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MATSEC AM Home Economics and Human Ecology study materials
MATSEC AM Home Economics and Human Ecology study resources

MATSEC AM Home Economics and Human Ecology practice questions

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Question 1Food, Nutrition and Health

Which nutrient is the primary structural component of antibodies and enzymes in the human body?

  1. Vitamin C
  2. Dietary fibre
  3. Protein Correct answer.
  4. Sodium chloride

Explanation

Antibodies and enzymes are both built from amino acid chains, so protein supplies the raw material for their structure. Dietary fibre, vitamin C and sodium chloride serve other roles and cannot form these molecules.

Question 2Food, Nutrition and Health

A student reads a food label stating that 100 g of a breakfast cereal provides 8 g of dietary fibre. What does this figure indicate about the cereal?

  1. It supplies a portion of the indigestible carbohydrate needed for healthy bowel function Correct answer.
  2. It contains 8 g of protein from wholegrain sources
  3. It provides 8 g of available energy-yielding starch
  4. It is fortified with eight grams of added sugar

Explanation

Dietary fibre is the indigestible carbohydrate component of plant foods, and the label value quantifies how much of it the cereal delivers per 100 g. It is not energy-yielding starch, protein or sugar.

Question 3Food, Nutrition and Health

Which mineral is essential for the formation of haemoglobin and is best absorbed from red meat sources?

  1. Iron Correct answer.
  2. Iodine
  3. Calcium
  4. Potassium

Explanation

Haemoglobin requires iron at the centre of its haem group to bind oxygen. Haem iron from red meat is absorbed more efficiently than non-haem iron from plant foods.

Question 4Food, Nutrition and Health

Which vitamin deficiency classically causes scurvy, with bleeding gums and poor wound healing?

  1. Vitamin D
  2. Vitamin C Correct answer.
  3. Vitamin B12
  4. Vitamin A

Explanation

Vitamin C is required for collagen synthesis, so deficiency weakens connective tissue and produces bleeding gums and delayed healing. The other vitamins listed have different deficiency syndromes.

Question 5Food, Nutrition and Health

Which food-handling practice best reduces the risk of cross-contamination in a domestic kitchen?

  1. Using separate colour-coded boards for raw meat and ready-to-eat foods Correct answer.
  2. Thawing frozen chicken on the kitchen counter overnight
  3. Using the same board for raw chicken and salad vegetables after a quick rinse
  4. Storing raw meat above ready-to-eat foods in the refrigerator

Explanation

Separate boards prevent bacteria such as Campylobacter and Salmonella from raw meat transferring onto foods eaten without further cooking. Rinsing or shared surfaces do not reliably remove contamination.

Question 6Food, Nutrition and Health

Which macronutrient provides 9 kcal (approximately 37 kJ) per gram?

  1. Carbohydrate
  2. Protein
  3. Alcohol
  4. Fat Correct answer.

Explanation

Fat is the most energy-dense macronutrient, supplying about 9 kcal per gram. Carbohydrate and protein supply about 4 kcal per gram, and alcohol about 7 kcal per gram.

Question 7Food, Nutrition and Health

Which dietary change is most appropriate for a person advised to follow a low-sodium diet for hypertension?

  1. Drinking more flavoured mineral water
  2. Replacing processed meats and stock cubes with fresh meat and herbs Correct answer.
  3. Adding soy sauce to every cooked dish
  4. Increasing intake of salted crackers and cheese

Explanation

Most dietary sodium comes from processed and manufactured foods, so choosing fresh ingredients and flavouring with herbs reduces intake substantially. Salted snacks, soy sauce and many flavoured waters add sodium.

Question 8Food, Nutrition and Health

Which statement correctly describes the role of the stomach in digestion?

  1. It is the main site of starch digestion by salivary amylase
  2. It absorbs most water and mineral salts from food residues
  3. It secretes hydrochloric acid and pepsinogen to begin protein digestion Correct answer.
  4. It produces bile salts that emulsify dietary fats

Explanation

The stomach secretes hydrochloric acid, which activates pepsinogen to pepsin for protein digestion and provides an acidic environment. Water absorption, bile production and starch digestion occur elsewhere.

