Microbial spoilage of canned foods and its preservation (Canning)

Food preservation is the process of preventing food spoilage and extending its shelf life. Food spoilage is the deterioration of food quality and safety due to physical, chemical, and microbial factors. Food preservation methods aim to inhibit or eliminate these factors by applying various techniques such as drying, freezing, salting, smoking, fermenting, pickling, and canning.

Canning is one of the most widely used food preservation methods in the world. It involves processing and sealing food in airtight containers that can withstand high temperatures and pressures. Canning was invented in the early 19th century by Nicolas Appert, a French confectioner who experimented with preserving food in glass bottles. He discovered that heating food in sealed containers could kill harmful microorganisms and prevent spoilage. He also found that adding salt, sugar, vinegar, or spices could enhance the flavor and shelf life of canned food.

Canning has many advantages as a food preservation method. It can preserve almost any type of food, such as fruits, vegetables, meats, seafood, dairy products, soups, sauces, jams, and juices. It can retain the nutritional value, color, texture, and taste of food for a long time. It can also reduce food waste and transportation costs by making food available all year round and in remote areas. Canning is also a safe and convenient way of storing and consuming food, as it does not require refrigeration or special preparation before eating.

However, canning also has some disadvantages and challenges. It requires specialized equipment and skills to ensure proper processing and sealing of containers. It also consumes a lot of energy and water during the heating and cooling stages. Canning may also affect the quality of food by causing changes in texture, flavor, color, and nutrient content due to high temperatures and pressures. Moreover, canning may pose health risks if not done correctly or if the containers are damaged or contaminated. Some of the common problems associated with canned food are botulism, flat sour spoilage, thermophilic anaerobic spoilage, sulfide spoilage, and mold spoilage.

Therefore, canning is a complex and delicate process that requires careful attention to details such as the type of food, the pH level, the container material and size, the filling method, the exhausting method, the sealing method, the processing time and temperature, the cooling method, the labeling method, and the storage conditions. In this article, we will discuss these aspects in detail and explain how canning can prevent microbial spoilage of canned food. We will also classify canned food based on pH and describe the causes and types of microbial spoilage that may occur in canned food. Finally, we will suggest some alternative or complementary preservation methods that can enhance the safety and quality of canned food.