৪৯তম বিসিএস ⎯ গার্হস্থ্য অর্থনীতি [৩৯১]

Types of food spoilage & characteristics of spoiled foods. খাবার নষ্ট হওয়ার ধরণ এবং নষ্ট খাবারের বৈশিষ্ট্য।
1. Yeast
Single-celled microorganisms.
Grow in sweets, pickles, syrups, jams, jellies in the presence of moisture and air.
Use carbohydrates for growth.
Convert sugars into alcohol + CO₂ → food becomes bubbly and smells bad.
Cannot survive in very high temperature or dry conditions.
Optimum growth: 20–30°C with moisture.

Enzymes
Protein-based biological catalysts present in plants and animals.
Help in ripening of fruits (convert starch → sugar, making fruits sweeter).
Activity increases with higher temperature.
Become inactive at 35–40°C, destroyed above 80°C.
In presence of air and light, enzymes act faster.
After harvesting crops or cutting meat, enzymes can spoil food by producing acids and gases.

Caution During Preparing Food
Dirty hands, clothes, or utensils contaminate food with germs.
Fish and meat should be cooked as soon as possible after buying; if left exposed, they smell bad and develop germs.
Domestic animals (cats, poultry) and pests (flies, cockroaches) contaminate food with saliva, droppings, and germs → cause diarrhea, cholera, typhoid.
Vegetables, fish, and meat should not be soaked in water too long → vitamins and minerals are lost.
Throwing away rice water (mār) removes Thiamine (Vitamin B₁) → causes deficiency diseases.
Kitchen must be clean, dry, well-ventilated.
Utensils must be washed with clean water before use.
Cough, cold, or wounds of cooks can contaminate food.

Principles and methods of food preservation
খাদ্য সংরক্ষণের নীতি ও পদ্ধতি।
Main Principle: Food should be processed and stored in a way that prevents spoilage and maintains its quality. The primary goals are:
Inhibit the growth of microorganisms (bacteria, yeast, fungi)
Reduce enzyme activity
Minimize exposure to air or moisture

According to Bangladesh Economic Review,
Studies show that about 70% of Bangladeshis are Vitamin D deficient.
Causes:Lack of adequate sun exposure (indoor lifestyle, clothing covering most skin).
Rice-dominated diet with very few Vitamin D–rich foods (like fatty fish, eggs, fortified milk).
Effects:Weak bones, rickets in children, osteoporosis in adults.
Weak immunity and higher risk of chronic diseases.

PEM stands for Protein-Energy Malnutrition
Cause: Long-term deficiency of protein and calories in the diet.
Forms:
Kwashiorkor → mainly protein deficiency (swollen belly, edema).
Marasmus → severe deficiency of both protein and calories (extreme thinness, wasted muscles).
Effect:
Stunted growth in children
Weakness, low immunity
Developmental delays

Caution During Preparing Food
Dirty hands, clothes, or utensils contaminate food with germs.
Fish and meat should be cooked as soon as possible after buying; if left exposed, they smell bad and develop germs.
Domestic animals (cats, poultry) and pests (flies, cockroaches) contaminate food with saliva, droppings, and germs → cause diarrhea, cholera, typhoid.
Vegetables, fish, and meat should not be soaked in water too long → vitamins and minerals are lost.
Throwing away rice water (mār) removes Thiamine (Vitamin B₁) → causes deficiency diseases.
Kitchen must be clean, dry, well-ventilated.
Utensils must be washed with clean water before use.
Cough, cold, or wounds of cooks can contaminate food.

Caution During Cooking
Cooking makes food digestible, tasty, and germ-free.
Hands and utensils must be cleaned before cooking.
Wash vegetables and fruits properly before cutting.
Cut and cook food immediately (avoid delay).
Best method: Cook in covered pots, high heat, short time with minimum water → preserves color, flavor, and nutrition.
Do not throw away water used for cooking rice, meat, liver, or vegetables → it contains vitamins and minerals.
Overheating eggs or long boiling destroys nutrition.
Meat should be cooked at medium heat, covered, slowly → soft and digestible.
Excess onion, spices, and alkali (soda) destroy food’s nutrients (e.g., soda destroys vitamins in pulses).
Whenever possible, eat vegetables and fruits raw (cucumber, carrot, tomato, lettuce, radish).