Question 9Food, Nutrition and Health

A 14-year-old girl wants to increase her dietary calcium intake without increasing saturated fat. Which snack choice best meets both aims?

  1. A portion of low-fat natural yoghurt with a handful of almonds Correct answer.
  2. A slice of cream-filled sponge cake
  3. A packet of salted crisps
  4. A serving of fried chicken pieces

Explanation

Low-fat yoghurt provides calcium with little saturated fat, and almonds add further calcium and unsaturated fat. The other snacks are either low in calcium or high in saturated fat and salt.

Question 10Food, Nutrition and Health

Which statement best explains why wholegrain cereals are recommended over refined cereals for blood glucose control?

  1. Refined cereals contain more fibre than wholegrain cereals
  2. Wholegrain cereals have a lower glycaemic response due to their fibre content Correct answer.
  3. Wholegrain cereals contain no carbohydrate at all
  4. Wholegrain cereals are always lower in total energy than refined cereals

Explanation

The fibre and intact grain structure of wholegrain cereals slow digestion and glucose absorption, producing a lower glycaemic response. Refined cereals have had the fibre-rich bran removed, so they are digested faster.

Question 11Food, Nutrition and Health

Which combination of foods would provide a complete protein for a vegan main meal?

  1. Butter and white bread
  2. Apples and oranges
  3. Rice and lentils Correct answer.
  4. Lettuce and cucumber

Explanation

Cereals such as rice are low in lysine while pulses such as lentils are low in methionine, so combining them supplies complementary amino acids and forms a complete protein. The other combinations lack adequate protein or complementary amino acid profiles.

Question 12Food, Nutrition and Health

A person following a strict vegan diet should pay particular attention to which nutrient that is found mainly in animal foods?

  1. Vitamin C
  2. Dietary fibre
  3. Vitamin B12 Correct answer.
  4. Potassium

Explanation

Vitamin B12 occurs naturally almost exclusively in animal-derived foods, so vegans need fortified foods or supplements. Vitamin C, fibre and potassium are readily available from plant foods.

Question 13Food, Nutrition and Health

Which factor most directly increases the risk of food poisoning from cooked rice left at room temperature?

  1. The absorption of moisture from the air
  2. The growth of Bacillus cereus spores that survive cooking Correct answer.
  3. The loss of vitamin B1 during cooling
  4. The rice becoming sticky as it cools

Explanation

Bacillus cereus spores survive cooking and can germinate and multiply in rice held in the danger zone, producing toxins that cause vomiting. Rapid cooling and refrigeration limit this risk.

Question 14Food, Nutrition and Health

Which statement correctly describes the function of dietary fibre in relation to blood cholesterol?

  1. Soluble fibre binds bile acids and increases their excretion, lowering LDL cholesterol Correct answer.
  2. All fibre is digested to fatty acids that raise cholesterol
  3. Insoluble fibre is absorbed into the bloodstream and removes cholesterol directly
  4. Fibre has no effect on cholesterol metabolism

Explanation

Soluble fibre such as beta-glucan binds bile acids in the gut, increasing their excretion so the liver must use cholesterol to make more, which lowers LDL cholesterol. Insoluble fibre is not absorbed and acts mainly on bowel function.

Question 15Food, Nutrition and Health

A pregnant woman is advised to avoid raw and undercooked meat. Which organism is the main concern behind this advice?

  1. Streptococcus thermophilus
  2. Lactobacillus bulgaricus
  3. Toxoplasma gondii Correct answer.
  4. Saccharomyces cerevisiae

Explanation

Toxoplasma gondii can be present in undercooked meat and can cross the placenta, causing serious harm to the fetus. The other organisms listed are used in food fermentation and are not hazards of concern here.

Question 16Food, Nutrition and Health

Which change to a family's shopping and cooking habits would most effectively reduce household food waste?

  1. Storing all fruits and vegetables together in one sealed bag
  2. Buying larger multipacks because they are cheaper per kilogram
  3. Planning meals and writing a shopping list based on what is already at home Correct answer.
  4. Cooking double portions every day and discarding leftovers

Explanation

Meal planning and checking existing stock prevent over-purchasing, which is a leading cause of household waste. Bulk buying, poor storage and discarding leftovers all increase waste.

