Essential Nutrition and Food Safety Principles

Posted on Oct 25, 2025 in Medicine & Health

The Eatwell Guide: Achieving a Balanced Diet

A balanced diet is essential because it:

• Provides energy for survival.
• Supports the growth and repair of body tissue.
• Maintains essential bodily functions.
• Prevents hunger.
• Promotes overall health and well-being.

The Five Food Groups

• Fruit and vegetables.
• Starchy carbohydrates (Potatoes, bread, rice, pasta).
• Proteins (Beans, pulses, fish, eggs, meat).
• Dairy and alternatives.
• Fats and oils.

The Eatwell Guide applies to everyone regardless of weight, dietary restrictions, or ethnic origin. Note: It does not apply to children under 2 years because they have different nutritional needs.

Fruit and Vegetables

• Fruit and vegetables should make up approximately ⅓ of the food we eat each day.
• Eat at least 5 portions of fruit and vegetables daily.
• Choose from fresh, frozen, canned, dried, or juiced options.

Potatoes, Bread, Rice, Pasta, and Other Starchy Carbohydrates

• Starchy food should make up approximately ⅓ of the food we eat per day.
• Choose higher-fibre, whole grain options. These contain more fibre and other nutrients, digest slowly, and help us feel full for longer, supporting increased fibre intake.

Beans, Pulses, Fish, Eggs, Meat, and Other Proteins

These are important sources of protein, vitamins, and minerals.

• Beans, peas, and lentils are good alternatives to meat, often being low in fat and high in fibre, protein, vitamins, and minerals.
• Aim for 2 portions of fish a week, including at least one portion of oily fish.
• Some types of meat are high in saturated fat. The type of cut and the way you cook meat make a difference.
• Limit red and processed meat consumption to no more than 70g per day.

Dairy and Alternatives

• Consume milk and dairy foods such as cheese, yogurt, and fromage frais.
• They are good sources of protein, vitamins, and calcium, which helps keep our bones strong.
• Some dairy foods are high in fat and saturated fat. Choose lower-fat options where possible.

Oils and Spreads

• A small amount of fat in your diet is essential.
• Unsaturated fats (typically from plant sources) are considered healthy fats.
• Unsaturated fats can help reduce cholesterol in the blood.
• All types of fat are high in energy, so consumption should be limited in the diet.

Hydration

• Drink 6–8 glasses of fluid every day.
• Suitable fluids include water, lower-fat milk, sugar-free drinks, tea, and coffee.
• Limit consumption of fruit juices and smoothies (due to free sugars) to a combined total of 150ml per day.
• Sugary drinks contribute to excess sugar intake amongst children and adults.
• Choose ‘no added sugar’ options to reduce overall sugar intake.

Foods High in Fat, Salt, and Sugars (HFSS)

Examples include chocolate, cakes, biscuits, full-sugar soft drinks, butter, and ice cream.

• These foods are not needed in the diet and should only be consumed in small amounts.
• Limit their consumption as they contain lots of energy (calories).
• Avoid foods that are excessively high in fat, salt, and sugar.
• When choosing these items, opt for lower fat and lower sugar alternatives.

Food Safety and Microorganisms

Bacteria

• Bacteria are single-celled microorganisms.
• They are present in the air, soil, and on animals and humans.
• Some foods naturally contain microorganisms.
• Bacteria can be transferred to food through poor hygienic practices.

Function of Bacteria

Harmless bacteria are used in food manufacture (e.g., making cheese and yogurt).

Spoilage and Pathogens

Spoilage bacteria are often undetected because the food may look, taste, and smell normal. Food poisoning bacteria are known as pathogenic bacteria and are very harmful.

Conditions Needed for Bacterial Growth

Bacteria are active in high-risk foods when the following conditions are met:

• Warmth: Active in the temperature range of 5°C to 63°C (the Danger Zone). The optimal temperature for growth is around 37°C (human body temperature).
• Moisture: Required for activity.
• Food: Especially high-protein foods.
• Time: They reproduce rapidly by dividing (binary fission).
• pH: They grow rapidly in neutral pH conditions.