Principles and methods of food preservation
খাদ্য সংরক্ষণের নীতি ও পদ্ধতি।
Main Principle: Food should be processed and stored in a way that prevents spoilage and maintains its quality. The primary goals are:
Inhibit the growth of microorganisms (bacteria, yeast, fungi)
Reduce enzyme activity
Minimize exposure to air or moisture

PEM stands for Protein-Energy Malnutrition
Cause: Long-term deficiency of protein and calories in the diet.
Forms:
Kwashiorkor → mainly protein deficiency (swollen belly, edema).
Marasmus → severe deficiency of both protein and calories (extreme thinness, wasted muscles).
Effect:
Stunted growth in children
Weakness, low immunity
Developmental delays

Types of food spoilage & characteristics of spoiled foods. খাবার নষ্ট হওয়ার ধরণ এবং নষ্ট খাবারের বৈশিষ্ট্য।
1. Yeast
Single-celled microorganisms.
Grow in sweets, pickles, syrups, jams, jellies in the presence of moisture and air.
Use carbohydrates for growth.
Convert sugars into alcohol + CO₂ → food becomes bubbly and smells bad.
Cannot survive in very high temperature or dry conditions.
Optimum growth: 20–30°C with moisture.

Enzymes
Protein-based biological catalysts present in plants and animals.
Help in ripening of fruits (convert starch → sugar, making fruits sweeter).
Activity increases with higher temperature.
Become inactive at 35–40°C, destroyed above 80°C.
In presence of air and light, enzymes act faster.
After harvesting crops or cutting meat, enzymes can spoil food by producing acids and gases.

Maintaining Nutritional Value During Cooking
Cereals (rice, wheat, corn, pulses):
Wash lightly before cooking (not too much).
Do not discard cooking water → it contains vitamins and minerals.
Cook pulses (dal) properly, but avoid soaking too long or discarding water.
Fish:
Soft protein → cook at low temperature for short time.
During frying, fish must be fully dipped in oil to avoid nutrient loss.
Meat:
Rich protein source.
Should be cooked at around 80°C slowly with cover to avoid protein hardening and vitamin loss.
Larger meat pieces help preserve nutrients.
Avoid too much oil and spices.

Principles and methods of food preservation
খাদ্য সংরক্ষণের নীতি ও পদ্ধতি।
Main Principle: Food should be processed and stored in a way that prevents spoilage and maintains its quality. The primary goals are:
Inhibit the growth of microorganisms (bacteria, yeast, fungi)
Reduce enzyme activity
Minimize exposure to air or moisture

PEM stands for Protein-Energy Malnutrition
Cause: Long-term deficiency of protein and calories in the diet.
Forms:
Kwashiorkor → mainly protein deficiency (swollen belly, edema).
Marasmus → severe deficiency of both protein and calories (extreme thinness, wasted muscles).
Effect:
Stunted growth in children
Weakness, low immunity
Developmental delays

Pasteurization is a food preservation method in which food (such as milk, juice, or liquid products) is heated to a specific temperature for a fixed time and then cooled immediately.

The purpose is to kill harmful microorganisms like bacteria, yeast, and molds.

However, pasteurization does not destroy all microorganisms – it mainly destroys the pathogenic (disease-causing) microbes, making food safe for consumption and extending its shelf life.

Example: Milk is often pasteurized at 72°C for 15 seconds (known as HTST – High Temperature Short Time method).

