Anaerobic Bacteria in Foods: Properties, Species and Hazards

Characteristics, Types, Hazards of Anaerobic Bacteria in Foods...

Characteristics of Anaerobic Bacteria

All bacterial species are divided into aerobic and anaerobic according to their relationship with oxygen. Aerobic bacteria respire in the presence of 21% O₂, which we call full oxygen concentration, while anaerobic bacteria cannot respire with oxygen.

Anaerobic bacteria are bacteria that lose their vitality or cannot reproduce in the presence of oxygen. In anaerobic bacteria, oxygen must be removed from the culture medium.

Anaerobic bacteria are divided into 3 groups.

Essential Anaerobic Bacteria
Aerotolerant Anaerobic Bacteria
Facultative Anaerobic Bacteria

Anaerobic bacteria are bacteria that can survive in the absence of oxygen. While these bacteria cannot reproduce or be active in the presence of oxygen, they show a high activity in the absence of oxygen. These bacteria are categorized in three main groups:

Obligate Anaerobes: They cannot survive in the presence of oxygen; they can only multiply in the absence of oxygen.
Facultative Anaerobes: They can survive in both oxygenated and anaerobic environments, but reproduce faster in the absence of oxygen.
Aerotolerant Anaerobes: They are not harmed in the presence of oxygen but do not use oxygen for energy production.

These bacteria break down substances in foods such as proteins and carbohydrates, producing various by-products such as gases, toxins and bad odors, especially in the absence of oxygen. Due to these characteristics, they can cause quality loss and spoilage in foods.

Types of Anaerobic Bacteria Found in Foods

Some species of anaerobic bacteria are likely to be present in foods and each is associated with different hazards and spoilage effects.

Clostridium Botulinum: One of the most dangerous anaerobic bacteria found in food . It produces a powerful toxin called botulinum toxin. It can be found especially in canned, smoked fish, pickled and packaged foods. It causes a serious food poisoning called botulism and can lead to death if left untreated. Botulinum toxin affects the nervous system and can cause respiratory paralysis.
Clostridium Perfringens: One of the common causes of foodborne illness. This bacterium has a high level of toxin production. It is often found in meat, broths, cooked dishes, dairy products and ready-to-eat foods. It causes food poisoning by damaging the digestive system. It causes symptoms such as diarrhea, stomach cramps and nausea.
Bacteroides spp: Found naturally in the human digestive system, but can multiply as a result of contamination in food. It can be seen especially in ready-to-eat foods and food production facilities that are not sufficiently hygienic. Normally non-pathogenic species are present, but some strains can cause gastrointestinal infections.
Clostridium sporogenes It has a similar structure to Clostridium botulinum and multiplies rapidly in oxygen-free environments. It is commonly found in canned foods and packaged meat products. It causes food spoilage by producing gas and can cause food poisoning if it produces toxins.
Lactobacillus spp: Some species are known as probiotics and are known as beneficial bacteria. They are naturally found in milk and dairy products and fermented foods. They are generally harmless, but can spoil the taste of food if present in high quantities as a result of production errors.

Harm Caused by Anaerobic Bacteria in Foods

Anaerobic bacteria can multiply rapidly in food due to improper storage conditions, lack of hygiene or processing errors. This leads to both food spoilage and risks to human health.

Food poisoning Toxins produced by some species, such as Clostridium botulinum, cause food poisoning that can be fatal. Botulinum toxin specifically targets the nervous system and can cause respiratory paralysis. Clostridium perfringens causes stomach cramps and diarrhea, leading to digestive disorders.
Food spoilage: Anaerobic bacteria cause gas, bad odor and color changes in foods, reducing the quality of the product. Especially in sealed and canned products, bacteria such as Clostridium sporogenes can cause the food containers to swell and burst by forming gas.
Shortening Shelf Life: The presence of anaerobic bacteria shortens the shelf life of foods. These bacteria multiply rapidly, especially in ready meals and packaged foods, reducing the freshness and reliability of products.
Taste and Odor Disturbances: By-products produced by anaerobic bacteria in foods can cause changes in the taste and odor of products. This reduces consumer satisfaction and reduces the commercial value of products.

Methods to Prevent Anaerobic Bacteria Contamination

Anaerobic bacteria can contaminate food due to lack of hygiene, storage conditions and processing errors. The following measures can be taken to ensure food safety:

Correct Storage Conditions: Storing food under appropriate temperature and humidity conditions prevents anaerobic bacteria from multiplying. It is particularly important to follow cold chain rules.
Pasteurization and Sterilization: High-temperature pasteurization and sterilization of foods helps to destroy anaerobic bacteria.
pH Control: Some anaerobic bacteria cannot multiply in a low pH environment. Lowering the pH level in fermented foods reduces bacterial growth.
Hygienic Production Conditions: Measures such as compliance with hygiene rules in food production, attention to personnel hygiene and equipment cleaning prevent bacterial contamination.
Vacuum Packaging and Canning: Vacuum packaging allows food to be preserved in an oxygen-free environment, but this environment can create an ideal breeding ground for anaerobic bacteria. Therefore, attention should be paid to hygiene and storage temperature in vacuum-packed products.

Nanolab Laboratories Group continues to provide services within the scope of Anaerobic Bacteria in Foods . We also provide services in Aerobic Colony Counting.

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