Fermented Milk Products Quiz

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Questions and Answers

What type of milk is primarily used to prepare fermented milk products?

Goat milk

Buttermilk

Skimmed milk (correct)

Whole milk

Which microorganisms are primarily responsible for the fermentation of dairy products?

Bacteria and molds

Lactic acid bacteria (correct)

Viruses and yeasts

Yeasts and molds

What influences the nature of fermented milk products?

Only the type of milk used

Only fermentation temperature

The type of packaging used

Pre-treatment of milk and fermentation conditions (correct)

Which of the following is NOT a category of fermented milk products?

Fruity yogurt types Signup and view all the answers

What is the role of starter cultures in the production of fermented milk products?

To provide a defined mixture of microorganisms Signup and view all the answers

Which fermented product is characterized by a sour taste and pleasant aroma?

Yogurt Signup and view all the answers

What does the term 'multiple-strain starter cultures' refer to?

Undefined mixtures of different bacterial types Signup and view all the answers

What is the main product of the fermentation process in fermented dairy products?

Lactic acid Signup and view all the answers

What is the primary function of the bacteria Lactobacillus bulgaricus and Streptococcus thermophilus in yogurt production?

To help culture the milk and contribute to flavor and acidity Signup and view all the answers

At what temperature range should inoculated milk be incubated for yogurt production?

42-46°C Signup and view all the answers

Which bacterial strain initiates the fermentation process in sauerkraut?

Leuconostoc mesenteroides Signup and view all the answers

What is the main characteristic of sauerkraut fermentation in terms of salt concentration?

Between 2% and 3% salt is needed Signup and view all the answers

Why is it detrimental for the pH to decrease during sauerkraut fermentation?

It inhibits the growth of bacterial species Signup and view all the answers

What type of fermentation stage follows the initial heterofermentative stage in sauerkraut production?

Homofermentative stage Signup and view all the answers

What is the primary biochemical change that occurs during fermentation?

The breakdown of organic substances by microbial enzymes Signup and view all the answers

What occurs if the temperature exceeds 72°F (22°C) during sauerkraut fermentation?

Bacterial growth may be inhibited, leading to off-flavors Signup and view all the answers

Which end products are produced by Leuconostoc mesenteroides during fermentation?

Lactic acid, acetic acid, and carbon dioxide Signup and view all the answers

Which nutrient is NOT typically produced during the fermentation process?

Vitamin D Signup and view all the answers

Which of the following is a benefit of consuming fermented foods?

They help in improving immunity Signup and view all the answers

What process is primarily involved in preserving fermented foods?

Lactofermentation Signup and view all the answers

Which food is an example of a fermented product?

Kefir Signup and view all the answers

What is a crucial role of probiotics in the digestive system?

They help maintain the balance of gut bacteria Signup and view all the answers

What happens to raw milk when it is kept at room temperature for too long?

It spoils and becomes sour due to lactic acid bacteria Signup and view all the answers

Why are fermented foods considered a cheaper source of nutrients?

They have a longer shelf life without nutrient loss Signup and view all the answers

What potential health benefit is associated with the consumption of certain lactobacilli?

Reduced blood pressure in mildly hypertensive individuals Signup and view all the answers

How do probiotics potentially prevent food allergies?

By reinforcing the barrier function of the intestinal wall Signup and view all the answers

What is a primary characteristic of kefir?

It is rich in vitamins and minerals, including phosphorus and calcium Signup and view all the answers

What role do lactic-acid producing microorganisms play in the fermentation process?

They produce lactic acid, enhancing milk acidity Signup and view all the answers

Which bacteria is utilized as a starter culture in the production of sour cream?

Streptococcus lactis Signup and view all the answers

What differentiates soft and hard cheeses during production?

The duration of milk culturing Signup and view all the answers

Which mineral is NOT mentioned as being abundant in kefir?

Iron Signup and view all the answers

Which factor affects the composition of cheese?

The type of milk (fat fraction) used Signup and view all the answers

What is the primary purpose of adding sodium ascorbate or ascorbic acid during the processing of fermented sausages?

To prevent oxidation and improve color stability Signup and view all the answers

What role do glucose solids (dextrose) play in the processing of certain meat products?

They facilitate browning reactions and caramel flavor. Signup and view all the answers

What conditions are most important for the fermentation of sausages?

High humidity and controlled temperature Signup and view all the answers

Which of the following indicates a potential defect in fermented meat products?

Presence of white spots on the surface Signup and view all the answers

What effect does controlled smoking have on fermented sausages?

It minimizes production of polycyclic hydrocarbons. Signup and view all the answers

What could cause discoloration on the inside of the sausage?

Insufficient curing salt or oxygen removal Signup and view all the answers

Which of the following is NOT a common defect of fermented sausages?

Strong and pleasant flavor development Signup and view all the answers

What temperatures are typically used for controlled combustion in smoking fermented sausages?

300-600 °C Signup and view all the answers

What is the primary purpose of treating green olives with a diluted lye solution?

To eliminate oleuropein and prepare for fermentation Signup and view all the answers

Which microorganisms are primarily responsible for the fermentation of treated olives?