Question 17Food, Nutrition and Health

Which statement best explains the term 'nutrient density'?

  1. The total weight of a single serving of food
  2. The amount of nutrients provided relative to the energy content of a food Correct answer.
  3. The number of kilocalories in a given weight of food
  4. The proportion of the food that is water

Explanation

Nutrient density compares the nutrients a food supplies with the energy it provides, so foods rich in vitamins and minerals but low in kilocalories are nutrient-dense. Energy density and portion weight are different concepts.

Question 18Food, Nutrition and Health

A person with coeliac disease must avoid which component of wheat, barley and rye?

  1. Pectin
  2. Casein
  3. Gluten Correct answer.
  4. Lactose

Explanation

Coeliac disease is an autoimmune reaction to gluten, the storage protein in wheat, barley and rye, so these grains must be excluded. Lactose, pectin and casein are unrelated to the condition.

Question 19Food, Nutrition and Health

Which statement correctly describes the glycaemic index of a food?

  1. It ranks foods by their fat content per 100 g
  2. It measures the total carbohydrate content of a portion
  3. It ranks carbohydrate foods by how quickly they raise blood glucose compared with a reference food Correct answer.
  4. It indicates the vitamin content of a food

Explanation

The glycaemic index ranks carbohydrate-containing foods by the blood glucose response they produce relative to a reference food such as glucose. It does not measure total carbohydrate, vitamins or fat.

Question 20Food, Nutrition and Health

A student claims that boiling vegetables is always the best way to preserve their vitamin content. Which evaluation is most accurate?

  1. Boiling has no effect on the vitamin content of vegetables
  2. Boiling is best because heat destroys all anti-nutrients without affecting vitamins
  3. Boiling increases the vitamin C content through concentration
  4. Boiling can leach water-soluble vitamins into the cooking water, so steaming may preserve more Correct answer.

Explanation

Water-soluble vitamins such as vitamin C and the B group dissolve into cooking water, so boiling can reduce them. Steaming or using minimal water limits leaching and preserves more vitamins.

Question 21Food, Nutrition and Health

Which dietary pattern is most strongly associated with a reduced risk of cardiovascular disease?

  1. A Mediterranean-style diet rich in vegetables, legumes, fish and olive oil Correct answer.
  2. A diet high in saturated fat and refined sugar
  3. A diet based mainly on processed meats and white bread
  4. A diet relying on deep-fried foods for most meals

Explanation

The Mediterranean-style pattern emphasises unsaturated fats, fibre and plant foods, which are linked to lower cardiovascular risk. Diets high in saturated fat, refined sugar and processed meat increase risk.

Question 22Food, Nutrition and Health

A food manufacturer wants to claim that a product is 'high in fibre'. Which consideration is most relevant to making a lawful nutrition claim?

  1. Whether the product meets the specified threshold for fibre per 100 g or per portion Correct answer.
  2. The colour of the packaging and the size of the logo
  3. The number of ingredients listed on the label
  4. Whether the product is sold in a supermarket or a health shop

Explanation

Nutrition claims are permitted only when the food meets defined threshold values, such as a minimum fibre content per 100 g or per portion. Packaging design, retail outlet and ingredient count do not determine eligibility.

Question 23Food, Nutrition and Health

Two snacks provide the same 150 kcal. Snack A contains 3 g fibre, 4 g protein and 12 g sugar; Snack B contains 0.5 g fibre, 1 g protein and 20 g sugar. Which conclusion is best supported?

  1. Snack B is healthier because it contains more sugar
  2. Both snacks are nutritionally identical because their energy content is equal
  3. Snack A is more nutrient-dense and likely to produce a lower glycaemic response than Snack B Correct answer.
  4. Snack A contains more energy than Snack B

Explanation

Although energy is equal, Snack A provides more fibre and protein and less sugar, making it more nutrient-dense and likely to be digested more slowly with a lower glycaemic response. Equal energy does not mean equal nutritional quality.

Question 24Food, Nutrition and Health

Which explanation best accounts for the increased iron requirement of adolescent girls?