Maintaining Nutritional Value During Cooking
Cereals (rice, wheat, corn, pulses):
Wash lightly before cooking (not too much).
Do not discard cooking water → it contains vitamins and minerals.
Cook pulses (dal) properly, but avoid soaking too long or discarding water.
Fish:
Soft protein → cook at low temperature for short time.
During frying, fish must be fully dipped in oil to avoid nutrient loss.
Meat:
Rich protein source.
Should be cooked at around 80°C slowly with cover to avoid protein hardening and vitamin loss.
Larger meat pieces help preserve nutrients.
Avoid too much oil and spices.

Types of food spoilage & characteristics of spoiled foods. খাবার নষ্ট হওয়ার ধরণ এবং নষ্ট খাবারের বৈশিষ্ট্য।
2. Bacteria
Microscopic single-celled organisms.
Grow well in warm and moist environments.
Produce toxins → cause food poisoning.
Found in meat, fish, and protein-rich foods, making them slimy, soft, and foul-smelling (ammonia, H₂S).
Some bacteria are beneficial (e.g., Lactobacillus in yogurt and cheese).
Types by temperature:
Microphilic – grow at ~20°C
Mesophilic – grow at 20–80°C
Thermophilic – grow above 80°C

Main Methods of Food Preservation:
Heat Processing
Pasteurization: Heating food (like milk) to a specific temperature for a set time, then rapidly cooling it. Destroys harmful microbes but retains nutrients.
Boiling: Cooking food (vegetables, fruits, meat) to destroy microbes and spores.
Canning: Sealing food in cans and heating to destroy microbes and prevent air entry.
Cold Processing
Refrigeration: Storing food at 0°–4°C to slow microbial growth.
Freezing: Storing food at −18°C or lower to stop microbial growth and extend shelf life.

PEM stands for Protein-Energy Malnutrition
Cause: Long-term deficiency of protein and calories in the diet.
Forms:
Kwashiorkor → mainly protein deficiency (swollen belly, edema).
Marasmus → severe deficiency of both protein and calories (extreme thinness, wasted muscles).
Effect:
Stunted growth in children
Weakness, low immunity
Developmental delays

IDD refers to a group of health problems that occur due to lack of iodine in the diet.

Major Effects of IDD

Goitre (গয়টার): Enlargement of the thyroid gland → visible swelling in the neck.

Cretinism (ক্রেটিনিজম): Severe mental and physical retardation in children (if mother had iodine deficiency during pregnancy).

Reduced IQ (বুদ্ধিমত্তা হ্রাস): Lower learning ability and poor school performance.

Stillbirth & Miscarriage (গর্ভপাত ও মৃতশিশুর জন্ম): High risk during pregnancy.

Growth & Development Problems (বৃদ্ধি ও বিকাশে সমস্যা): Especially in children.

Enzymes
Protein-based biological catalysts present in plants and animals.
Help in ripening of fruits (convert starch → sugar, making fruits sweeter).
Activity increases with higher temperature.
Become inactive at 35–40°C, destroyed above 80°C.
In presence of air and light, enzymes act faster.
After harvesting crops or cutting meat, enzymes can spoil food by producing acids and gases.

Main Methods of Food Preservation:
Heat Processing
Pasteurization: Heating food (like milk) to a specific temperature for a set time, then rapidly cooling it. Destroys harmful microbes but retains nutrients.
Boiling: Cooking food (vegetables, fruits, meat) to destroy microbes and spores.
Canning: Sealing food in cans and heating to destroy microbes and prevent air entry.
Cold Processing
Refrigeration: Storing food at 0°–4°C to slow microbial growth.
Freezing: Storing food at −18°C or lower to stop microbial growth and extend shelf life.

