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Showing posts from August, 2020

What Is Food Fermentation? (Definition And Processes Of Fermentation)

Fermented foods may be defined as those foods, which have been subjected to the actions of microorganisms or enzymes so that desirable biochemical changes cause significant modification to the food.
By fermentation, food may be made more digestible, nutritious and safer or have better flavour.
The class of fermented food produced in different regions of the world reflect the diet of that region and also the available raw material.

What are the reasons for fermenting foods?(1) Improvement of digestibility: Digestibility, which is measured through different parameters, is generally improved through fermentation.
The enzymes of the fermenting microorganism hydrolyze the complex constituents of the starting material.
(2) Fermentation almost invariably adds flavour to the food: In some cases, the flavour of a partial product is improved directly.
In some other cases, they can be used to make tasty food from different plant product.
(3) To improve the appearance of food: food like Angkak (oriented…

Causes Of Spoilage On Heat Processed and Canned Foods

Canned foods are classified as spoiled when for any reasons the food has undergone a deleterious change or the condition of the unopened container renders such changes possible.

Spoilage may arise from a variety of causes which include the activity of microorganisms, chemical reaction between the can contents and the container, faulty technique in canning practice, rough handling and poor storage condition.

Spoiled cans may present a perfectly normal appearance or they may show obvious abnormalities such as varying degrees of distortion.

In certain instances where distortion of the can has arisen from physical causes, the contents may be quite wholesome, how ever such cans are considered to be spoiled since they are visually indistinguishable from cans which have spoiled content as a result of microbial activity.


Appearance of Unopened CansThe terms flat, flipper, springer, soft swell and hard sell are some of the terms associated with spoiled unopened canned foods.

Here's a brief expl…

List Of Food Borne Diseases And Illnesses (Complete List)

Food borne diseases are illnesses caused by the consumption of food, drink and water infected by microorganisms.




List and examples of food borne diseasesStaphylococcal infection Salmonella sp. infectionViral gastroenteritisEscherichia coli infectionCyclosporiasisCryptosporidiosisCampylobacteriosisVibrio parachaemolyticus Clostridium perfringens infectionClostridium botulinum infection Bacillus cereus infection ListeriosisEscherichia giardiasisEnteropathogenic Escherichia coliSalmonella wien infection Salmonella typhimurium infection Salmonella brandenburg infection Salmonella senftenburg infection Salmonella virchow infection Salmonella paratyphiasis Salmonella eastboune infection
Food hygiene are the practices and innovations aimed at preventing the contamination of food and water with pathogenic macro organisms, protozoan helminthes or their toxic metabolites through controlling the contaminating agencies of processing machinery, food handlers, animals, pests and the immediate surroun…

Autoclave (Definition, Types, Parts And Uses)

An autoclave is a routine equipment for sterilization of materials in the food microbiology laboratory, food industries and hospitals.


In a typical modern autoclave, steam is introduced under pressure into a chamber containing the material to be sterilized.




The pressure is generally adjusted to 103.4 kPa or 15 lb/in² so that temperature of 121°C is reached.


Bacteria are readily killed by moist heat (saturated steam) than by dry heat.


Sterilization kills bacteria by denaturing the protein.


A condition for sterilization is the use of steam at 121°C for 15 minutes at 15 lb/in² or 103.4 kPa.


Autoclaves are also very useful in the sterilization of microbiological cultural media.



Parts of an Autoclave
Safety valvesPressure gaugeManual operating valvesDoor handlesSteamBaffleChamberSteam supplyThermostatic trapsPressure regulatorThermometer.

Types of Autoclave
Industrial autoclaveBenchtop autoclaveComposite autoclaveTabletop autoclaveParker autoclave

Uses of autoclaveAn autoclave is used to sterilize me…

How to Use A Microscope (Step by Step Guide)

What is a Microscope?A microscope is a tool used for scientific research studies for viewing and magnifying microorganisms.

There is a strong need for food microbiology professionals to understand the features of microbiological examination and standards of food.

In addition, they should be familiar and able to use the basic tools used in food microbiology such as the microscope.

The study of food microbiology requires the use of some basic tools.

The use of some of these tools call for the acquisition of specific skills.

The development of microbiological skills go hand in hand with knowledge of precautionary measures needed to shield the microbiologists and laboratory staffs from dangers posed by pathogenic organisms.

Precautionary measures are strictly followed when working with medical and microbiological research study tools.

These measures are usually given as general instructions and codes of practice.


MicroscopeA microscope is a basic tool used in the study of microorganisms from vari…

Routine And Special Microbiological Testing Of Foods

A microbiological analysis should be an indispensable part of any food manufacturing or food preparation operation.

Surveillance on a continuous basis on the microbiological status of raw materials for food processing, ingredients, water supply, equipment surfaces, containers and finished products supplemented with spot checks along the production line is a sine-qua-non for good manufacturing practice.



Additionally, new products are tested for wholesomeness before marketing.

