0:04 [music] So the next topic under the food spoilage and preservation uh would be methods of food preservation. The objectives of this topic are students will be able to explain the reasons for food spoilage. Uh which is the physical, chemical and microbiological types of food spoilage and how different methods of preservation such as low temperature, low water activity levels can prevent the food spoilage. and to identify and apply specific methods like dehydration which is sun
0:50 drying, salting, fermentation and canning and freezing. Coming to the introduction. So the main principles of food preservation include shelf life, food safety and food quality. So with that being said, food preservation protects food from microbial development which differs from storing food in a covered container. Food stored properly is shielded from insects and flies which will keep them fresh for a little longer. However, it can't help extend the food shelf life.
1:35 So there are different kinds of food preservation methods which can serve its purpose. So in order to preserve the principles of food preservation like shelf life, food safety and food quality, food preservation methods comes into play. So coming to the objectives of food preservation. So the primary objective of food preservation is to inhibit the growth of microorganisms in food using methods like drying, freezing, canning and refrigeration. So these methods will help in retaining the nutritional value of food items,
2:20 will reduce the risk of foodborn diseases which is caused by pathogens and it will minimize the food wastage which is essential for food sustainability and security. It will also increase the convenience as they allow to easily have prepared food without needing to cook it. So food preservation method will help in preserving the quality of food, retaining the nutritional value of food and will help in reducing the risk of food born pathogens. So why is food preservation important? The main goal of food preservation is to keep food from spoilage before it is
3:08 consumed. There are additional reasons why food preservation is crucial. So it helps in preventing food from being wasted and it also keeps it out of wet waste. It enables to purchase products even during offse. offseason in the sense when uh there are certain food items like fruits and vegetables which are available seasonally only. So even in during uh the off seasons we can purchase these products if food preservation techniques are followed. So we have access to apples, cauliflower and peppers all year over the world globally. So it helps in prolonging the shelf life
3:55 of the product. helps in uh maintaining proper sanitation and hygiene. It helps in preserving the nutritional value of the product and it will also improve the quality of the product. These techniques will help the product from uh being ruined by microbial infections and enzyme activity. It helps in preventing microbial attack or enzyatic attack over the foods. It also lengthens the time that food may be stored. It enables to get perishables from different locations and it also helps in maintaining the nutritional content, color, texture and flavor of the food. So moving on to the
4:42 advantages of food preservation. Food preservation helps in minimizing food loss as the shelf life of food gets increased. It also ensures foods are seasonally available only for some part of the year but it is available for the entire year. So what happens when food is preserved? As far as health is concerned, preservation will help in protecting food from contamination and will help in also preserving the vital nutrients. uh sufficiency uh preserved foods will have a longerlasting uh effect and will be sufficient for usage or consumption and
5:30 affordability. Preservations of food means that the food will not be spoiled and it is not necessary that we are supposed to buy more of those commodities. It also ensures food safety by slowing bacterial growth. It enables the food to be stored, transported and distributed in bulk. It is useful for supplies to be so stored for an emergency and for long-term usage like any uh calamities that can occur or uh any drought or something that happens and we'll be able to provide the individuals or community with food when it is preserved well. But what are the disadvantages of food
6:16 preservation? There are certain disadvantages which we'll we'll be dealing with now. So uh the possibility of some of the nutrients present can be lost in certain type of food preservation processes or manufacturing. It also can change the taste, texture, color or flavor of the food when being preserved for a longer period of time. Some food preservation methods will require use of additional substances or chemicals. So food preservation methods like refrigeration or freezing is quite
7:01 expensive as they require a lot of energy being expended. Coming to the types of food preservation methods with examples being quoted. So the first one is drying. It is a timehonored method of food preservation. It reduces water content and helps in preventing bacteria from growing in the food substances. Food may be transported more readily since drying reduces weight. It can be stored by drying in the sun and wind. Many advanced techniques are needed and
7:48 it has emerged which involves professionals for usage of food dehydrators, shelf drying, spray drying, freeze drying and home ovens. Using this technique, meat and fruits can be stored extensively long. So this is one example of drying. So drying of chilies in the sun uh can actually help in preserving uh it from being attacked by microbial uh attacks or something. So coming to the benefits of drying method of food preservation. First thing is that it prevents the
8:34 spoilage of food. It extends the shelf life of the product. It retains nutrients lightweight and compact. It is a chemical-free method of preservation and it also enhances the flavor of the product. It is a versatile technique. The next method is smoking. So food is prepared by smoking. Subjecting it to smoke from burning wood which can prepare the food and ex enhance its flavor and preserve it. Most of the times meat and fish are smokeured
9:22 because the smoke has antibacterial and inhibitor properties. But it must be noted that smoking can increase the cancer risk. So this is a example that can be quoted for smoking method. So in this meat and uh fish uh products are uh being smoked or being prepared using the smoke that is generated out of the wood that is kept at the bottom of the surface. So this will enhance the flavor and uh preserve the product for a longer period of time. So chilling is the next method
10:07 of food preservation. The process includes it halts the activity of microbes and enzymes and can lead to decrease of spoilage and increase of shelf life. It will also preserve the texture and flavor of the food. It is especially useful for perishable foods such as diary, meat, seafood, and fresh produce by preserving food at temperatures between freezing point and 5° centigrade. So this is the temperature at which normally no bacteria or any other microorganisms can grow. Uh so moving uh back to the second unit