Note: Most bacteria cannot survive temperatures of 70°C or above. Some are able to form spores to survive adverse conditions.

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Moulds

Function of Moulds

Harmless moulds are used in food manufacture (e.g., blue-veined cheese).

Spoilage by Moulds

Moulds are visible to the eye, growing on the surface of food. They can be black, white, or blue. Moulds reproduce by producing spores.

Conditions Needed for Mould Growth

• Grows quickly in moist conditions.
• Optimal temperatures are 20°C–30°C.
• Mould grows slowly in dry, cold conditions.
• Grows on foods that may be dry, moist, acid, alkaline, or have high salt or sugar concentrations.

Yeast

Function: Through the process of fermentation, yeasts are used to make breads and alcohol. Yeasts are also responsible for food spoilage in high-sugar foods such as fruit, jam, and fruit yogurt.

Conditions Needed for Yeast Growth

• Active in warm, moist conditions with food for growth and reproduction.
• Oxygen is not always needed for growth (anaerobic growth).

Helpful Properties of Microorganisms

• Not all microorganisms are harmful.
• Probiotic foods contain live bacteria (often called ‘friendly bacteria’).
• Enzymes produced by microorganisms are used in manufacturing processes, such as bread making, brewing, and the ripening stage of cheese.

Food Spoilage and Preservation

• Food that is not preserved deteriorates and becomes unfit to eat.
• Deterioration is caused by microorganisms and enzymes.
• Food preservation increases the shelf life of products.

Food Hygiene Practices

Buying and Storing Food Safely

• Food is in danger of becoming infected at each stage of its production.
• Poor hygiene can lead to contamination and food poisoning. Always buy food from a reputable shop.
• Food must be stored correctly:
  • Refrigerators: Should be kept between 0°C and 5°C. This slows down the growth of food poisoning bacteria.
  • Freezers and Freezing: Should be kept at -18°C. Food poisoning bacteria are dormant in a freezer.

Essential Rules for Food Hygiene

1. Wash your hands thoroughly before handling food.
2. Keep raw and cooked foods separated.
3. Use different and clean equipment for raw and cooked foods.
4. Wear clean protective clothing, cover cuts, and never cough or sneeze over food.
5. Cover and cool all cooked food rapidly.
6. Store food below 5°C.
7. Do not place hot foods directly into the refrigerator.
8. Keep pets away from food preparation areas.
9. Keep flies out of the kitchen.

How Bacteria Get Into Food (Contamination)

Pathogenic bacteria cause food poisoning. Contamination occurs due to:

• Poor hygiene during production and serving of food.
• Cross-contamination between raw foods and cooked foods.
• Improper storage of high-risk foods.

Poor Preparation and Cooking Routines

• Not thawing foods properly.
• Preparing food too far in advance.
• Undercooking high-risk foods.
• Not allowing foods to cool rapidly.
• Not reheating foods to the correct temperature for a long enough time (and not checking temperature accurately with a probe).
• Leaving food on display at room temperature, or holding hot foods below 63°C.

Preventing Cross-Contamination

Microorganisms can transfer from raw to cooked food, causing infection. To prevent cross-contamination:

• Avoid raw and cooked food touching each other.
• Avoid blood and juices from raw food dripping onto cooked food.
• Avoid bacteria being transferred during handling or preparation (e.g., using the same chopping board).

Increase in Food Poisoning Cases

Reasons for the increase in reported cases of food poisoning include:

• Increased use of microwaves (food is often not cooked to correct temperatures).
• Increased use of cook-chill methods (especially for high-risk food).
• Foods not stored at the correct temperatures.
• Food not prepared correctly.
• Poor personal hygiene.

High-Risk and Low-Risk Foods

High-Risk Foods

These foods typically have high protein and moisture content, making them ideal for bacterial growth:

• Raw fish and shellfish.
• Dairy products.
• Cooked meat and poultry.
• Gravies, sauces, stocks, soups, and stews.
• Egg products.
• Cooked rice.
• Protein-based baby foods.