The extent of microbiological analysis will depend upon the nature of the product, the storage temperature and duration of storage and other detailed information that may be required.

The need for the provision of certain basic equipment and the need to replace consumable materials regularly make microbiological monitoring expensive.

The time for the development of colonies that introduces delays in the posting of result is a major limiting factor in microbiological quality control.

Some tests such as the microscopic co…

Laboratory Media and Biochemical Tests In food and Water

A culture medium is a composite of nutrients and other factors in liquid and solid form on which microorganisms are grown in laboratories.

Some organisms are fastidious in their demand for specific nutrients and growth factors.



Culture media must mimic as closely as possible, the content of components in natural growing environment of the organisms to be grown.

laboratory media invariably should contain the following five components:

1. Water

2. A nitrogenous source such as proteins, amino acids and other nitrogen containing organic compounds.

3. An energy source such as carbohydrate, protein and fat.

4. Accessory growth factors

5. Minerals

Some organisms are fastidious in the requirement for specific nitrogen, energy and accessory growth factors while others are less demanding.


Media for Growth and Isolation of MicroorganismsFormulation of culture medium depends on the group of organisms being studied and also on the overall purpose of the study.

The purpose may be to encourage good growth of t…

Microbiological Experiment Of Food And Water Samples

Principles: The original source of any drinking or that used for preparing food may be rich in aquatic microbes some of which would be dangerous if they enter the human body.

The analysis of such water becomes apparent for avoidance of subsequent health problem that may arise from their usage.

AIM: test for the bacteriological safety of three different sources of water supply - tap water, a river and irrigation ditch.


Materials Required 3 sterile McCartney bottles9 sterile petri dishes3 sterile 1ml graduate pipettes9 tubes of sterile Nutrient agar at 48°C, each 9ml.3 tubes of sterile water each containing 9ml water samples.

Procedure:(i) Take 3 labelled samples of the water collected (A,B, and C)

(ii) Shake sample A gently and transfer 1ml into a sterile plate and 1ml in another plate.
Label plates properly.

(iii) Add 1ml of A to 9ml sterile water and mix properly to give 10-² dilution.
Transfer 1ml of the 10-² dilution to a sterile petri dish, label appropriately.

(iv) Repeat steps (II) and (…

Food Microbiology (A Study Of Microorganisms)

Microbiology of food is a comprehensive topic and is concerned not only with spoilage but also with beneficial changes brought about by microorganisms.

Microorganisms may be classified as other forms of life, into two main groups, animals and plants.

In the animal kingdom, we have:

(i) Single-celled animals (protozoa)
(ii) multicellular animals (this includes all other forms except protozoa).

The plant kingdom or Thallophytes which are characterized by no true roots, systems, or leaves.

Members of this group are: algae (contains chlorophyll) and fungi (no chlorophyll).

This group contains mushrooms, molds, yeasts, and bacteria.

Food is a true ecosystem, and a high-nutrient environment capable of sustaining many microbial lives.

These microorganisms can being about a very positive transformation of the food into a highly valued product while some others can completely render the food useless.

The microbiologists and food processors endeavour to explore these positive and negative characters of m…

List Of Minerals In Food (Complete List)

Minerals do occur in foods in both organic and inorganic compounds.

The major inorganic compounds or inorganic minerals in food are the:
CarbonatesChloridesSulfates and phosphates of sodiumCalciumPotassiumMagnesium.
The following food minerals are nutrients essential for human nutrition:
Calcium ChlorineCobaltCopperFluorineIodineIron MagnesiumManganesePhosphorusSodium and Sulfur.
Minerals that compose the ash occur in different proportions in different foods.

Calcium for instance occurs in relatively high concentrations in diary and diary a containing products, cereals, nuts, fish, eggs, and some vegetables (James, 1996).

In determination of mineral elements in food, the ash is first isolated and the resultant ash used in the determination of the individual metals.



Various methods are available for the determination and estimation of mineral elements in food.

These methods are titrametric method, ion-exchange chromatography, emission spectroscopy, flame photometry, atomic absorption spectrosco…

Classification Of Carbohydrates (Including Carbohydrate Test)

Carbohydrates are generally the most abundant singular food component in nature and are widely distributed.

Carbohydrates are classified into:(i) Oligosaccharides which occur when the hydroxyl group of one monosaccharide is condensed with the reducing end of another monossccharide (two sugars when joined in this way produces a disaccharide).

If however, a linear array of three to eight monosaccharide join in this manner an oligosaccharide is generated.

(ii) Polysaccharides which are grouped into two - the structural polysaccharides (which include: cellulose, hemicellulose, lignin).




They constitute the rigid, mechanical structures in plants, and nutrient polysaccharides (include: starch, glycogen) which can easily be digested.

Essentially, methods of carbohydrate analysis are: By difference Titration, Colorimetry, Refractometry, Polarimetry, Enzymes methods, and High performance liquid chromatography (H PLC).

By Difference: In this method carbohydrate content is obtained by calculation havin…