Microbiological Analysis in Food: Which Tests and How Often?

As a food producer or seller the question "which analysis should I have done, and how often?" comes up often. The answer depends on the product's risk group, shelf life, customer or buyer requirements and legislation. Microbiological analyses fall into three groups: hygiene indicators, pathogens and spoilage agents.

1. Hygiene indicators

• Total aerobic mesophilic bacteria (TAMB): An indicator of general hygiene and cold-chain quality
• Coliforms and E. coli: An indicator of faecal contamination and processing hygiene
• Enterobacteriaceae: An indicator of post-process contamination in cooked foods

If these indicators come out high there is a fault in production hygiene and pathogen risk has risen.

2. Pathogens

• Salmonella: For many foods such as meat, poultry, eggs, milk powder and spices there is a criterion "absent in 25 g"
• Listeria monocytogenes: Can multiply in the cold chain; critical for ready-to-eat foods
• Staphylococcus aureus and Bacillus cereus: Important in foods handled by hand and in rice and pasta dishes
• E. coli O157, Campylobacter: Tested in raw meat and dairy products by risk group

3. Spoilage agents

Yeast and mould, Pseudomonas and lactic acid bacteria determine shelf life and sensory quality. They matter especially in bread, dairy and fruit juice production.

How often?

As a general rule, the higher the risk the higher the frequency. For ready-to-eat cold-chain products (cheese, ham, ready salad) every batch or weekly; for dry food and spices every three months; for restaurants and catering monthly surface swab and sample analysis is recommended. A shelf-life study is done for a new product, new supplier or recipe change.

Surface and environmental monitoring

Product analysis alone is not enough. Production line surfaces, hands, ventilation and water should also be monitored regularly. With our hygiene monitoring package five surface swabs and two product analyses are done monthly; results are given as a trend report.

Practical tips

• Write the batch, production and expiry date on every sample
• Send the sample in the cold chain and within 24 hours
• Take at least 250 g of the same product; do not open the sealed pack

You can look at the basic microbiology package in our Packages section and fill in the sample submission form.

How are results interpreted?

Results are compared with the product-specific limits in the Turkish Food Codex Microbiological Criteria Regulation. A hygiene indicator exceeding its limit often shows a systematic weakness in the process rather than a one-off error; so looking at the trend across several batches, not a single result, leads to better decisions. Our trend reports make this interpretation easier.