Podcast
Questions and Answers
Which of the following statements accurately describes the role of Lactobacillus bacteria in fermentation?
Which of the following statements accurately describes the role of Lactobacillus bacteria in fermentation?
- Lactobacillus bacteria convert lactic acid into sugars.
- Lactobacillus bacteria convert sugars into lactic acid. (correct)
- Lactobacillus bacteria increase the protein content of foods.
- Lactobacillus bacteria produce ethanol as the main byproduct.
What is a consequence of milk pH falling below 4.6?
What is a consequence of milk pH falling below 4.6?
- The milk forms a cream layer.
- Casein proteins begin to precipitate. (correct)
- The whey becomes coagulated.
- The lactose content increases significantly.
Which of the following best describes bongkrekic acid?
Which of the following best describes bongkrekic acid?
- A non-toxic byproduct of Lactobacillus fermentation.
- A toxin produced by Burkholderia gladioli. (correct)
- A natural preservative generated during fermentation.
- A common ingredient in Southeast Asian dairy products.
How does the fermentation process enhance the nutritional profile of food?
How does the fermentation process enhance the nutritional profile of food?
What is the primary protein found in milk, and what percentage does it account for?
What is the primary protein found in milk, and what percentage does it account for?
Which condition is most likely to cause an increase in the pH level of cow's milk?
Which condition is most likely to cause an increase in the pH level of cow's milk?
What is the main function of lactic acid in fermented foods?
What is the main function of lactic acid in fermented foods?
Which of the following statements about milk composition is correct?
Which of the following statements about milk composition is correct?
What is the primary purpose of milk pasteurization?
What is the primary purpose of milk pasteurization?
Which of the following describes the limitations of typical food industry heat treatments on endospores?
Which of the following describes the limitations of typical food industry heat treatments on endospores?
Which vitamin is NOT naturally abundant in cow's milk?
Which vitamin is NOT naturally abundant in cow's milk?
What is the temperature and time requirement for the High Temperature-Short Time (HTST) pasteurization method?
What is the temperature and time requirement for the High Temperature-Short Time (HTST) pasteurization method?
Which component of an endospore contributes to its chemical and enzymatic resistance?
Which component of an endospore contributes to its chemical and enzymatic resistance?
In low temperature-long time (LTLT) pasteurization, what is the temperature used?
In low temperature-long time (LTLT) pasteurization, what is the temperature used?
What is a consequence of the high-temperature pasteurization process on milk?
What is a consequence of the high-temperature pasteurization process on milk?
What is the typical leucocyte count in non-mastitic milk?
What is the typical leucocyte count in non-mastitic milk?
What type of organisms are primarily targeted by the UHT treatment in milk?
What type of organisms are primarily targeted by the UHT treatment in milk?
Which temperature range is essential for effective UHT treatment of milk?
Which temperature range is essential for effective UHT treatment of milk?
What causes spoilage in UHT-treated milk?
What causes spoilage in UHT-treated milk?
What distinguishes prebiotics from probiotics?
What distinguishes prebiotics from probiotics?
Which of the following pathogens is primarily associated with milk?
Which of the following pathogens is primarily associated with milk?
What is a commonly used probiotic organism in yogurt production?
What is a commonly used probiotic organism in yogurt production?
What is the typical shelf life of UHT-treated milk when aseptically packaged?
What is the typical shelf life of UHT-treated milk when aseptically packaged?
Which of the following statements regarding milk microbiota is accurate?
Which of the following statements regarding milk microbiota is accurate?
What role do bifidobacteria and anaerobic lactobacilli play in the colon?
What role do bifidobacteria and anaerobic lactobacilli play in the colon?
Which of the following is a characteristic of lactose intolerance?
Which of the following is a characteristic of lactose intolerance?
Why are lactic starters crucial in the dairy industry?
Why are lactic starters crucial in the dairy industry?
Which lactic starter is included when flavor compounds such as diacetyl are desired?
Which lactic starter is included when flavor compounds such as diacetyl are desired?
In the production of cultured sour cream, what is the initial step taken?
In the production of cultured sour cream, what is the initial step taken?
What is the pH range typically produced by the rod bacteria during fermentation?
What is the pH range typically produced by the rod bacteria during fermentation?
What happens to the milk that remains after butter is churned?
What happens to the milk that remains after butter is churned?
Which of the following statements about coccus and rod bacteria during fermentation is accurate?
Which of the following statements about coccus and rod bacteria during fermentation is accurate?
Study Notes
Fermentation
- Fermentation enhances shelf stability and provides distinct aroma and flavors from fermenting organisms.
- Lactobacillus bacteria convert sugars into lactic acid, which acts as a natural preservative against harmful bacteria while preserving nutrients.
- Bongkrekic acid, a toxin produced by Burkholderia gladioli, has been linked to cases of poisoning from fermented coconut and corn products.
- Fermentation encompasses a range of chemical changes and is integral to food processing.
Dairy Products
- Milk is a universal human food source derived from various mammals.
- Milk contains 3.5% protein and 14.9% carbohydrates, primarily consisting of casein (80-85% of protein).
- Milk pH typically ranges around 6.6 but can rise to 6.8 in infected cows (mastitis), which is caused by bacteria like Streptococcus and Staphylococcus species.
- Fresh milk is an ideal medium for lactic acid bacteria, which thrive in its nutrient composition.
Processing: Pasteurization
- Pasteurization aims to eliminate disease-causing microorganisms; however, it does not kill endospores from certain bacteria (e.g., Clostridium).
- Common pasteurization methods include:
- Low temperature-long time (LTLT): 145°F (63°C) for 30 minutes.
- High temperature-short time (HTST): 161°F (72°C) for 15 seconds.
- Ultra-high temperature (UHT): 275-284°F (135-140°C) for a few seconds, yielding commercially sterile milk.
Microbiota and Pathogens
- Fresh milk is generally not free from microorganisms, with potential pathogens including Brucellosis, Anthrax, and Salmonella.
- Milk spoilage is primarily caused by specific bacteria that can metabolize lactose, unlike other sugars.
Probiotics and Prebiotics
- Probiotics consist of live beneficial organisms, commonly found in yogurt, which utilizes Streptococcus thermophilus and Lactobacillus bulgaricus.
- Prebiotics are non-digestible substrates that enhance the growth of beneficial bacteria in the colon, such as oligosaccharides and inulin.
Lactose Intolerance
- Lactose intolerance is common in adults, where insufficient lactase leads to digestive symptoms upon milk consumption.
Starter Cultures and Fermented Products
- Lactic starters, essential for cheese making and other dairy products, include various Lactobacillus strains.
- Butter is made by churning inoculated cream; buttermilk remains after butter is produced.
- Cultured sour cream is made by fermenting pasteurized cream, while yogurt fermentation involves both cocci and rods for lactic acid production, affecting the final product's acidity.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz explores the processes of fermentation in milk and its impact on dairy products. Gain insights into the role of bacteria like Lactobacillus in enhancing flavor, aroma, and nutritional content of both fermented and non-fermented dairy. Understand the significance of fermentation in food preservation and digestibility.
