Welcome to Food Processing, HACCP, and Labelling!

Ever wondered why a can of soup stays fresh for years, or how astronauts eat strawberries in space? This chapter explores the "behind-the-scenes" of the food industry. We will look at how technology keeps our food safe (Processing), how companies prevent mistakes (HACCP), and what those tiny words on the back of your snack bag actually mean (Labelling).

Don't worry if it seems like a lot of technical terms at first. Think of this as the "Safety and Quality" manual for everything you eat!

1. Advanced Food Processing Technology

In the elective module, we focus specifically on two high-tech methods used to keep food fresh for a long time: Canning and Freeze-drying.

A. Canning

Canning is a method of preserving food by heating it in airtight containers. It uses the principle of sterilisation.

  • How it works: The food is sealed in a container and heated to a high temperature (usually above \(100^\circ C\)). This heat kills micro-organisms (like bacteria) and destroys enzymes that cause spoilage.
  • The Seal: The airtight (hermetic) seal prevents any new bacteria from getting inside.
  • Key Steps: Cleaning \(\rightarrow\) Blanching (briefly boiling) \(\rightarrow\) Filling \(\rightarrow\) Exhausting (removing air) \(\rightarrow\) Sealing \(\rightarrow\) Heat Processing \(\rightarrow\) Cooling.

B. Freeze-drying

This is one of the best ways to preserve food because it keeps the food's original shape, colour, and nutrients.

  • The Science: It works by a process called sublimation. This is where ice turns directly into water vapour without becoming liquid first.
  • How it works:
    1. The food is quickly frozen.
    2. It is placed in a vacuum.
    3. A small amount of heat is added, causing the frozen water to "vaporise" away.
  • Advantages: The food is very light (great for transport), has a long shelf life, and tastes almost exactly like the original when water is added back.

Quick Review: Canning uses heat to kill bacteria. Freeze-drying removes water through sublimation in a vacuum.

2. HACCP: The Food Safety Watchdog

HACCP stands for Hazard Analysis and Critical Control Point. It is an international system used to prevent food safety problems before they happen.

Instead of just checking the final product for bacteria, HACCP looks at every single step of production—from the farm to the table—to find where things could go wrong.

The 7 Principles of HACCP

  1. Conduct Hazard Analysis: Identify any biological (e.g., Salmonellae), chemical (e.g., pesticides), or physical (e.g., glass) hazards.
  2. Determine Critical Control Points (CCPs): Find the steps where you must control the hazard (e.g., the cooking step).
  3. Establish Critical Limits: Set clear rules for the CCPs (e.g., "The chicken must reach a temperature of \(75^\circ C\)").
  4. Establish Monitoring Procedures: Regularly check that the limits are met (e.g., using a thermometer to check the chicken).
  5. Establish Corrective Actions: Decide what to do if something goes wrong (e.g., "If the chicken is only \(60^\circ C\), cook it longer").
  6. Establish Verification Procedures: Double-check that the whole system is working (e.g., testing the equipment).
  7. Establish Record-keeping: Keep a logbook of all measurements and actions.

Analogy: Imagine you are crossing a busy road. Hazard analysis is noticing the cars. The Critical Control Point is the traffic light. The Critical Limit is the red light. Monitoring is looking at the light. Corrective action is stopping if it's red!

3. Packaging Materials

Packaging isn't just a wrapper; it's a protective shield for food. Different foods need different materials:

  • Metal (Cans): Strong, provides a total barrier against light and air, but can be heavy.
  • Glass: Transparent (you can see the food) and chemically inert (doesn't react with food), but breaks easily and is heavy.
  • Plastics: Versatile, lightweight, and cheap. They can be made into films, bottles, or trays.
  • Paper and Cardboard: Lightweight and easy to print on, but not waterproof unless coated with plastic or wax.

Environmental Note: As consumers, we must consider the sustainability of packaging. Many companies are moving toward recyclable or biodegradable materials to reduce waste and protect the environment.

In Hong Kong, the law requires food manufacturers to provide specific information on labels. This helps consumers make safe and healthy choices.

What MUST be on a label?

  • Name of the Food: It shouldn't be misleading.
  • List of Ingredients: Listed in descending order of weight (the heaviest ingredient comes first).
  • Indication of "Best Before" or "Use By" Date:
    • "Use By" is for highly perishable foods (safety risk).
    • "Best Before" is about food quality.
  • Statement of Special Storage Conditions: (e.g., "Keep refrigerated").
  • Name and Address of Manufacturer/Packer: To know who is responsible for the food.
  • Count, Weight, or Volume: How much food is inside.

Nutrition Labelling (The "1+7" Rule)

In Hong Kong, most prepackaged foods must show the Energy value plus seven core nutrients:
1. Protein
2. Carbohydrates
3. Total Fat
4. Saturated Fat
5. Trans Fat
6. Sodium
7. Sugars

Common Mistake: Don't confuse "Saturated Fat" with "Total Fat." Saturated fat is just one part of the total fat content!

Key Takeaways for the Exam

  • Canning uses high heat (sterilisation) to preserve food in sealed containers.
  • Freeze-drying uses sublimation in a vacuum to remove water while keeping food quality high.
  • HACCP is a 7-step preventive system to ensure food safety. Memorise the order of the principles!
  • Food labels must be accurate and include ingredients in descending weight order, dates, and the "1+7" nutrition info.
  • Always consider the environmental impact of the packaging materials used in food production.

Note: For more details on the chemicals added to food during processing, check out the chapter on "Food additives and the International Numbering System."