Types of food spoilage & characteristics of spoiled foods. খাবার নষ্ট হওয়ার ধরণ এবং নষ্ট খাবারের বৈশিষ্ট্য।
2. Bacteria
Microscopic single-celled organisms.
Grow well in warm and moist environments.
Produce toxins → cause food poisoning.
Found in meat, fish, and protein-rich foods, making them slimy, soft, and foul-smelling (ammonia, H₂S).
Some bacteria are beneficial (e.g., Lactobacillus in yogurt and cheese).
Types by temperature:
Microphilic – grow at ~20°C
Mesophilic – grow at 20–80°C
Thermophilic – grow above 80°C

PEM stands for Protein-Energy Malnutrition
Cause: Long-term deficiency of protein and calories in the diet.
Forms:
Kwashiorkor → mainly protein deficiency (swollen belly, edema).
Marasmus → severe deficiency of both protein and calories (extreme thinness, wasted muscles).
Effect:
Stunted growth in children
Weakness, low immunity
Developmental delays

IDD refers to a group of health problems that occur due to lack of iodine in the diet.

Major Effects of IDD

Goitre (গয়টার): Enlargement of the thyroid gland → visible swelling in the neck.

Cretinism (ক্রেটিনিজম): Severe mental and physical retardation in children (if mother had iodine deficiency during pregnancy).

Reduced IQ (বুদ্ধিমত্তা হ্রাস): Lower learning ability and poor school performance.

Stillbirth & Miscarriage (গর্ভপাত ও মৃতশিশুর জন্ম): High risk during pregnancy.

Growth & Development Problems (বৃদ্ধি ও বিকাশে সমস্যা): Especially in children.

Types of food spoilage & characteristics of spoiled foods. খাবার নষ্ট হওয়ার ধরণ এবং নষ্ট খাবারের বৈশিষ্ট্য।
2. Bacteria
Microscopic single-celled organisms.
Grow well in warm and moist environments.
Produce toxins → cause food poisoning.
Found in meat, fish, and protein-rich foods, making them slimy, soft, and foul-smelling (ammonia, H₂S).
Some bacteria are beneficial (e.g., Lactobacillus in yogurt and cheese).
Types by temperature:
Microphilic – grow at ~20°C
Mesophilic – grow at 20–80°C
Thermophilic – grow above 80°C

Maintaining Nutritional Value During Cooking
Cereals (rice, wheat, corn, pulses):
Wash lightly before cooking (not too much).
Do not discard cooking water → it contains vitamins and minerals.
Cook pulses (dal) properly, but avoid soaking too long or discarding water.
Fish:
Soft protein → cook at low temperature for short time.
During frying, fish must be fully dipped in oil to avoid nutrient loss.
Meat:
Rich protein source.
Should be cooked at around 80°C slowly with cover to avoid protein hardening and vitamin loss.
Larger meat pieces help preserve nutrients.
Avoid too much oil and spices.

Enzymes
Protein-based biological catalysts present in plants and animals.
Help in ripening of fruits (convert starch → sugar, making fruits sweeter).
Activity increases with higher temperature.
Become inactive at 35–40°C, destroyed above 80°C.
In presence of air and light, enzymes act faster.
After harvesting crops or cutting meat, enzymes can spoil food by producing acids and gases.

Cold Processing (শীতলীকরণ দ্বারা সংরক্ষণ)

Refrigeration (রেফ্রিজারেশন):
Storing food at 0°–4°C slows down microbial growth.
→ Preserves perishable items like milk, vegetables, fruits for a few days.

Freezing (হিমায়ন):
Storing food at −18°C or below stops microbial growth completely.
→ Keeps food safe and fresh for weeks to months.

IDD refers to a group of health problems that occur due to lack of iodine in the diet.
Situation in Bangladesh
Bangladesh once had a very high prevalence of goitre.
Salt iodization program has reduced IDD significantly.
But risk still remains, especially in remote or poor areas

5.Moisture Removal
Drying: Removing water using sunlight or mechanical methods (e.g., dried fish, vegetables, fruits, grains).
Smoking: Hanging food over smoke; chemicals in smoke help prevent microbial growth (e.g., smoked fish or meat).
6.Chemical Preservation
Salting: Salt prevents microbial growth; used for pickles, meat, fish.
Sugaring: High sugar concentration prevents microbial growth; used for jams, jellies, preserves.
Using Oil & Vinegar: Acts as a barrier to air; vinegar’s acidity prevents microbial growth; commonly used for pickles.
7.Air Removal
Vacuum Packaging: Removing air from packaging slows microbial growth and oxidation.

