Active learning ideas
Heat treatment is one of the most common ways to preserve food commercially. This topic covers the differences between pasteurisation, Ultra-High Temperature (UHT) processing, and canning. Students analyze how these methods use heat to destroy pathogens and enzymes, while also considering the trade-offs in terms of nutritional value and sensory properties.
Activity 01
Students conduct a blind taste test of pasteurised and UHT milk. They discuss the differences in flavor and color, then work in pairs to explain how the different heat intensities caused these sensory changes.
How does pasteurisation differ from UHT?
Activity 02
Groups are given jumbled steps of the canning process (blanching, filling, exhausting, sealing, processing, cooling). They must arrange them in order and explain the scientific purpose of each step to the class.
What are the steps involved in the canning process?
Activity 03
Students debate the pros and cons of canned vs. fresh vegetables, focusing on heat-sensitive vitamins like Vitamin C. They must use evidence to argue whether the convenience and safety of canning outweigh the nutrient loss.
How does heat treatment affect heat-sensitive vitamins?
A few notes on teaching this unit
Watch Out for These Misconceptions
UHT milk has preservatives added to make it last longer.
The long shelf life is due to the high-temperature treatment and aseptic packaging, not chemicals. A 'process flow' diagram activity helps students see that heat alone is the preserving agent.
Canned food lasts forever.
While very stable, canned food has a 'best before' date and can spoil if the seal is damaged. A 'can inspection' activity helps students identify signs of spoilage like bulging or rusting.
Methods used in this brief
Reasons for Food Preservation
Understand the causes of food spoilage and the principles behind food preservation. Explore how preservation extends shelf life and ensures food safety.
8 methodologies
Cold Preservation and Dehydration
Examine the use of chilling, freezing, and dehydration in preserving food. Analyze how these methods inhibit microbial growth and enzymatic activity.
8 methodologies