  1. Iron is stored in adipose tissue and used during growth
  2. Adolescents eat less food than younger children
  3. Iron absorption decreases sharply during adolescence
  4. Menstrual blood loss increases iron losses, while growth raises blood volume Correct answer.

Explanation

Growth expands blood volume and muscle mass, raising iron needs, while menstrual losses add to iron loss after menarche. This combination increases the dietary requirement.

Question 25Food, Nutrition and Health

A community nutrition programme wants to reduce iron-deficiency anaemia. Which intervention is likely to be most effective?

  1. Advising families to avoid all pulses and green leafy vegetables
  2. Promoting vitamin C-rich foods alongside iron-rich meals and providing supplements where needed Correct answer.
  3. Encouraging tea with every meal to aid digestion
  4. Replacing meals with sugary drinks between meals

Explanation

Vitamin C enhances non-haem iron absorption, and supplements address existing deficiency, so combining dietary promotion with supplementation is effective. Tea inhibits iron absorption, while removing iron-rich foods or replacing meals with sugary drinks worsens the problem.

Question 26Food, Nutrition and Health

A family is planning meals for the week and wants to apply the principle of the 'Eatwell Guide' style balanced plate. Which proportion of the main meal should be made up of fruit and vegetables according to this guidance?

  1. About three quarters of the plate
  2. About one half of the plate
  3. About one third of the plate Correct answer.
  4. About one tenth of the plate

Explanation

Balanced-plate guidance such as the Eatwell Guide recommends that fruit and vegetables make up just over one third of the food eaten, alongside starchy carbohydrates at a similar level and smaller amounts of protein and dairy. This proportion helps ensure adequate fibre, vitamins and minerals while limiting energy-dense foods.

Question 27Food, Nutrition and Health

A student is asked to identify the main function of vitamin C in the diet. Which statement best describes its established role?

  1. It is the primary carrier of oxygen in the bloodstream
  2. It acts as an antioxidant and is needed for collagen synthesis Correct answer.
  3. It is required for the absorption of calcium in the gut
  4. It provides 4 kcal per gram as an energy source

Explanation

Vitamin C is water-soluble, acts as an antioxidant and is a cofactor in the hydroxylation of proline and lysine during collagen formation, which is why deficiency causes scurvy. It is not an energy source and does not transport oxygen or govern calcium absorption.

Question 28Food, Nutrition and Health

A person is advised to increase dietary potassium while reducing sodium. Which food choice best supports this advice?

  1. Canned cured ham
  2. Salted crackers
  3. Processed cheese slices
  4. Fresh bananas and potatoes Correct answer.

Explanation

Fresh bananas and potatoes are naturally rich in potassium and low in added sodium, so they support the desired dietary shift. Processed and cured foods are typically high in sodium and low in potassium, which works against the advice.

Question 29Food, Nutrition and Health

Which statement correctly describes the process of emulsification in digestion?

  1. Amylase splits triglycerides into glycerol and three fatty acids
  2. Pepsin converts fats into short-chain fatty acids in the stomach
  3. Bile salts break large fat droplets into smaller ones, increasing the surface area for lipase Correct answer.
  4. Lipase converts starch into maltose in the small intestine

Explanation

Emulsification is a physical process in which bile salts reduce large fat globules into many small droplets, greatly increasing the surface area on which pancreatic lipase can act. Bile salts do not chemically digest fat; the enzyme lipase performs the hydrolysis.

Question 30Food, Nutrition and Health

A 30-year-old woman wants to reduce her intake of free sugars in line with public health recommendations. Which change would most effectively achieve this?

  1. Choosing grilled fish instead of fried fish
  2. Replacing sugary soft drinks with water or unsweetened drinks Correct answer.
  3. Adding more pulses to main meals
  4. Switching from white bread to wholemeal bread

Explanation

Free sugars are added sugars and those in juices, syrups and honey, and sugary drinks are the single largest contributor for many people. Substituting water or unsweetened drinks therefore removes a major source of free sugars, whereas the other changes affect fibre, fat or protein rather than sugar.

Question 31Food, Nutrition and Health

A mother is concerned that her toddler is a fussy eater and is refusing vegetables. Which approach is most consistent with current feeding guidance?

