Microbial Food Spoilage- Types of microorganisms with examples

Food spoilage is the deterioration of the quality, safety, and acceptability of food due to the growth and activity of microorganisms. Microorganisms are microscopic living organisms that can be found everywhere in nature. They include bacteria, fungi, protozoa, algae, viruses, and prions. Some microorganisms are beneficial for food production, such as those involved in fermentation, while others are harmful and cause food spoilage.

Food spoilage can result in various changes in the appearance, texture, flavor, odor, and nutritional value of food. Some of these changes may be visible to the naked eye, such as mold growth, discoloration, or slime formation, while others may not be easily detected, such as toxin production or pH reduction. Food spoilage can also pose a health risk to consumers if they ingest contaminated food that contains pathogenic microorganisms or their toxins.

The extent and rate of food spoilage depend on several factors, such as the type and number of microorganisms present in the food, the intrinsic and extrinsic properties of the food, and the storage and handling conditions of the food. Intrinsic properties are those that are inherent to the food itself, such as water activity, pH, nutrient content, and natural antimicrobial compounds. Extrinsic properties are those that are related to the environment surrounding the food, such as temperature, humidity, oxygen availability, and light exposure.

Different types of microorganisms have different preferences and requirements for growth and survival in food. Therefore, different types of food may be susceptible to different types of spoilage microorganisms. In general, foods that have high water activity (aw), neutral or slightly acidic pH (6-7), and high nutrient content (such as proteins and carbohydrates) are more prone to bacterial spoilage. Foods that have low water activity (aw), acidic or alkaline pH (2-8.5), and low nutrient content (such as fats and oils) are more prone to fungal spoilage. Foods that have intermediate water activity (aw), acidic pH (3-5), and high sugar or salt content (such as jams or pickles) are more prone to yeast spoilage.

In this article, we will discuss the different types of microorganisms that cause food spoilage and provide some examples of foods that they affect. We will also briefly mention some methods to prevent or control food spoilage by microorganisms.