Low-Risk Foods

• High acid content foods (e.g., pickles).
• High sugar content foods (e.g., jam).
• Sugar-based confectionery.
• Unprocessed raw vegetables.
• Edible oils and fats.

Common Food Poisoning Bacteria and Sources

How Bacteria Grow (Binary Fission)

Bacteria multiply or reproduce by binary fission. They require the following conditions:

• Warmth: Optimal range is 37°C to 63°C. Temperatures of 72°C or higher kill most bacteria.
• Moisture: Required for growth (dried foods have a longer shelf life).
• Food: Especially foods high in protein and moisture.
• Time: They multiply quickly.

Factors Influencing Food Choice

The Importance of a Healthy Balanced Diet

Eating the right balanced diet provides the energy and nutrients needed to stay healthy. A healthy balanced diet combined with regular physical activity helps people maintain a healthy weight and reduces the chance of developing illness.

Key Factors Affecting Diet Selection

A balanced diet depends on many factors, including:

• Individual energy and nutrient needs.
• Health concerns.
• Portion size.
• Cultural or religious practices.
• Cost.
• Social and economic considerations.
• Food availability.
• Food preferences.
• Environmental and ethical considerations.
• Advertising and other point-of-sale information.

Individual Energy and Nutrient Needs

The amount of energy, carbohydrate, fat, protein, vitamins, and minerals needed varies based on age, gender, and activity levels. For example, athletes have much higher energy requirements due to their high level of physical activity.

Health Concerns

Diets that exclude many foods due to health concerns or medical reasons (e.g., allergies, intolerances) need to be planned carefully to ensure nutritional adequacy.

Portion Size

• A balanced diet involves getting the right amount of food and drinks.
• Portion sizes are important when making food choices.
• Follow a healthy, balanced, and varied diet, using guidelines like the Eatwell Guide.

Cultural or Religious Practices

Ethical and religious practices limit the range of food that people eat. For example, a vegan will not consume any animal products and must choose alternative sources to meet their protein and nutrient needs.

Cost

The cost of food significantly influences people’s food choices. If money is limited, people will buy basic items, and luxury items may be reserved for special occasions. Food prepared at home is generally cheaper.

Food Availability

Most food is grown in a particular season of the year (e.g., strawberries in summer). These are called seasonal foods. Buying food when it is in season is often cheaper. Technology has allowed food to be available all year round. Frozen vegetables are great alternatives to fresh produce.

Food Preferences

Not everyone likes the same food. Taste, texture, or appearance can affect preferences. People should choose a balanced diet while selecting foods they enjoy.

Environmental and Ethical Considerations

The impact of food production on the environment is a high social concern for some people. Considerations when buying food might include:

• Fair Trade: Ensuring producers receive fair prices.
• Buying Local Food: Supports local businesses and farmers.
• Genetically Modified Food (GM): Food produced from organisms whose genetic material has been altered in a way that does not occur naturally.

Advertising and Point-of-Sale Information

• Advertising encourages people to choose certain foods via television, the internet, radio, posters, magazines, and newspapers.
• Point-of-sale information provides data to consumers to help them make healthier choices.

Other Sources of Information

Sources to help people when making food choices include:

• Department of Health
• NHS Choices
• British Nutrition Foundation
• Supermarkets, food manufacturers, charities, etc.
• The media (internet)

Important: Look for the information standards logo.

Food Labeling Requirements

Information required on the labels of pre-packed food and drink products:

• Name of the product.
• List of ingredients (including additives).
• Weight or volume.
• Date mark (e.g., ‘Use By’ or ‘Best Before’).
• Storage and preparation conditions.
• Name and address of the manufacturer, packer, or seller.
• Country of origin and place of provenance.
• Nutrition information.

