What are the methods that could be used at home to prevent the following from spoilage : a. Grain b. fruits c. vegetables d. milk
Answers
Answer:
Food spoilage can be defined as “any sensory change (tactile, visual, olfactory or flavour)” which the consumer
considers to be unacceptable. Spoilage may occur at any stage along food chain. Spoilage may arise from insect
damage, physical damage, indigenous enzyme activity in the animal or plant tissue or by microbial infections. Most
natural foods have a limited life. Perishable foods such as fish, meat and bread have a short life span. Other food
can be kept for a considerably longer time but decomposes eventually. Enzymes can bring about destruction of
polymers in some foods while chemical reactions such as oxidation and rancidity decompose others but the main
single cause of food spoilage is invasion by microorganisms such as moulds, yeast and bacteria. In case of mould
spoilage a furry growth covers the food and it becomes soft and often smells bad. Bacterial contamination is more
dangerous because very often food does not look bad even though severely infected, it may appear quite normal. The
presence of highly dangerous toxins and bacterial spores is often not detected until after an outbreak of food
poisoning, laboratory examination uncovers the infecting agent.
Key words: Food spoilage, Enzymes, Bacterial contamination, Food poisoning, Perishable foods.
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INTRODUCTION
Food spoilage is a metabolic process that causes foods to be undesirable or unacceptable for human consumption
due to changes in sensory characteristics. Spoiled foods may be safe to eat, i.e. they may not cause illness because
there are no pathogens or a toxin present, but changes in texture, smell, taste, or appearance cause them to be
rejected. Some ecologists have suggested these noxious smells are produced by microbes to repulse large animals,
thereby keeping the food resource for themselves [1]. Food loss, from farm to fork, causes considerable
environmental and economic effects. The USDA Economic Research Service estimated that more than ninety-six
billion pounds of food in the U.S. were lost by retailers, foodservice and consumers in 1995. Fresh produce and fluid
milk each accounted for nearly 20% of this loss while lower percentages were accounted for by grain piroducts
(15.2%), caloric sweeteners (12.4%), processed fruits and vegetables (8.6%), meat, poultry and fish (8.5%), and fat
and oils (7.1%) [2]. Some of this food would have been considered still edible but was discarded because it was
perishable, past its sell-by date, or in excess of needs. There are also environmental and resource costs associated
with food spoilage and loss. If 20% of a crop is lost, then 20% of the fertilizer and irrigation water used to grow that
crop was also lost. Shelf life of a food is the time during which it remains stable and retains its desired qualities.
The wide array of available dairy foods challenges the microbiologist, engineer, and technologist to find the best
ways to prevent the entry of microorganisms, destroy those that do get in along with their enzymes, and prevent the
growth and activities of those that escape processing treatments. Troublesome spoilage microorganisms include
aerobic psychrotrophic Gram-negative bacteria, yeasts, molds, heterofermentative lactobacilli, and spore-forming
bacteria. Psychrotrophic bacteria can produce large amounts of extracellular hydrolytic enzymes, and the extent of
recontamination of pasteurized fluid milk products with these bacteria is a major determinant of their shelf life.
Fungal spoilage of dairy foods is manifested by the presence of a wide variety of metabolic by-products, causing
off-odors and flavors, in addition to visible changes in color or texture.
Seema Rawat Asian J. Plant Sci. Res., 2015, 5(4):47-56
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48
Pelagia Research Library
Coliforms, yeasts, heterofermentative lactic acid bacteria, and spore-forming bacteria can all cause gassing defects
in cheeses. The rate of spoilage of many dairy foods is slowed by the application of one or more of the following
treatments: reducing the pH by fermenting the lactose to lactic acid; adding acids or other approved preservatives;
introducing desirable microflora that restricts the growth of undesirable microorganisms; adding sugar or salt to
reduce the water activity (aw); removing water; packaging to limit available oxygen; and freezing. The type of
spoilage microorganisms differs widely among dairy foods because of the selective effects of practices followed in
production, formulation, processing, packaging, storage, distribution, and handling
Answer:
a. Grain - Drying
b. Fruits - Cooling
c. Vegetables - Cooling
d. Milk - Pasteurization
I hope this will hepled u