0:04 [music] >> Hello all. The next topic of the unit will be food spoilage, its causes, and prevention. So, the objectives of the topic will be the students can identify the causes and types of food spoilage. And they will also be able to discuss the main causes and prevention of food spoilage. So, the introduction of the topic food is an essential part of our daily life, and it plays a vital role in maintaining our health and well-being.
0:51 However, food can easily spoil, which can lead to growth of harmful microorganisms and loss of its nutritional value. The process of food spoilage will occur in various grounds, which is crucial to understand the causes and prevention measures in order to ensure the safety of the food that we consume. So, what are the causes of food spoilage? There are numerous causes that can affect the quality of food. So, food spoilage will occur when microorganisms like bacteria, yeast, and mold can grow
1:37 and multiply on food surfaces. So these organisms growth is influenced by numerous factors, which includes temperature, moisture, pH, and oxygen levels present in food. So, food spoilage, the causes and effect is actually classified as physical, microbial, and chemical. So, the physical process includes the presence of moisture content and the temperature. Microbial process includes different types of microorganisms like yeast, mold, and bacteria growth in the food.
2:22 Chemical processes includes the uh enzymatic and uh chemical reactions like oxidation, proteolysis putrefaction pectin hydrolysis, Maillard reaction, and hydrolytic rancidity. So, coming to the factors that can influence the food spoilage. The first factor is temperature. It is a crucial factor which affects the growth of microorganisms on food. So, when food is stored temperatures between 40 and 140° F, it will create an environment which is conducive for the growth of bacteria or
3:07 microorganisms. So, this can make the food unsafe for consumption. So, the range of bacteria is given in this picture. So, the red color that is present in the picture indicates the temperature danger zone which ranges from 5 to approximately 63° C or 40 to 140° F. Anything above 63° C and anything below 5° C is safe for consumption. So, below 5° C is called as the cold food temperature zone and above 63 or 60° C is called as the hot food zone.
3:55 So, in the 60 above 63° C or 60° C, the uh bacteria is destroyed. Likewise, [snorts] in the temperature that is below 5° C, there's no possibility of the microorganisms or bacteria to grow. So, the next factor that can influence food spoilage is moisture. Presence of moisture is a critical factor which will promote the growth of microorganisms. High moisture levels in food can lead to growth of mold. While low moisture levels can lead to the growth of bacteria. So, it is crucial for the food to be stored in dry
4:42 and cool environment in order to prevent spoilage. So, what happens in mangoes in case of uh low moisture content present, it can lead to respiration and respiration will remove the water content present in it and it can lead to microorganism production. The next one is the pH. Presence of pH in food can also influence the quality of food. So, the pH level of food will measure the acidity and alkalinity of food. Microorganisms will thrive in different pH levels and it requires specific pH
5:30 levels to grow. So, bacteria which can cause spoilage of food products will grow in temperature around or sorry, pH around 6.0 to 7.5. So, uh like temperature as I told you all, 40 to 140 Fahrenheit can influence the food spoilage mechanism. The same way pH of around 6.0 to 7.5 is the medium for the microorganisms to grow. So, we are supposed to monitor the pH level of food in order to prevent it from being spoiled. So, different food varieties and their pH levels are given in this picture.
6:16 So, pH includes acidic medium, neutral medium, and alkaline medium. So, any food around 6.0 to 7.5 is unsafe for consumption as it is or it becomes the medium for the microorganisms to grow. Coming to the oxygen, which is the next factor that influences the food spoilage mechanism. So, it is a factor which affects the growth of microorganisms on food. So, these microorganisms actually require oxygen to grow while other microorganisms will grow in the absence of oxygen, which can be classified as aerobic and anaerobic conditions. So,
7:05 in order to prevent the growth of microorganisms, it is essential to store food in either aerobic or anaerobic condition according to their priority. So, oxygen can actually cause the deterioration of food as present in the given picture. Coming to the types of food spoilage, >> wherein food is actually spoiled because of the growth of microorganisms like bacteria, yeast, and mold. So, this type of spoilage will actually
7:52 influence the texture, taste, and appearance of food. So, an example can include the spoilage of meat, which can lead to slimy texture of meat and off-flavors present in the food. So, food deterioration, as I informed in the previous slides, so can be actually influenced by loss of moisture, inappropriate temperature, presence of microorganisms, time, uh physical uh physical uh processes like temperature or moisture content, and then um also the uh presence of uh microorganisms and environmental factors like industrial
8:37 exposures, chemical being present in the food etc. Then comes chemical spoilage, wherein chemical reactions like oxidation or putrefaction can lead to changes in color, texture, taste, and smell of food. So, this type of spoilage can occur due to exposure to light, oxygen, or other chemicals. So, an example of chemical spoilage includes exposure of fruit to air, which can lead to brownish spots because of oxidation. Then comes physical spoilage, wherein food is damaged due to external factors such as pressure,
