Transcription
झाल हेलो, हेलो एवरीवन. Today's topic will be microbiology, food, and factors affecting food spoilage. Food spoilage is a major problem. It can happen at any point in the course of food production, transport, storage, or preparation. Foods can be preserved by physical, chemical, and biological processes. Respiration can significantly reduce population, but only you can control the microbes. Chemical substances such as preservatives and organic chemicals can be used.
These are the factors that affect microbial growth in foods. They are intrinsic factors and extrinsic factors. Intrinsic factors are related to the food itself, such as water availability, physical structure of the food, nutrients, and the presence of natural microbial resistance. Extrinsic or environmental factors include temperature, relative humidity, gases present (that is, oxygen, carbon dioxide, and nitrogen), and the number of microbes present in the food.
It will be very interesting to know that food composition is a critical intrinsic factor influencing the microbial growth on food. Carbohydrate-containing foods, for example, favor fungal growth rather than bacterial growth on them, and spoilage will not result in major odors. In contrast, foods which contain high amounts of proteins, such as meat, butter, and eggs, favor bacterial growth, producing a variety of odors. You can think of the smell of rotting eggs, which is due to the presence of sulfur-containing compounds, and this process is called putrefaction.
Now let us discuss intrinsic factors to control the growth of microorganisms on food. pH is one of the modifications to pH. In neutral or alkaline foods, bacteria are dominant. Water availability is another factor. Water can be made unavailable by adding solutes such as sugar or salt to the food. This is called osmotic pressure.
The presence of natural antimicrobial substances is another factor. For example, in milk, lactoferrin is present, which binds iron and makes it unavailable for microbial growth. In spices like rosemary, there are phenolic compounds that have antimicrobial properties. Garlic contains allicin, which has antimicrobial properties. Green tea also has well-documented antimicrobial properties because of the polyphenol content. These compounds can kill bacteria, viruses, and fungi, and also have anticancer properties.
Other factors which control microbial growth in food are extrinsic factors, or environmental factors. The first point is temperature and humidity. These are important factors determining food spoilage. Relative humidity affects microbial growth. Temperatures, especially if not maintained at refrigerator temperatures, can lead to spoilage. Dry storage is preferred for many foods.
Most importantly, in which food storage is also important. This can be through wrapping in plastic film, which blocks oxygen. This results in the growth of facultative anaerobic microbes. In anaerobic conditions, the population is dominated by obligate anaerobes or facultative anaerobes.
Modified atmosphere packaging is another technology. Food near is a reference material, which lasts longer. Information will lead to oxygen monitoring. Wrap materials and vacuum technology make it possible to package foods with controlled atmosphere places. This can extend shelf life by a factor of two to five times when compared to the same products in air.
Oxygen also has an effect. How did it do to the formation of the superoxide radical? This superoxide radical is then transformed to highly toxic peroxide and oxygen. And this results in an antimicrobial effect. Some products which can be packaged using this MAP technology are grated cheese, pizza, and coffee.
So let's celebrate and discuss some questions on this topic. See answers in the video. Thank you for watching.