IDA is a condition caused by insufficient iron in the body, leading to a reduced number of healthy red blood cells (hemoglobin deficiency).
Symptoms (উপসর্গ):Weakness, fatigue,Pale skin,Dizziness, headache,Reduced immunity,Poor growth in children.
Situation in Bangladesh
IDA is very common among women and adolescents, especially pregnant mothers.
One of the major public health issues.

Stunting means a child is too short for their age compared to the standard growth chart.
It reflects chronic malnutrition over a long period of time.
Causes:
Long-term lack of protein, vitamins, and minerals
Repeated infections (e.g., diarrhea, parasitic diseases)
Poor maternal nutrition during pregnancy
Inadequate child feeding practices

Enzymes
Protein-based biological catalysts present in plants and animals.
Help in ripening of fruits (convert starch → sugar, making fruits sweeter).
Activity increases with higher temperature.
Become inactive at 35–40°C, destroyed above 80°C.
In presence of air and light, enzymes act faster.
After harvesting crops or cutting meat, enzymes can spoil food by producing acids and gases.

Lactobacillus (ল্যাক্টোব্যাসিলাস)
In yogurt: Lactobacillus bulgaricus + Streptococcus thermophilus work together to ferment milk sugar (lactose) into lactic acid, giving yogurt its sour taste.
In cheese: Different strains of Lactobacillus help in acid formation, flavor development, and texture.

IDA is a condition caused by insufficient iron in the body, leading to a reduced number of healthy red blood cells (hemoglobin deficiency).
Symptoms (উপসর্গ):Weakness, fatigue,Pale skin,Dizziness, headache,Reduced immunity,Poor growth in children.
Situation in Bangladesh
IDA is very common among women and adolescents, especially pregnant mothers.
One of the major public health issues.

Zinc Deficiency Etiology: Diets heavily dependent on rice and cereals (low bioavailable zinc). Manifestations: Impaired immunity, poor growth, delayed wound healing.

Bacteria
Microscopic single-celled organisms.
Grow well in warm and moist environments.
Produce toxins → cause food poisoning.
Found in meat, fish, and protein-rich foods, making them slimy, soft, and foul-smelling (ammonia, H₂S).
Some bacteria are beneficial (e.g., Lactobacillus in yogurt and cheese).
Types by temperature:
Microphilic – grow at ~20°C
Mesophilic – grow at 20–80°C
Thermophilic – grow above 80°C

COVID-19 (Coronavirus) Awareness

•Other name: 2019-nCoV or Novel Coronavirus.
•Incubation period: 14–24 days.
•Main symptoms: Fever, dry cough, breathing difficulties (attacks lungs).
Prevention:

•Soak vegetables/fruits in salt or vinegar water for 30 minutes.
•Wash and cook food properly.
•Maintain personal hygiene → wash hands with soap for at least 20 seconds.
•Do not touch eyes, nose, or mouth without washing hands.

Weight and Height
Purpose: Detects wasting (acute malnutrition).
Interpretation: Low weight relative to height indicates recent weight loss or inadequate nutrition.
•Weight-for-Height: Used acutely to assess wasting (acute malnutrition).
•Height-for-Age: Used to assess stunting (chronic malnutrition).
•Body Mass Index (BMI): Weight (kg) / Height (m²). The most common adult index for classifying underweight, normal weight, overweight, and obesity.