Lactic acid bacteria (LAB) Signup and view all the answers

What is the consequence of the pH of brine reaching 4.5 during fermentation?

Lactobacillus plantarum becomes predominant Signup and view all the answers

In which processing method are both fermentation and alkaline treatment used?

Spanish type processing Signup and view all the answers

Why must fresh green olives be processed quickly after harvesting?

They undergo spoilage rapidly Signup and view all the answers

What type of containers have been more recently used for the fermentation of olives?

Larger inert-coated containers Signup and view all the answers

Which species of Lactobacillus is not predominantly found in most olive fermentations?

Lactobacillus sakei Signup and view all the answers

What is the typical concentration of brine used during the fermentation of olives?

9-10% Signup and view all the answers

Study Notes

Fermented Foods

Fermentation is a biochemical change in organic substances, resulting from microbial enzyme action.
Fermented foods undergo lactofermentation, where natural bacteria consume sugars and starches, creating lactic acid.
Fermentation preserves food and produces beneficial enzymes, B-vitamins, Omega-3 fatty acids, and probiotics.

Fermented Dairy Products

Milk is a white liquid produced by mammary glands, serving as the primary nutrition source for young mammals.
Raw milk, if kept at room temperature, is prone to microbial spoilage and souring from lactic acid bacteria.
Fermented milk products like yogurt, curd, and kefir are defined as milk products made from skimmed or whole milk, with or without microbial cultures.
Various types of fermented milks and derived products differ by milk type, pre-treatment, fermentation conditions, and subsequent treatments..
The propagation of microorganisms can occur as multiple-strain starter cultures or a mixture of different types of bacteria.

Nutritional Benefits of Fermented Milk Products

Lactic acid bacteria (like Lactobacillus) protect against pathogens and gastrointestinal infections
Lactic acid bacteria have anti-cancer effects; they improve immune responses, change faecal enzymes, and reduce the mutagenicity of chemical mutagens.
Milk supplemented with lactic bacteria helps lactose digestion for those with lactose intolerance. This is because the bacteria in yogurt produce lactase, a digestive enzyme for lactose.

Fermentation Process

Fermented dairy products are made from milk, milk products, and microbial starters.
Different types of milk products can be used.
Varying fermentation temperatures and times produces varieties of fermented dairy products and flavors.
Temperature and time vary between individual products.

Fermented Vegetables Overview

Sauerkraut is made by lactic acid bacteria fermenting cabbage with salt.
Sauerkraut is fermented through heterofermentative and homofermentative stages.
The quality of sauerkraut is affected by the fermentation temperature (optimum is 65-72° F or 18-22° C).
Higher temperatures make sauerkraut faster but with lower quality., while lower temperatures are slower.
Temperature and time duration are crucial for the fermentation process.
Salt inhibits certain microorganisms but allows for the growth of lactic acid bacteria that are necessary for the fermentation process

Sauerkraut Fermentation

Leuconostoc mesenteroides begins fermentation, creating lactic acid, acetic acid, ethyl alcohol, and carbon dioxide.
Lactobacillus plantarum continues fermentation using the metabolites from Leuconostoc.
Optimal fermentation happens at low temperatures (18-22°C), the optimal temperature and time should be met for the ideal quality of sauerkraut. Off-flavors may develop with higher temperatures.

Olives

Green olives undergo two primary processing methods: with or without fermentation.
The treatment process for green olives can use lye to modify and transform chemical compounds and sugars.
Fermentation uses lactic acid bacteria which leads to different flavors and aromas.
Different types of bacteria may lead to spoilage of the olives and the quality of the olives.

Pickles

Fermented pickles use cucumbers supplemented with salt and spices.
Pickles are fermented in low-salt brines for taste acceptability with shorter shelf lives.
Adding vinegar during commercial production extends shelf-life.
Fermentation speed depends on temperature and brine strength.
Leuconostoc mesenteroides is the preferred starting organism.
Lactic acid accumulates creating the appropriate conditions to favor Lactobacillus fermentation.

Fermented Meat

Meat fermentation is a low-energy method enhancing flavor, palatability, color, safety, and tenderness.
Fermentation uses cultured or wild microorganisms which lower the pH of the raw meat.
Traditional meat preservation methods use salting, drying, or smoking.
Lower water activity from salting, and drying improves shelf-life.
Sausages are the most crucial product from fermented meat with four major categories, varying by preparation methods.

Fermented Sausages

Microorganisms in sausages are limited with defined categories based on production, physical, and chemical characteristics.
Fermentation uses a mixture of lean and fat meats, additives, and seasonings stuffed into natural or artificial casings.
The desired characteristics (like flavor, texture, color) depend on temperature, humidity, air velocity, fat/sodium content, and casing type.
Different types of bacteria and yeasts may ferment, dry cure, and shape fermented meat products and sausages.

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Description

This quiz tests your knowledge of fermented milk products, including the microorganisms involved in their production and the conditions necessary for fermentation. From understanding starter cultures to the importance of specific bacteria, assess your expertise in dairy fermentation processes.