9:24 temperature, or moisture. So, these factors can actually lead to changes in texture, color, and smell or appearance of food. So, one such example is the ice crystals when being thawed actually loses its texture and can lead to inappropriate food texture. Coming to the prevention techniques. So, food spoilage can be prevented by various techniques. So, we will be dealing with the different techniques that are involved in the prevention of food spoilage. Preventing food spoilage is crucial in order to
10:12 ensure the safety and quality of the food that we consume. So, the common prevention measures includes proper storage. Proper storage will help in preventing the growth of microorganisms on food. So, storage includes the storing of food at right temperature, right pH level in order to prevent the growth of microorganisms. So, an example of proper storage that could be quoted is meat should be stored in refrigerator at a temperature of 40° F or below in order to prevent the growth of bacteria. So,
10:57 various [clears throat] food prevention spoilage prevention methods can be seen. First one of that is practicing good hygiene, cooking food properly in proper hygiene and sanitation conditions, and drinking safe water, storing food safely, and cautious of food storage. So, these methods or these techniques can actually prevent the food from being spoiled or deteriorated. The next prevention method is hygiene. Hygiene is crucial in preventing food
11:42 spoilage. So, it is essential or mandatory to wash hands, utensils, and surfaces in order to prevent the spread of microorganisms. So, any point of contact places for the food, such as hands, utensils, and the place where the food is being cooked. It is essential for us to clean them thoroughly so that microorganisms cannot grow in the places or the point of contact of food. So, it is also essential to crucially separate raw and cooked food in order to prevent cross-contamination because raw foods normally contain a lot of
12:28 microorganisms in them than cooked foods. Preservation techniques can also prevent the presence of microorganisms in the food. So, the various preservation techniques that include canning, freezing, drying, which can actually prevent food spoilage by reducing the growth of microorganisms. So, canning involves heating food to a high temperature of which microorganisms can be killed. While freezing or drying will remove the moisture content from food and prevent the growth of microorganisms. Then, adding preservatives. Preservatives are nothing but food substances which can reduce or prevent
13:14 the growth of microorganisms. >> [snorts] >> So, these preservatives include salt, sugar, and vinegar, which can actually help in preventing the food spoilage by reducing or preventing the growth of microorganisms. So, we are supposed to use these preservatives by following the recommended guidelines in order to prevent adverse health effects or manage the health quality of adults. So, good as I told you all, the prevention techniques include cooking food properly, storing of raw food separately from cooked foods, and then good hygiene or
13:59 appropriate cleanliness has to be followed while preparing food, and then safe water is supposed to be ensured. Storing the food safely is also to be ensured. Then food storage, like the temperature of the food, the pH level of the food, all that has to be checked before consuming food. So, the key takeaways of the unit include we saw about the causes of food spoilage or the factors that influence food spoilage. So, the main factors that influence food spoilage included temperature, which is around 5° to 63° C, below which it is called as the cold food zone, and above which it is called
14:45 as the hot food zone, wherein bacteria is destroyed. And in cold food zone, bacteria will not be able to grow. Likewise, pH is another which influence the food spoilage, of which about 6.0 to 7.5 is the ideal medium for the bacteria or microorganisms to grow, and the foods are supposed to be maintained below 6.0 and above 7.5 in order to make it safe for consumption. Coming to oxygen, which is another factor that influence food spoilage. So, aerobic and anaerobic conditions will help in influencing the food for being safe for consumption. Then,
15:32 the other factor included the presence of moisture content, wherein high moisture content can actually lead to presence of mold in the food, and low moisture content can lead to the presence of bacteria in the food. Coming to the types of food spoilage, so types of food spoilage included the physical, chemical, and microbial spoilage methods, wherein physical spoilage included the temperature and pressure being involved in the uh changes of texture, appearance, and taste or smell of food. Likewise, chemical spoilage included the uh methods such as oxidation, putrefaction, etc., which can lead to uh the food deterioration. That is, it
16:18 becomes unsafe for uh unsafe for consumption because of loss of nutritional value and uh presence of um microorganisms. Likewise, microbial growth because of uh not storing the food in the right temperature, right pH, or uh presence or absence of oxygen can actually lead to growth of microorganisms in food, which can lead to uh food being unsafe for consumption. And the last thing that we saw in this uh topic was prevention strategies, which ensured good hygiene practices, storing food in uh safe places, and then drinking safe
17:05 water uh keeping raw food and cooked food separately, and maintaining right temperature and pH in order to prevent the growth of microorganisms. >> the growth of microorganisms.