Caution During Preparing Food
Dirty hands, clothes, or utensils contaminate food with germs.
Fish and meat should be cooked as soon as possible after buying; if left exposed, they smell bad and develop germs.
Domestic animals (cats, poultry) and pests (flies, cockroaches) contaminate food with saliva, droppings, and germs → cause diarrhea, cholera, typhoid.
Vegetables, fish, and meat should not be soaked in water too long → vitamins and minerals are lost.
Throwing away rice water (mār) removes Thiamine (Vitamin B₁) → causes deficiency diseases.
Kitchen must be clean, dry, well-ventilated.
Utensils must be washed with clean water before use.
Cough, cold, or wounds of cooks can contaminate food.

Molds (Fungi)
Appear as green/grey layers on foods.
Grow in damp, acidic, and poorly stored foods such as bread, cheese, jam, pickles, oranges, tomatoes.
Some molds on grains and peanuts produce dangerous toxins (e.g., aflatoxin).
Destroy taste, smell, and appearance of food.
Cannot grow in high temperature.
Prevention: Store food in dry, cool, airtight containers with good ventilation and light.

Wasting means a child has low weight for their height. It reflects acute malnutrition (short-term severe undernutrition).
Causes:
Sudden lack of food / famine
Severe illness or infections (e.g., diarrhea, pneumonia, measles)
Poor feeding during sickness
Emergency situations (floods, disasters, conflict)

•Body Mass Index (BMI): Weight (kg) / Height (m²). The most common adult index for classifying underweight, normal weight, overweight, and obesity.
Purpose: Common adult index for classifying nutritional status.

Classification (WHO Standard):

BMI (kg/m²)    Category
< 18.5    Underweight
18.5–24.9    Normal weight
25–29.9    Overweight
≥ 30    Obese

Molds (Fungi)
Appear as green/grey layers on foods.
Grow in damp, acidic, and poorly stored foods such as bread, cheese, jam, pickles, oranges, tomatoes.
Some molds on grains and peanuts produce dangerous toxins (e.g., aflatoxin).
Destroy taste, smell, and appearance of food.
Cannot grow in high temperature.
Prevention: Store food in dry, cool, airtight containers with good ventilation and light.

Anthropometric Methods (নৃতাত্ত্বিক পদ্ধতি):This method measures physical dimensions and body composition of an individual. It is:

Objective – not based on opinion.

Quantitative – produces measurable data.

Relatively easy to perform – requires simple tools like a weighing scale, stadiometer, or measuring tape.

Major Types of Malnutrition in Bangladesh:
Protein-Energy Malnutrition (PEM): Due to long-term lack of protein and calories.
Stunting: Low height for age (about 28% of children).
Wasting: Low weight for height (about 10% of children).
Iron Deficiency Anemia (IDA): Common among pregnant women and adolescents; causes weakness, fatigue, and reduced immunity.
Iodine Deficiency Disorders (IDD): Can lead to goitre and impaired mental development in children. Salt iodization programs have reduced prevalence but risks remain.
Other Micronutrient Deficiencies:
Vitamin A: Deficiency causes night blindness in children; supplementation programs have helped.
Vitamin D: Around 70% of Bangladeshis are deficient.
Zinc: Important for immunity; deficiency common due to rice-dominated diet.

During Food Preparation
Soak vegetables/fruits in vinegar water 30 minutes → then dry and store in fridge.
Wash raw foods with pure water before cooking.
Boil milk, pulses, fish, meat properly.
Wash hands with soap and keep nails short.
Utensils and cooking space must be clean.
Keep food covered while cooking.
(c) During Food Storage
Store food in clean, covered containers.
Use sealed packets/containers in fridge.
Always keep food covered to avoid flies, insects, dust.
Store dry foods (rice, pulses, flour) in sealed tins/bags in cool dry places.

Molds (Fungi)
Appear as green/grey layers on foods.
Grow in damp, acidic, and poorly stored foods such as bread, cheese, jam, pickles, oranges, tomatoes.
Some molds on grains and peanuts produce dangerous toxins (e.g., aflatoxin).
Destroy taste, smell, and appearance of food.
Cannot grow in high temperature.
Prevention: Store food in dry, cool, airtight containers with good ventilation and light.