Microbiological Analysis

Fridge showing food and beverages (meat, poultry, dairy, eggs, fruit and vegetables) that require microbiological testing for food safety and quality

Microbial food and beverage testing is the determination of microorganism contamination levels during the manufacturing process and in final consumer products. Microbial testing involves the application of biochemical and molecular methods for the detection, identification, or enumeration of microorganisms in a product.

Importance of microbiological testing in food and beverages

Food Safety and Standards Act guidelines help food and beverage manufacturers maintain product safety and quality. Identification of pathogen and food spoilage microorganisms is a vital part of food microbiology to ensure consumer safety, prevent brand desecration, and minimize costly mitigation following failed inspections or food poisoning outbreak. Key factors to be considered in a microbial testing program include frequency of testing, ideal production stage for testing, matrix or product composition, target spoilage organism, and testing methods.


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Bacterial and fungal contamination in food production are associated with various foodborne illnesses with symptoms that range from mild nausea to severe gastrointestinal poisoning and death.

Microbial spoilage screening of beverages is also crucial to ensure the release of safe drinks to the market.

Loss through spoilage can be costly for producers of beverages, irrespective of whether it affects ingredients or a finished product. It may have even more severe consequences when the spoilt final product reaches the market. In addition to the monetary loss incurred because of the bad product and its recall, customer confidence and the brand image may also be seriously degraded.

Microbiological QA/QC applications in food and beverage testing

Microbial tests ranging from quantitative and qualitative significantly contribute to the identification of food and outbreak of foodborne diseases. These routine tests can be used to validate primary control methods, such as the Hazard Analysis and Critical Control Point (HACCP) system. Routine microbiological solutions cover the entire production process through to the QA/QC analysis of products while ensuring compliance with regulatory standards. They include:

  • Hygiene monitoring for microbiological analysis of air, surfaces and personnel (HACCP management and ATP Testing)
  • Water testing
  • Pathogen testing
  • Indicator organism testing
  • Spoilage organism testing

Food spoilage microorganisms

Food spoilage, often recognized by degradation of texture, flavor, or nutritional value, can be caused by yeast, mold, and bacteria. There are two types of yeast that can cause spoilage. True yeast metabolizes sugar and produces alcohol and carbon dioxide gas by a process known as fermentation. False yeast occurs as dry film on the surface of food with high sugar or acid content. Mold on food is visible, as mold growth is formed by filaments. In a manufacturing facility, containing microbial exposure is a constant challenge, as mold spores can float through the air to find suitable conditions to grow again. Yeast and mold can be found on high acid food items, such as fruits and pickles, while bacteria prefer low acid food products, such as meat and vegetables. Different types of spore-forming or non-spore-forming bacteria can also cause spoilage.

Dangerous foodborne illnesses are often caused by opportunistic bacterial pathogens, including Salmonella, that can survive on poultry, meat, or eggs; E. coli that contaminates beef and vegetables; and Listeria that predominantly affects dairy and long shelf life prepared foods.

Food microbial testing requirements

Food processing, manufacturing, and quality control requires in-process testing for specific microorganisms. Requirements vary from industry to industry, depending on the spoilage parameters for each food and beverage type. The product’s perishability typically defines if traditional or rapid testing methods are necessary. Traditional methods usually include plating and culturing samples for microbial identification. Rapid methods use molecular probes to detect microbial DNA signatures and are considered alternative methods if not specifically described in USDA, FDA, ISO, or other standards. Rapid methods are often preferred when a shorter analysis is needed to release food samples, especially for meat and other food products with a short shelf life. Alternative methods are applicable if validated according to ISO 16140 or AOAC international guidelines and accepted by the corresponding regional government.





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