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Exposure of Baby food and the degree of contaminationFeatured science projectScience project video


This experiment was done to find out if leaving baby food out of the refrigerator after it has been opened will result in bacterial contamination.


Baby food will become more contaminated when it is left out for a longer period of time.

Scientific Terms

Microbes, bacteria, Escherichia coli, petri dish


Food poisoning

Food poisoning happens when we eat food that has gone bad. This food will have bacteria growing on it and it will smell bad. If we continue to eat it anyway, we will experience stomach pain, diarrhea and vomiting amongst other symptoms. Some types of bacteria commonly found in food are Escherichia coli, Listeria, Salmonella and Campylobacter.

Bacteria can be found in the environment all around us. Some of the bacteria is good for us but most of the bacteria found in food that has gone bad are harmful.

Food contamination

The presence of harmful substances like bacteria and chemicals in our food can lead to food poisoning. Carefully documented procedures are followed by food manufacturers to minimize the contamination of food by preparing and packing them in a sterilized environment. However, when we bring this food back to our homes and open them for consumption, the bacteria and other microbes in our surroundings come in contact with the food and lead to contamination. This is why canned and bottled food must be consumed as soon as possible, once opened.

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Complexity level:
Project cost ($):
Time required:
1 day to prepare, 3 days for experiment
Material availability:
Easily found
Safety concerns:

The bacteria should be destroyed before it is disposed of. Pour some bleach into the petri dish to kill all the bacteria before disposing in the trash.