Food spoilage by Microbes

14. Food spoilage by Microbes 10 Most Dynamic Business Leaders in Healthcare and Lifescience Industry 2022

Food spoiling is the process by which food deteriorates to the point where it is no longer edible to humans or loses its edibility quality. Among the many factors microorganism is one also responsible for food spoilage. A microorganism/ microbes are a microscopic organism made up of a single cell (unicellular), cell clusters, or multicellular highly complex organisms.

Food spoilage and its impact

Food losses are a critical issue. It is of concern to reduce hunger, increase income, and enhance food security in the world’s poorest countries. Food loss has impact on poor people’s food security, food quality and safety, economic development, and the environment. The precise causes of food losses differ. Worldwide and are very dependent on the individual variables and local scenarios in a certain area. Crop production decisions and patterns, internal infrastructure, and other factors impact the food losses. Food loss has to be minimum in any country. Food loss indicates the wastage of resources. The post-harvest fruit and vegetable loss is high in the world.

Food spoilage by microbes

Bacteria are the most common cause of food spoilage because they can grow in a wide range of settings; nonetheless, bacteria are beneficial for the fermentation of pickles, milk products, and some fermented vegetable products. Bacteria cannot thrive in water with an activity level of less than 0.91 and require a neutral pH (6.5-7) to induce food spoiling (e.g. milk, meat, green vegetables, fruits, etc.)

Some bacteria can create spores, making them highly heat resistant, and others can produce heat-resistant poisons. Intake of such damaged food may cause food borne disease. Gram-positive bacteria that cause food spoiling include Staphylococcus aureus, Bacillus spp, Clostridium spp, Lactic acid bacteria (LAB), Leuconostoc spp, Streptococcus spp, Brochothrix spp, Weissella spp, Mycobacterium bovis, and others.

Gram-negative bacteria also cause food spoilage. Gram-negative bacteria include Salmonella spp., Shigella spp., Vibrio spp., Escherichia coli, Campylobacter jejuni, Yersinia enterocolitis, Brucella spp., Coxiella burnetii, Aeromonas spp., Plesiomonas shigelloides. Off-odors and off-flavors, discolorations, gas production, slime development, and pH reductions in food are all caused by these bacteria.

Microbes present in the food

Following are the common microorganisms present in the food.

  • Fungi

Fungi are the most common group of microbes present in food and also play a great role in food spoilage. It divides into mold and yeast.

Yeast does not produce toxic secondary metabolites. Yeast is beneficial for the fermentation process. They form colonies with high sugar and salt content and eventually contribute to food spoilage.

Molds are filamentous fungi. It is important in recycling dead plants and animals, but it also attacks food material. It causes off-flavor, mycotoxins contamination, discoloration and rotting.

  • Protozoa

It is associated with the food-borne and water-borne spread of diseases. It is a one-celled microorganism. Entamoeba histolytica, Cyclospora cayetanensis is some common food borne parasites.

  • Algae

Though algae are one of the sources of nutrition, they also cause food spoilage. They poison the water supply with their toxin, which accumulates in fish and marine life. When humans consume such fish or other marine life, they become unwell as a result of foodborne illness. Some examples include onyaulax catenella, Gonyaulax tamarensis, Ptychodiscus brevis, Microcystis aeruginosa and Blue-green Algae.

  • Viruses

Viruses need host cells to replicate. Food and water act as a carrier for them to transfer from one to another host.

Prevention of food spoilage

Some common methods used to prevent food spoilage are as follows:

  • Drying

It is one of the ancient food preservation techniques. In this method, water content is reduced to present bacterial growth.

  • Refrigeration

In refrigeration preservation, food is preserved by slowing down bacterial activity.

  • Vacuum packing

By vacuum packing the oxygen supply to microorganisms is cut off to preserve the food.

  • Preservation (salt, sugar)

Salting draws the moisture from the food. Some additives can also be used to stop food spoilage. Pickling is one of the ancient methods used to preserve food.

  • Canning

It involves the cooking or steaming of containers to kill the microorganism. Food varies in temperature to prevent spoilage. For example strawberries, high acid content fruit require short boiling to prevent spoilage.

  • Pasteurization

Food materials like milk can preserve by this method.

  • Smoking

The smoking method is used to increase the shelf life of perishable food items. In this method, the food material is exposed to smoke. Mostly meat and fish are preserved by this method. Few fruits and vegetables like paprika, cheeses, spices, and ingredients for making drinks such as malt and tea leaves are also preserved by this method.

Final thought

There are microorganisms present everywhere around the world. Microorganisms are beneficial and sometimes cause an adverse impact. The various methods can help to enhance the food quality.

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