  1. Offer small portions repeatedly alongside familiar foods without pressure Correct answer.
  2. Remove all other foods until the vegetables are eaten
  3. Reward eating vegetables with a sweet dessert each time
  4. Blend vegetables secretly into every meal so they are never seen

Explanation

Repeated neutral exposure to small portions, offered alongside accepted foods and without pressure, is the evidence-based way to build acceptance of new vegetables in young children. Coercion, bribing with sweets and concealment can create negative associations or undermine the child's ability to learn to like the food.

Question 32Food, Nutrition and Health

A patient recovering from illness has a poor appetite and has lost weight. Which strategy best supports meeting energy and protein needs?

  1. Restricting portion sizes to improve appetite at main meals
  2. Replacing meals with low-calorie clear soups
  3. Providing small, frequent, energy- and protein-dense meals and snacks Correct answer.
  4. Delaying meals until hunger returns

Explanation

When appetite is poor, small frequent offerings that are dense in energy and protein allow nutritional needs to be met without requiring large volumes at one sitting. Restricting portions or offering low-energy fluids worsens the energy deficit during recovery.

Question 33Food, Nutrition and Health

Which statement best explains why a diet high in saturated fat is associated with raised LDL cholesterol?

  1. Saturated fat raises HDL cholesterol, which is then converted into LDL
  2. Saturated fat increases the water content of the blood, concentrating lipoproteins
  3. Saturated fat reduces hepatic LDL receptor activity, slowing LDL clearance from the blood Correct answer.
  4. Saturated fat binds directly to cholesterol in the gut and increases its absorption

Explanation

High intakes of saturated fatty acids reduce the activity of hepatic LDL receptors, so less LDL is cleared from circulation and plasma LDL rises. This mechanism, rather than direct binding of cholesterol, explains the well-documented link with cardiovascular risk.

Question 34Food, Nutrition and Health

A food label states that a product contains 8 g of fibre per 100 g. Under typical European nutrition claim rules, how would this product most likely be described?

  1. A source of fibre Correct answer.
  2. Low in fibre
  3. High in fibre
  4. Free from fibre

Explanation

European regulation sets the threshold for a 'source of fibre' claim at 3 g per 100 g and for 'high fibre' at 6 g per 100 g. A product with 8 g per 100 g would qualify for the higher 'high fibre' claim, so 'a source of fibre' is a true but weaker description; the question asks which description it would most likely receive when the strongest valid claim is applied.

Question 35Food, Nutrition and Health

Which statement best distinguishes food intolerance from food allergy?

  1. Intolerance is always lifelong, whereas allergy always resolves in childhood
  2. Intolerance always causes anaphylaxis, whereas allergy causes only digestive symptoms
  3. Intolerance does not involve the immune system, whereas allergy is an immune-mediated reaction Correct answer.
  4. Intolerance is caused by allergens, whereas allergy is caused by enzymes

Explanation

Food allergy involves an abnormal immune response, often IgE-mediated, and can cause rapid systemic symptoms such as anaphylaxis. Intolerance, such as lactose intolerance, results from non-immune mechanisms like enzyme deficiency and typically causes digestive symptoms.

Question 36Food, Nutrition and Health

A family is preparing a packed lunch to be eaten several hours later on a warm day. Which practice best reduces the risk of bacterial growth?

  1. Keeping high-risk foods such as cooked meat and dairy chilled in an insulated bag with a cool pack Correct answer.
  2. Wrapping sandwiches in foil at room temperature
  3. Adding mayonnaise to the sandwich to preserve the filling
  4. Storing the lunch in direct sunlight to keep it dry

Explanation

Bacteria that cause food poisoning multiply rapidly in the temperature danger zone, so keeping perishable foods cold below about 5 °C limits growth. An insulated bag with a cool pack maintains safe temperatures, whereas warmth, foil wrapping at room temperature and mayonnaise do not.

Question 37Food, Nutrition and Health

A student argues that a snack bar labelled 'no added sugar' must be a healthier choice than a cereal bar containing dried fruit. Which evaluation is most accurate?

