BIOS 242 Week 4 Pasteurization and Sterilization

BIOS 242 Week 4 Pasteurization and Sterilization

Student Name

Chamberlain University

BIOS-242 Fundamentals of Microbiology

Prof. Name:

Date

Lab 4: Pasteurization and Sterilization

Learning Outcomes

• Explain the concept of food spoilage and shelf life.
• Explain the principles of pasteurization and sterilization.
• Analyze the parameters of High-Temperature-Time-Treatment (HTST) pasteurization.
• Perform canning as a method of sterilization.
• Identify how plastic and metal can be used as materials for packaging.

Introduction

In this virtual simulation lab on pasteurization and sterilization, you will assist Adam, an organic farmer, with increasing the shelf life of his peach juice. Together with Marie, a food scientist, you will explore the basics of food spoilage and shelf life by conducting spoilage detection experiments. Next, you will investigate two heat treatments—pasteurization and sterilization—that can prevent spoilage in the peach juice. The final task is to apply this knowledge to determine the most suitable packaging and heat treatment for Adam’s peach juice. The ultimate goal is to eliminate spoilage and extend the shelf life of the juice.

Questions

1. Purpose: Why is food safety important?

Food safety is crucial to prevent the consumption of food that is contaminated with harmful bacteria or spoiled. Eating spoiled or bacteria-infested food can lead to serious illnesses, including food poisoning, which can sometimes be fatal. Food safety measures protect public health by ensuring that food is safe to consume.

2. What practices would you recommend to keep food safe at home?

• Always check expiration dates before consuming any food.
• Keep perishable items refrigerated.
• Do not eat food that smells bad.
• Reheat food to a high temperature before consuming.
• Avoid purchasing food that is close to its expiration date.
• Always keep food containers covered and closed.
• Clean the microwave before reheating food.

3. What would you recommend for the storage of milk at home?

• Always check the expiration date before using milk.
• Inspect the milk for any signs of spoilage when pouring it into a glass.
• Smell the milk to check for a sour odor, indicating spoilage.

4. What is the difference between pasteurization and sterilization?

Pasteurization is a heat treatment process that reduces microbial growth and food spoilage. It involves heating food to a specific temperature to prolong shelf life. Sterilization, on the other hand, involves using heat above 100°C to eliminate all spoilage microorganisms, effectively making the food free from harmful microbes and extending its shelf life significantly.

Reflection

This simulation taught me that the three main types of microorganisms responsible for food spoilage are bacteria, yeast, and mold. I also learned the steps involved in pasteurization and the critical temperatures required to maintain the shelf life of food. Measuring the pH of peach juice was particularly interesting, as I discovered that canned juice has a lower pH compared to bottled or fresh juice. Additionally, I learned that bacterial contamination is measured in CFU/ml, which I found memorable. I enjoyed testing the pH of the juice and forming a hypothesis. The machine used to count the number of bacteria on an agar plate was fascinating, and I appreciated using the pipette to collect samples. The only downside was that the lab was virtual—performing these experiments in a real lab setting would have been far more satisfying.

Grading Rubric

BIOS 242 Week 4 Pasteurization and Sterilization

References

• Food Safety and Inspection Service. (2020). Basics of food safety. U.S. Department of Agriculture.
• Mullan, L. M., & Bozeman, S. (2015). Food safety and quality systems in developing countries: Perspectives from the United States and Europe. Springer.