10:52 wherein we saw one of the factors which could influence the temperature of the uh food for it to be uh spoiled. So in that we saw a thermometer in which it uh actually represented the below 5° centigrade wherein there was a temperature that actually uh did not influence the growth of microorganisms. So any temperature below 5° centigrade will not have microorganisms growth or attack being caused. Whereas uh temperature between 5° centigrade to 63° centigrade we could actually see the growth of microbes being present and above 63° centigrade these microbes can
11:40 be destroyed by the presence of heat. So now coming to the chilling process since the foot can be maintained in 5° centigrade we will be able to halt the activity of microbes thoroughly. Unlike freezing, no ice crystals will be used during this process. So this will help in preserving the food quality as well. So this is an example of chilling. Food items can be stored in the refrigerator below 5° centigrade. It is also effective because it is a
12:27 natural preservative technique which can cut down on food nutrient degradation. Appropriate chilling and refrigeration is needed along with right temperature and there should not be crosscontamination so that the bacteria can be controlled and food can be ensured with freshness over an extended time period. So in order to prevent crosscontamination it is essential and mandatory that uh raw foods are stored separately and uh the cooked foods are supposed to be stored separately. Also the perishable products we are supposed to store them as per the
13:12 manufacturing date. The first uh uh stored product should be kept in the first uh place and then the other same product can be kept at the back and it could be used accordingly. Coming to the next technique which is the freezing. So it is one of the easiest most practical and quick method for preserving fresh vegetables. So food deterioration is decreased by freezing because at a very low temperature there's no growth or development of these dangerous germs which are nothing but bacteria, fungi, yeast, molds etc.
13:57 When they are ripest and contain most nutrients, fruits and vegetables are supposed to be cut and frozen at any time of the year. So foods are stored in the freezer uh and uh it will be helpful in destroying the growth of microorganisms. So what are the benefits of freezing as a food preservation technique? It helps in slowing down the spoilage. It increases the shelf life of the product. It preserves the nutrients. It preserves the flavor and texture as well.
14:43 And it lowers the waste. There's no use of chemicals and it saves time. It is a effective and fast method of food preservation. Coming to the next method which is salting and pickling. Sultting helps in preserving food by removing the moisture, preventing the bacterial growth and extending the shelf life of the product. It is commonly used for meats, fish, vegetables and grains either through dry salting or brining.
15:29 Pickling on the other hand will involve acidic solutions like vinegar or fermentation which will lower the pH level in order to inhibit harmful microbes while enhancing flavor. So as uh informed in the previous uh you topic which is nothing but the causes of food spoilage under which we dealt with the factors influencing food spoilage. So one of the factors was pH levels. So any pH level between 6.5 to 7.0 can cause the growth of microorganisms. So while pickling process is done addition of acidic solutions can actually destroy the growth of uh microbes.
16:16 So the method of salting. So what is the benefit that this method will bring? So it is popular for preserving vegetables, fruits and meat with fermented pickles offering probiotic benefits as well. Probiotic is nothing but a live microorganism that can be improved in our body uh because of the consumption of food sources such as fermented pickles uh curd etc. So this will help in improving the gut microfllora. So both the techniques can help in retaining the nutrients and will offer a distinct taste. [snorts] Additionally, lemon or lime
17:02 slices can also help in reducing the food waste by ensuring safe and effective long-term storage when it is properly sterilized. So the picture shows how pickling is done. So some of the examples of pickling includes uh carrot pickle or cucumber being pickled. Pickling is nothing but addition of vinegar or any acidic solutions to the food sources. So the next process is sugaring. This method will help in preserving the food by drawing out the moisture from the food and this will help in preventing the growth of bacteria and
17:48 fungi. So mostly sugaring is done on fruits, jams, jellies and even candies. So it is a natural preservative which will help in maintaining and protecting the texture while also enhancing the flavor of the product. So one of the examples wherein strawberry is being u preserved with the help of sugar is shown in the picture. So under sugaring there are various products that actually uses this technique. So this involves coating the food item with sugar as well as preserving the product with sugar syrup. So it helps in increasing the shelf life, retaining the nutrients and providing a safe food storage method
18:35 while it is also free from chemicals and sweetness. Next method is fermentation. So what is a fermentation? It is used for centuries in order to preserve food. So lacto fermentation will help in converting carbohydrates into lactic acid a natural preservative which will prevent the presence of harmful bacteria. So one classic example of fermentation is [clears throat] the production or preparation of curd. So lactose which is a carbohydrate from milk obtained from milk is converted into lactic acid when uh curd is stored
19:24 at room temperature overnight. So this will help in preventing the growth of harmful bacteria as well as improve the gut microfllora of the individuals while this food is consumed or this food product is consumed. So this process will help in extending the shelf life. It will also help in enhancing the nutritional value by increasing the vitamin and mineral bioavailability. So other examples of fermentation process include uh pickling of kimchi which is nothing but pickled cabbage um and sauerkraut uh all that. So this will help in
20:11 promoting the gut health through probiotics which will help in improving the flavor and texture as well as help in reducing the food waste. It will also support a healthy microbiome by boosting the immunity and aiding in digestion. Next method is vacuum packing. So this extends the food shelf life by removing oxygen preventing bacterial and fungal growth. This method will help in keeping foods fresh, flavorful and nutritious without preservatives. Common used uh method that is following the vacuum packing is meat, cheese, coffee and dried foods. So these are the
20:58 food products that actually uses vacuum packing in order to preserve their properties. So it helps in preventing oxidation and freezer burn. So vacuum sealing will help in reducing the food waste by uh long-term storage and it will also maintain the quality of the food product. It will also help in enhancing the hygiene because there cannot be a contamination or odor transfer happening because the package are sealed. It is an affordable and effective preservation method which will help in ensuring safety, convenience in storage, transportation and ease of food separation with proper sealing.