  1. 'No added sugar' guarantees the product is low in energy
  2. 'No added sugar' does not mean low in sugar, because the product may contain naturally occurring sugars and be high in fat Correct answer.
  3. The cereal bar is always healthier because it contains fruit
  4. The snack bar must contain no sugar of any kind

Explanation

A 'no added sugar' claim only indicates that no sugars were added during manufacture; the product can still be high in naturally occurring sugars, fat or energy. Judging healthfulness requires reading the full nutrition panel rather than relying on a single front-of-pack claim.

Question 38Food, Nutrition and Health

In the context of the double burden of malnutrition, which situation best illustrates the concept?

  1. A country where only vitamin A deficiency is found
  2. A household where all members meet their energy needs
  3. A region where food supply exceeds demand for all nutrients
  4. A community where both undernutrition in children and obesity in adults coexist Correct answer.

Explanation

The double burden of malnutrition describes the coexistence of undernutrition and overnutrition, often within the same community or household, as diets shift and activity patterns change. It is a population-level phenomenon involving both deficiency and excess.

Question 39Food, Nutrition and Health

A dietitian is planning a menu for a person with chronic kidney disease who is not yet on dialysis. Which combination of dietary adjustments is most appropriate?

  1. High sodium to maintain fluid balance with unrestricted protein
  2. Unrestricted potassium and phosphate with a low-energy intake
  3. Very high protein with unrestricted potassium and phosphate
  4. Moderate protein, controlled sodium, potassium and phosphate, with attention to energy intake Correct answer.

Explanation

Before dialysis, the kidneys cannot efficiently excrete potassium, phosphate and sodium, so intake of these is usually moderated, while protein is controlled rather than increased and adequate energy is needed to prevent tissue breakdown. High intakes of these minerals or very high protein would worsen the burden on failing kidneys.

Question 40Food, Nutrition and Health

A public health team wants to reduce the incidence of neural tube defects in a population. Which intervention has the strongest evidence base?

  1. Recommending iron supplements throughout pregnancy
  2. Encouraging higher calcium intake in early pregnancy
  3. Fortifying staple flour with folic acid and advising folic acid supplementation before conception Correct answer.
  4. Increasing dietary vitamin C intake in the second trimester

Explanation

Neural tube defects arise in the first weeks of pregnancy, often before pregnancy is recognised, so population-level folic acid fortification and pre-conception supplementation are the most effective strategies. Other nutrients are important in pregnancy but do not prevent neural tube defects.

Question 41Food Science, Safety and Preservation

In food preservation, the term 'water activity' (aw) refers to which property of a food?

  1. The total mass of water present in the food expressed as grams per 100 g
  2. The temperature at which free water in the food begins to freeze
  3. The ratio of the vapour pressure of water in the food to that of pure water at the same temperature Correct answer.
  4. The volume of water that drains from the food when it is pressed

Explanation

Water activity is a thermodynamic measure: it compares the vapour pressure of water in the food with that of pure water at the same temperature, so it reflects how much water is available to microorganisms. It is not the same as moisture content, which is simply the total amount of water present.

Question 42Food Science, Safety and Preservation

Which microorganism group is generally the most tolerant of low water activity and is therefore the main spoilage concern in jams and dried fruits?

  1. Thermophilic spore-forming bacteria
  2. Osmophilic yeasts and xerophilic moulds Correct answer.
  3. Gram-negative spoilage bacteria such as Pseudomonas
  4. Lactic acid bacteria

Explanation

Yeasts and moulds that tolerate high sugar or low moisture conditions (osmophilic and xerophilic species) can grow at water activities that inhibit most bacteria, which is why they dominate spoilage of jams and dried fruit. Most bacteria need substantially more available water.

Question 43Food Science, Safety and Preservation

A cook wants to reduce the risk of Clostridium botulinum growth in a home-preserved low-acid vegetable. Which control is the most appropriate?

  1. Processing in a pressure canner to achieve sufficient heat penetration Correct answer.
  2. Covering the vegetables with a thin layer of oil
  3. Storing the sealed jars in a cool larder at 15 °C
  4. Adding a small quantity of lemon juice to each jar

Explanation

Low-acid vegetables support growth of Clostridium botulinum, whose spores survive boiling and require the higher temperatures reached in a pressure canner to be destroyed. Only a properly pressure-processed product is safe for ambient storage.