Cooking Fundamentals and Ingredients

Choux Pastry

Eggs

Terminology

• Denature: Altering the physical properties of protein (e.g., by heat or acid).
• Coagulation: The setting or thickening of protein (e.g., when eggs are heated).
• Coagulate: To set or thicken.
• Setting: The process of coagulation.

The Reference Nutrient Intake (RNI) for protein is approximately 0.75g per kg of body weight. One egg provides about 6g of protein.

The Lion Mark

• The Lion mark shows that an egg has been produced to the highest food safety standards.

Inside of an Egg

Nutritional Value of Eggs

• Micronutrients include Vitamin A, important for normal vision, the immune system, and reproduction, and helping organs like the heart and lungs function.
• Vitamin B12 is needed for iron absorption.
• Eggs are a source of Iron.
• Eggs do not contain carbohydrates or Vitamin C.

Functions of Eggs in Cooking

• Trap air (aeration).
• Bind ingredients together.
• Coat products to protect them when cooking (e.g., breading).
• Thicken products (e.g., custards).
• Act as an emulsifier (preventing oil and water from separating).
• Glaze products.
• Enrich products.
• Garnish products.

Milk and Milk Processing

Homogenised Milk

Primary and Secondary Processing

• Primary Processing: Changing a basic food to preserve it or prepare it for sale or cooking (e.g., milling wheat into flour).
• Secondary Processing: Using a primary processed food to make another product (e.g., using flour to make bread).

Pasteurised Milk

Raw milk that has been heated to a specific temperature for a specific time to kill pathogens (e.g., 71.7°C for 15 seconds).

• Pathogens are microorganisms, such as bacteria, that cause illness (food poisoning).
• Vitamins A and D are often added to milk, but no other additives are typically included.

Sterilised Milk

• Sterilised milk is heated between 120°C and 135°C.
• No preservatives are involved.
• The nutritional value is similar to fresh milk.
• Sterilised milk has a slightly sweeter taste than fresh milk due to the heat treatment.

UHT Milk (Ultra Heat Treatment)

• UHT milk is ultra-pasteurized milk packaged in sterilised containers.
• This special pasteurisation and packaging process gives it a long shelf life.
• The process kills bacteria that may be harmful or cause milk to spoil.
• UHT milk can remain unrefrigerated for about 3 months until the container is opened, after which it must be refrigerated.

Vitamins and Minerals

Types of Vitamins

Vitamins are micronutrients, divided into two groups:

• Fat-soluble vitamins (A, D, E, K).
• Water-soluble vitamins (B group and C).

Importance of Vitamins

• Maintain overall health.
• Regulate the repair of body cells.
• Help release energy from food.
• Prevent deficiency diseases.
• Support the immune system.

Antioxidants

Antioxidants help protect our body against ‘free radicals’, which are produced when we break down food, or are introduced through external factors like tobacco smoke and radiation.

B Vitamins

Thiamin (Vitamin B1)

Function:

• Supports growth.
• Helps maintain a normal nervous system.
• Helps release energy from carbohydrates.

Deficiencies: Fatigue, poor memory, loss of appetite, and sleep disturbances.

Riboflavin (Vitamin B2)

• Helps the body absorb iron.

Deficiency: Can cause poor growth rate and skin/eye problems.

Niacin (Vitamin B3)

Found in: Fish, chicken/beef, and turkey.

Deficiency: Can cause rough, sore skin, weakness, and depression.

Folate / Folic Acid (B Vitamin)

Function:

• Helps the body develop.
• Essential for the formation of body cells.

Deficiency: Tiredness, anaemia, forgetfulness, depression, and irritability.

Vitamin C (Ascorbic Acid)

Function:

• Aids the formation of connective tissue.
• Helps blood and blood vessel formation.
• Assists in iron absorption.
• Promotes healing.
• Aids calcium absorption.

Note: The body does not store Vitamin C, so a regular intake is required.

Vegetables and Cooking Methods

Vegetables

Vegetables provide a range of minerals and vitamins (micronutrients) and are high in fibre.

