefly state the stages in beer production

1) cereals (barley) are allowed to germinate (malting) so that they contain the enzymes to breakdown starch
2) malted grains are mashed with warm water. Enzymes break down starch to maltose and glucose
3) Clear liquid is removed and boiled with hops
4) Yeast is later added to ferment the sugars to alcohol


What is top and bottom fermentation?

Top fermentation: Yeast does not settle, produces beer. Fermentation at 14-23 ºC in 5-7 days. Stored at 4-8 ºC

Bottom fermentation: Yeast settles to bottom of fermentation vat which produces lager. Fermentation at 6-12ºC in 8-14 days. Stored at –1ºC for several weeks before packaging


What is the most common symptom of food poisoning?



What is the difference in food poisoning caused by intoxication and infection?

Intoxication - caused by the toxins produced by bacteria. Live bacteria do not need to be ingested. Toxins are exotoxins such as enterotoxin or neurotoxin

Infection - 2 types:
1) ingested bacteria doesn't need to grow in the gut
2) ingested bacteria does need to grow and multiply in the gut


Describe a) enterotoxin b) neurotoxin

a) enterotoxin - causes enterocytes in the cut to release H2O and Na+ causing diarrhoea. can also tell the brain to cause vomiting
b) neurotoxin - passes through the wall of the gut into the blood and attaches to nerve endings in tissues causing paralysis


What kind of toxin causes the symptoms caused by Staphylococcus aureus?



What symptoms does Campylobacter cause?

Flue like, diarrhoea, vomiting, lasting 2-5days


What are the symptoms of pathogenic E.coli?

Diarrhoea with bleeding, internal bleeding in the brain


Where is E.coli found?

The gut of cattle