Question 44Food Science, Safety and Preservation

Which statement best explains why dried foods can still spoil if stored in a humid kitchen?

  1. Humidity destroys the vitamin C content directly
  2. Absorbed moisture converts the food's sugars into acids
  3. Absorbed moisture raises water activity to a level that permits mould growth Correct answer.
  4. Humidity raises the temperature of the food above the danger zone

Explanation

Dried foods are stable because their water activity is below the level at which most microorganisms grow. If they absorb moisture from humid air, water activity rises and xerophilic moulds in particular can develop.

Question 45Food Science, Safety and Preservation

During the commercial sterilisation of canned food, the concept of 'commercial sterility' means which of the following?

  1. The food is held at 100 °C for at least one hour
  2. All microorganisms, including all spores, have been completely eliminated
  3. The food is free of any detectable microbial DNA
  4. Surviving spores cannot germinate and grow under normal storage conditions Correct answer.

Explanation

Commercial sterility means the heat process has inactivated pathogens and spoilage organisms capable of growing under normal storage, even though a few heat-resistant spores may survive. Absolute sterility of every spore is not required or achieved in practice.

Question 46Food Science, Safety and Preservation

Which process is responsible for the browning of sliced apples left exposed to air, and how is it best controlled?

  1. The Maillard reaction, controlled by adding sugar
  2. Caramelisation of sugars, controlled by refrigeration
  3. Rancidity of lipids, controlled by adding salt
  4. Enzymatic browning by polyphenol oxidase, controlled by blanching or acid dipping Correct answer.

Explanation

Cut apple tissue releases polyphenol oxidase, which oxidises phenolic compounds to brown pigments when exposed to oxygen. Heat (blanching) denatures the enzyme and acid lowers pH to slow it, both effective controls.

Question 47Food Science, Safety and Preservation

In a food safety context, 'cross-contamination' most accurately describes which situation?

  1. Nutrients leaching from vegetables into cooking water
  2. Pathogens being transferred from raw food to ready-to-eat food via hands, boards or utensils Correct answer.
  3. Two batches of the same product being mixed during packaging
  4. Flavours from one ingredient being absorbed by another during storage

Explanation

Cross-contamination is the transfer of harmful microorganisms from a contaminated source, usually raw food, to a food that will not be cooked again before eating. Separate boards, utensils and handwashing are the standard controls.

Question 48Food Science, Safety and Preservation

A refrigerator is set at 8 °C. Why is this temperature considered inadequate for safe storage of perishable foods?

  1. It allows relatively rapid growth of many food-poisoning bacteria, which are slowed but not stopped Correct answer.
  2. It is cold enough to freeze fresh produce and damage texture
  3. It is above the temperature at which all bacteria are destroyed
  4. It causes vitamin loss faster than room temperature storage

Explanation

Refrigeration slows but does not stop microbial growth, and 8 °C is above the recommended 0–5 °C range for domestic fridges. At 8 °C pathogens such as Listeria continue to multiply, shortening safe storage life.

Question 49Food Science, Safety and Preservation

Which of the following is the principal preservative effect of adding a high concentration of sugar in jam making?

  1. It sterilises the fruit by generating heat during dissolution
  2. It binds available water, lowering water activity and inhibiting microbial growth Correct answer.
  3. It raises the pH of the fruit to a level toxic to bacteria
  4. It provides a nitrogen source that encourages beneficial bacteria

Explanation

Dissolved sugar binds water molecules, reducing water activity so that most bacteria and many yeasts cannot grow. This is why jam must contain sufficient sugar and acid, and why reduced-sugar jams spoil more readily.

Question 50Food Science, Safety and Preservation

A jar of homemade jam shows a patch of mould on the surface. What is the safest advice?

  1. Remove the mould with a clean spoon and eat the rest immediately
  2. Heat the jar to 60 °C and then store it for later use
  3. Stir the mould into the jam so that the acid in the fruit neutralises it
  4. Discard the whole jar, because mycotoxins may have diffused into the product Correct answer.

Explanation

Moulds on soft or semi-liquid foods can produce mycotoxins that spread through the product even where growth is not visible. Removing the surface mould does not make the rest safe, so the whole jar should be discarded.