Ways to Cook Vegetables

• Boiled
• Roasted in the oven
• Casserole
• Stir-fried
• Fried
• Soups
• Salads (raw)

Storing Vegetables

• Look for fresh, crunchy vegetables with bright colour.
• Store in a cool, dry place.
• Potatoes should be stored covered.
• Leave vegetables in their original bag if it has been treated with CO2 to maintain freshness.

Types of Vegetables

• Root Vegetables: Carrots, parsnips.
• Tubers: Potatoes, sweet potatoes (attached to the plant by tubers).
• Bulbs: Onion, garlic, turnip, celeriac (sits on top of the soil with roots beneath).
• Stems: Celery, asparagus, fennel (we eat the stem).
• Leaves: Cavolo nero, curly kale, sprouts, lettuce.
• Flower Heads: Broccoli, cauliflower.
• Fungi: Mushrooms.

When vegetables are cooked, they often become less bitter.

Pasta Preparation

Basic pasta ingredients:

1. Flour: Pasta flour (e.g., durum wheat semolina).
2. Egg: Provides the necessary liquid and structure.
3. Olive Oil: Helps make the pasta glossy and pliable.

• When cooking pasta, it becomes soft and its weight increases approximately three times compared to raw pasta.
• Using a pasta machine involves pushing the pasta dough through multiple times, reducing the width and folding it.
• Flavoured pasta (e.g., green pesto pasta) often uses ingredients like spinach for colour and flavour.

Cooking Meat

Meat provides nutrients such as protein, Vitamin B3, B complex vitamins, magnesium, zinc, and potassium.

Why Cook Meat?

• Removes harmful bacteria.
• Makes meat easier to swallow, chew, and digest.
• Develops flavour.

Note: Some meats, like steak tartare and carpaccio, are eaten raw, but this carries a higher risk.

Buying Meat

When buying meat, ensure it:

• Smells and looks fresh.
• Is stored in good conditions.
• Is purchased from a clean shop.
• Check the expiry date.

Storage of Meat

• Store below 5°C, as bacteria cannot reproduce as fast at this temperature.
• Keep meat in a well-closed package (often containing CO2 to preserve it). Keep it closed to prevent drying out.
• After freezing and thawing, use meat quickly.

Chicken

Advantages of Using Chicken

• Low cost of raising chicken.
• Low fat content.
• High in protein.

Raw Chicken Safety

• Bacteria associated with raw chicken include Salmonella and Campylobacter.
• Chicken is a high-risk food and should be stored under 5°C (the danger zone for bacterial multiplication is 5°C–63°C).
• Use a red chopping board for raw poultry to prevent cross-contamination.

Prices of Chicken Parts (Per kg, illustrative)

• Whole chicken: £4.50
• Thigh fillet: £5.76
• Chicken thighs: £3.00
• Chicken drumsticks: £2.50
• Chicken legs: £3.50
• Chicken breast: £8.33
• Chicken wings: £2.19

Purpose of Marinades

• Tenderise the meat.
• Add flavour to the food.
• Add moisture.
• Make the meat nicer and more attractive.

Victoria Sponge: Creaming Method

• Air is used as a natural raising agent.
• Eggs help to set the air in place (coagulation).
• Baking powder is a chemical raising agent (containing baking soda/sodium bicarbonate). When heated, it gives off carbon dioxide (CO2) gas.
• Preheating the oven is essential to ensure the mixture rises correctly.

How Cakes Cook

• Hot air rises when the cake is placed in the oven, and the eggs set (coagulate) at approximately 70°C, giving the cake structure.

Ingredients and Functions (All-in-One Method implied by original text)

• Self-raising flour: Gives structure.
• Soft margarine: Easier to whisk / makes the cake soft.
• Eggs: Set the mixture in place.
• Caster sugar: Makes the mixture sweet (for taste).
• Baking powder: Makes the cake big and fluffy.

Qualities of good cupcakes include being golden brown, fluffy, and light.