The purpose of weighting down the cabbage in a sauerkraut vessel is to
Answer: C
A weight or follower holds the shreds under the liquid so that no surface is exposed for moulds and film yeasts to colonise. Gas is meant to escape, and neither temperature nor further juice extraction depends on the weight.
Please log in or register to report this question.
Which is the correct order of events in a sauerkraut fermentation?
Answer: D
Salt is added first and draws out the juice that forms the brine, the bacteria then acidify that brine, and the product is stable once the acidity is high enough and the sugar has gone. No other order is physically possible.
Please log in or register to report this question.
If sauerkraut smells strongly of rotting rather than sour, the most likely explanation is
Answer: A
Correct answer: Spoilage organisms grew because acid formed too slowly
Preservation is a race: the lactic acid bacteria must drop the pH before the putrefactive organisms establish themselves. Too little salt, too low a temperature or too coarse a shred all slow the acid production and let the competitors win, which is what a rotten smell records.
Please log in or register to report this question.
Pickles described as sour, dill or sweet differ mainly in
Answer: B
Correct answer: How the fermented stock is finished and seasoned
All three begin as the same fermented salt-stock. The difference is what is done afterwards - vinegar for sour, dill and spices for dill, and a sugar syrup for sweet. The fermentation itself is common to them, which is why the distinction is one of finishing rather than of process.
Please log in or register to report this question.
Which is true of the carbon dioxide produced during vegetable fermentation?
Answer: C
Gas from the heterofermentative stage is expected and useful, since it blankets the surface and keeps air away. In cucumbers the same gas causes bloating if it cannot escape, which is a problem of control rather than of contamination.
Please log in or register to report this question.
Fermented vegetables keep well at room temperature mainly because their pH is
Answer: D
Correct answer: Low enough to stop spoilage bacteria growing
A pH below about 4 prevents the growth of nearly all spoilage bacteria and of every food poisoning organism, including Clostridium botulinum. That is the whole basis of preservation by fermentation, and it is why the pH rather than the taste is the measure that matters.
Please log in or register to report this question.
Which vegetable is fermented to make kimchi?
Answer: A
Kimchi is most often made from Chinese cabbage, salted and seasoned before fermenting. Its microbiology parallels sauerkraut closely, with Leuconostoc leading the early stage before more acid-tolerant lactobacilli take over.
Please log in or register to report this question.
The term brining, applied to cucumbers, means
Answer: B
Correct answer: Immersing them in salt solution to ferment
Brining puts the cucumbers into salt solution, where the salt draws out their juice, suppresses competing organisms and permits the lactic acid bacteria to work. The word describes the whole fermentation process rather than merely the addition of salt.
Please log in or register to report this question.
Which condition is NOT required for a successful sauerkraut fermentation?
Answer: C
Correct answer: Continuous stirring to aerate the vat
Aeration is the one thing that must not be done: the lactic acid bacteria are anaerobic or facultative, and admitting air favours the film yeasts and moulds instead. Excluding air, providing sugar and using the right salt concentration are all genuine requirements.
Please log in or register to report this question.
Lactic acid bacteria obtain their energy in a vegetable fermentation by
Answer: D
Correct answer: Fermenting the sugars present in the vegetable juice
The bacteria ferment the sugars released from the cabbage or cucumber into lactic acid, and it is that acid which preserves the product. They obtain no energy from salt, cannot photosynthesise, and do not attack pectin - pectin breakdown is a spoilage process that softens pickles.
Please log in or register to report this question.
