Food spoilage is the result of chemical, physical, biochemical, mechanical, organoleptical, microbiological, and other factors.

Food spoilage is the result of chemical, physical, biochemical, mechanical, organoleptical, microbiological, and other factors. Excellent books related to food spoilage discussions include Modern Food Microbiology by Jay and colleagues, Microbiology of Fruits and Vegetables by Sapers and colleagues, Microbiological Control for Foods and Agricultural Products by Bourgeois and colleagues, Food Microbiology: An Introduction by Montville and Mathews, Food Microbiology: Fundamentals and Frontiers by Doyle and Beuchat, and many others.

1. Spoilage of Food and Factors Governing the Spoilage Mahatma Jyotiba Phule Rohilkhand University Submitted by: Subhana Noor Submitted to: Ms Ayushi Sharma M.Sc Microbiology IIIrd Semester

2. Food spoilage may be defined as any change that renders food unfit for human  consumption. These changes may be caused by various factors, including contamination by microorganisms, infestation by insects, or  degradation  by endogenous enzymes (those present naturally in the food ).  The chemical reactions catalyzed by the enzymes result in the degradation of food quality, such as the development of off- flavours , the deterioration of texture, and the loss of nutrients . What is F ood Spoilage?

3. Food spoilage can be caused by the following: Rodents Insects Physical injury due to bruising or freezing (texture changes) Tissue enzyme activity (flavor changes) Non-enzymatic chemical changes Micro-organisms Food spoilage is evidence as changes in: Appearance Color , changes. Pockets of gas swelling, visible mold growth Texture Odor Flavor Slime production

4. Factors affecting Food spoilage Physical Chemical Microbial Moisture content Temperature Molds Yeast Bacteria Oxidation Proteolysis Putrification

5. Physical Factors Physical food degradation is the term used to describe physically changed or unstable food. Moisture content :- The cause of degradation of food products is the change in their water content. It occur in the form of water loss, water gain, or migration of water. Moisture migrate in food is directly related to the water activity of food item. 2. Temperature:- A low temperature may also adverse impact on food products that are vulnerable to freeze damage. Food goods become damaged when their cells break when partially frozen at lower temperatures. Higher temperatures accelerate enzymatic reactions, leading to faster degradation of food quality, flavor, and nutritional value . High temperatures can cause proteins in food to denature

6. Microbial Factor Bacteria Yeast Mold These organisms secrete gas and vast amounts of extra-polysaccharides resulting in slime on meat and ropy spoilage in some food products . Populations of between 10 7  and 10 8  cells per gram produce off-odours in meats and some vegetables. The four main yeast species that cause yeast spoilage are  Zygosaccharomyces , Debaryomyces hansenii , Brettanomyces ,  and  Candida . spoils fruits, some vegetables, honey, dry fruits, jams, and soya sauce and dairy products.  Some molds that cause food spoilage are Zygomycetes , a primitive fungus that proliferates on fruits and vegetables rich in fruits like strawberries and potatoes. Some of them also grow in bread.

7. Chemical Factor :- Chemical and biochemical reactions occur in foods and lead to spoilage and changes are: • microbial growth and metabolism which results in pH changes, • toxic compounds, and • the oxidation of lipids and pigments in fat Oxidation:- Amino acids convert into organic acid and ammonia in presence of oxygen. This Is occur in refrigerated fresh meat and fish. The term ‘ rancidifcation ’ is used to indicate lipids oxidation through which unsaturated fats (lipids) undergo reaction with oxygen. This result in food change in color, off-flavor, and toxic substances formation. Proteolysis :- A ubiquitous and irreversible posttranslational modification, involves limited and highly specific hydrolysis of peptide and iso -peptide bonds of a protein is proteolysis. The entire phenomena require the presence of protease enzymes. The following reaction presents proteolysis mechanism: Proteins proteinase −→ Peptides peptidase −→ Amino Acids Many of these peptides have stiff taste which can be bitter or sweet.

8. Putrefaction :- As a result of a sequence of anaerobic processes, amino acids divert to a mixture of amines, organic acids, and sulphur compounds with strong odours like mercaptans and hydrogen sulphide. Due to the necessity of bacteria throughout the entire process, this is a biological phenomenon. Together with amino acids, indole, phenols, and ammonia are also present in protein putrefaction, and these chemicals are unpleasant to smell. With foods high in protein that are heated over 15°C, putrefaction is extremely common.