Yogurt Microorganism Summary

What are the two main types of bacteria used in yogurt production?

• Pseudomonas aeruginosa and Clostridium difficile

• Bacillus subtilis and Staphylococcus aureus

• Lactobacillus bulgaricus and Streptococcus thermophilus

• Escherichia coli and Salmonella enterica

Which bacteria is responsible for the fermentation process in yogurt?

• Staphylococcus aureus

• Lactobacillus bulgaricus and Streptococcus thermophilus

• Escherichia coli

• Salmonella enterica

What is the ideal temperature range for yogurt fermentation?

• 70°F - 75°F (21°C - 24°C)

• 110°F - 115°F (43°C - 46°C)

• 90°F - 95°F (32°C - 35°C)

• 120°F - 125°F (49°C - 52°C)

What are the benefits of yogurt cultures and probiotics?

• Yogurt cultures and probiotics provide several benefits such as improving digestion, boosting the immune system, promoting a healthy gut, and reducing the risk of certain infections.

• Yogurt cultures and probiotics are only beneficial for children.

• Yogurt cultures and probiotics can cause digestive problems.

• Yogurt cultures and probiotics have no benefits.

Which bacteria strain is commonly used as a starter culture in yogurt production?

• Streptococcus thermophilus

• Escherichia coli

• Salmonella enterica

• Lactobacillus bulgaricus

What is the role of lactic acid bacteria in yogurt fermentation?

• Lactic acid bacteria convert lactose into lactic acid and contribute to the taste, texture, and preservation of yogurt.

• Lactic acid bacteria increase the acidity of yogurt during fermentation.

• Lactic acid bacteria break down proteins in yogurt fermentation.

• Lactic acid bacteria produce carbon dioxide during yogurt fermentation.

What is the difference between mesophilic and thermophilic yogurt bacteria?

• The main difference is the type of milk used.

• The main difference is the fermentation time.

• The main difference is the pH level required.

• The main difference is the temperature at which they thrive.

How do yogurt cultures contribute to the texture and flavor of yogurt?

• By fermenting the milk and converting lactose into lactic acid.

• By thickening the yogurt with gelatin.

• By adding sugar and artificial flavors.

• By increasing the protein content of the yogurt.

What are some common probiotic strains found in yogurt?

• Lactobacillus plantarum, Bifidobacterium longum, Streptococcus mutans

• Lactobacillus rhamnosus, Bifidobacterium infantis, Streptococcus pyogenes

• Lactobacillus acidophilus, Bifidobacterium lactis, Streptococcus thermophilus

• Lactobacillus casei, Bifidobacterium breve, Streptococcus salivarius

What factors can affect the growth and activity of yogurt bacteria?

• Color of the container, brand of the yogurt, amount of sugar added

• Humidity, altitude, type of spoon used

• Presence of music, time of day, shape of the container

• Temperature, pH level, type of milk used, presence of other microorganisms, and incubation time.