21:45 So this is an example of vacuum packing. It also extends the food shelf life by removing the oxygen preventing bacterial and fungal growth. This method will keep food fresh, flavorful and nutritious without preservatives. It helps in preventing the oxidation and freezer burn. Coming to the next technique which is canning. It preserves food by sealing it in attite containers and heating to kill bacteria, yeast and molds. So this will help in extending the shelf life of the food product for months or years while
22:31 maintaining the flavor and nutrients of the food product. Common for fruits, vegetables, meats and sauces. Canning helps in preventing the spoilage by eliminating oxygen and microbial growth. Methods include water bath canning for acidic foods and pressure canning for low acid foods. Proper sterilization and sealing has to be ensured while canning a food product. It becomes a reliable and effective method if uh these two techniques are thoroughly progressed. So this will help in having
23:16 a long-term food storage. So the foots will be stored in a tin based containers and it will be sealed. When while loosing the food we are supposed to just break the seal and consume the product as such or it has to be boiled according to the instructions being given or provided in the container. Coming to the next method which is irradiation. Food irradiation will use ionizing radiation in order to eliminate insects and microbes. This will enhance food safety and will also extend the shelf life of the product.
24:04 Similar to pasteurizing diary, [clears throat] this process will help in preserving fruits, vegetables and other perishable items which will make them safer for consumption over time. So what happens when irradiation technique is followed? Sprout inhibition can be given. So there will be sprouts being present in roots and tubers like potato, onion, garlic etc. while it is stored for a longer period of time. While uh following the procedure of irradiation, the sprout inhibition can be uh present and then quarantining of uh fruits and vegetables. Pathogen reduction can be done. Shelf life extension can be done and insect
24:51 disinfestation can also be followed with the help of irradiation technique. So irradiation will reduce the spoilage and contamination and this will help in ensuring that the food remains fresh and will also retain the quality for a longer period of time. This method is particularly beneficial for preventing food born illness and minimizing waste which will offer a reliable solution for maintaining food hygiene while supporting long-term storage and distribution without the need for chemical preservatives. Coming to the next method which is the
25:36 pasteurization. So pasteurization is a widely used food preservation method which involves the heating of a food product packaged and unpackaged foods such as milk, fruit juices etc. in temperatures below 100° centigrade. So this process will effectively destroy the harmful microorganisms by ensuring food safety and extending the shelf life. While using a gentle heat, pasteurization will maintain the nutritional value and flavor of food and will prevent the food from being spoiled. So commonly applied in diary and
26:22 beverage industries, this helps in reducing the risk of food born pathogens. So this method will provide a reliable chemical-free preservation quality and freshness for storage and consumption. So coming to the summary of this topic. So the most appropriate method for preserving food varies according to the food category storage facilities and desired longevity. Freezing will work well for meats and vegetables while canning is excellent for fruits, sauces and soups.
27:09 Drying works for herbs, grains etc. Whereas perishables should be preserved using wacom packing. Both pickling and fermentation will increase the taste as well as the gut bacteria health. Sugaring and salting works well for fruits and meat. Appropriate technique aids in safety, quality and effectiveness in long-term storage of the preserved food. So common food preservation methods include thermal processing, low temperature storage which is nothing but the freezing refrigerator techniques etc. drying vin dehydration or uh sun
27:54 drying or wind drying method was dealt with and chemical preservatives like addition of acidic solutions or vinegar to products uh so that it will be preserving its food quality. fermentation process which is a biological method of preservation and modern methods like vacuum packing, canning etc. was actually seen in this topic. Irradiation is also one of the methods wherein uh it can help in preventing the formation of sprouts in roots and tubers. It will help in uh reducing the bacterial growth. It will help in preserving the food quality. uh extend the shelf life of the product and
28:40 will help in uh reducing the in insect disinfestation. [music] >> [music]
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