High Temperature & Low Temperature /: slideshare

Food Microbiology

1. VIVEKANANDHA
ARTS AND SCIENCE COLLEGE FOR WOMEN
Veerachipalayam- 637 303, Sankagiri, Salem dt, Tamil Nadu,
India.
Affiliated periyar university, Salem.

DEPARTMENT OF MICROBIOLOGY
Subject: Food microbiology
High temperature
Topic : And
Low temperature

SUBJECT INCHARGE: SUBMITTED BY:

Dr. R. DINESHKUMAR, P. NIKOSHIYA CYPRUS,
Assistant professor, III-Bsc. Microbiology
Department of microbiology Department of microbiology
VIAAS, Sankagiri. VIAAS, Sankagiri
FISCAL YEAR 2020

2. Synopsis
High temperature

• Heat canning
• Pasteurisation
• Sterilization
Low temperature
• Chilling
• Refrigerator

3. • In food preservation, high temperature refers to
temperatures above 145°F (63°C) that are used to:

1. Kill pathogens and bacteria
2. Inactivate enzymes.
3. Extend shelf life
4. Improve food saftey.

•specific high-temperature ranges for food
preservation include:

1. Pasteurization: 145°F (63°C) to 155°F (68°C)
2. Sterilization: 212°F (100°C) to 250°F (121°C)
3. Canning: 212°F (100°C) to 240°F (115°C)
4. Cooking: 165°F (74°C) to 180°F (82°C)
HIGH
TEMPERATURE

4. •High temperatures are used in various food preservation
methods, including:
1. Heat canning
2. Retorting
3. Pasteurization
4. Sterilization
5. Cooking
6. Blanching
• These high temperatures help to:
1. Kill harmful bacteria and pathogens
2. Inactivate enzymes that cause spoilage
3. Extend shelf life
4. Improve food safety and quality.

5. 1.HEAT CANNING
•Heat canning, also known as thermal canning, is a food preservation
method that uses high temperatures to kill off bacteria, yeast, and
other microorganisms that can cause spoilage and foodborne illness.
• The process involves:
1. Packing food into airtight containers (cans or jars)
2. Heating the containers to a high temperature (usually
212°F/100°C) for a specified period (usually 10-60 minutes)
3. Cooling the containers to create a vacuum seal.
•Heat canning is commonly used for:
1. Fruits
2. Vegetables
3. Meats
4. Soups
5. SauceS
• There are two main types of heat canning:
1. Water Bath Canning
2. Pressure canning.

6. Canning

7. 2.Pasteurization
.
•Pasteurization is a heat treatment process that:
1. Kills pathogens (bacteria, viruses, and protozoa)
that can cause illness
2. Extends shelf life by reducing spoilage
microorganisms
3. Inactivates enzymes that can affect texture, flavor,
and color.

•The process involves heating a liquid or food to a
specific temperature (usually 145°F/63°C to
161°F/72°C) for a set period (usually 15 seconds to 30
minutes), followed by rapid cooling.

8. Pasteurization

9. Pasteurization:-
• Kills 99.9% of pathogens, making food safer for consumption
• Preserves nutrients and flavor- Increases shelf life- Is
commonly used for:
• Dairy products (milk, cheese, yogurt)
• Juices and beverages
• Eggs
• Honey
• Ready-to-eat foods.
There are different types of pasteurization, including:
•High Temperature Short Time (HTST)
•Low Temperature Long Time (LTLT)
•Ultra High Temperature (UHT)
• Extended Shelf Life (ESL)
Pasteurization is named after Louis Pasteur, who
developed the process in the 19th century.

10. 3.Sterilization
• Sterilization is a process that completely eliminates all forms
of microbial life, including:
1. Bacteria
2. Viruses
3. Fungi
4. Protozoa
5. Spores
•Sterilization is achieved through various methods, including:
1. Heat (autoclaving, retorting)
2. Chemicals (ethylene oxide, hydrogen peroxide)
3. Radiation (gamma, electron beam)
4. Filtration (using filters with pores smaller than
microorganisms)
5. Physical removal (cleaning, scrubbing)
•Sterilization ensures the complete elimination of
microorganisms, making it a critical process in various
industries where contamination control is essential.

11. Sterilization

12. In food preservation, low temperature
refers to a range of temperatures below
40°F (4°C) used to slow down the growth
of microorganisms, enzymes, and
chemical reactions that can cause spoilage
and degradation of food. The specific
temperature range for low-temperature
preservation is:-
•Chilling: 32°F (0°C) to 40°F (4°C)-
•Refrigeration: 40°F (4°C) to 38°F (3°C)
•Freezing : 0°F (-18°C) to -20°F (-29°C)-
•Quick freezing: -20°F (-29°C) to -30°F (-
34°C)-
•Deep freezing: -30°F (-34°C) to -40°F (-
40°C)
LOW
TEMPERATURE

13. Low temperatures:-
•Slow down bacterial growth and enzyme activity
• Inhibit chemical reactions that cause spoilage
•Preserve texture, color, and flavor
•Extend shelf life
Low-temperaturepreservationiscommonlyusedfor:
•Refrigerating perishable foods like meat, dairy, and fruits
• Freezing foods like meats, vegetables, and leftovers
• Storing frozen foods at very Low temperature

14. 1.Chilling
•Chilling refers to the process of cooling food or products to a
temperature between 32°F (0°C) and 40°F (4°C) to:
1. Slow down bacterial growth and enzyme activity
2. Inhibit chemical reactions that cause spoilage
3. Preserve texture, color, and flavor
4. Extend shelf life
• Chilling is commonly used for:
1. Short-term preservation of perishable foods like meat, dairy,
fruits, and vegetables
2. Storing food at a temperature that is lower than room
temperature but above freezing
3. Slowing down the growth of microorganisms, without freezing
the food

15. Chilling

16. 2.Refrigerator
•A refrigerator is an electrical appliance that uses refrigeration to
keep food and drinks at a cool temperature, typically between 39°F
(4°C) and 41°F (5°C). Its primary function is to:
1. Cool food to a temperature that slows down bacterial growth
and spoilage
2. Maintain a consistent temperature to preserve food quality and
safety
3. Store perishable items, such as meat, dairy, fruits, and
vegetables, for an extended period.
•There are various types of refrigerators, including:
1. Top-freezer
2. Bottom-freezer
3. Side-by-side
4. French door
5. Compact or mini-fridge
6. Commercial or industrial refrigerator.
• Refrigerators play a crucial role in maintaining food safety and quality
in households, restaurants, and industries.

17. Refrigerator

18. Thank you!