How to Fight Against Bacteria in Milk?

Milk is arguably one of the most versatile ingredients among cooks and a staple in most households. However, as an animal product that is full of nutrients, there are several infectious diseases associated with microbe-contaminated milk and milk products. Therefore, improving the hygiene quality of milk is crucial for consumer and producers of dairy.

Consumer will guarantee enjoy a good quality and far from food borne disease. Producers will be able to determine heat treatment procedures, shelf-life prediction and determining the suitability of raw milk for processing different products.

For decades, average levels of bacteria in raw milk have been gradually falling in Europe, US and most of dairies producers country. From millions of Colony Forming Units (CFU) per milliliter in seventies to less than 100.000 CFU per milliliter today. In many countries, producers constantly attain 10.000 cfu/ml in their raw milk deliveries.

For example, improvement in Denmark for milk quality:

Rapid results have proved important because catching hygiene breaches in raw milk early is essential for minimizing the impact on raw milk quality. Although pasteurization will kill majority of bacteria, their metabolites will cause off flavours and enzymes continue their activities resulting in product defects and reduction of shelf life. With faster information, farmers can be advised about possible problems allowing timely correction for leaks, insufficient cleaning or cooling in the milking system or health problem in the herd.

Public health awareness and demand for high quality milk increase government standard on milk quality. Legal limit standard for EU and US are as follow:

Applying bacteria in payment scheme is one of motivating factor for dairy producers to deliver high quality of milk. They will do their best for get more incentives as a good result.

Flow cytometry has growing acceptance among milk testing laboratories, industries as a rapid method for bacteria count. It has become standard methods for bacteria count on raw milk in many countries and this method already approved by European (EURL/Microval) and USA standard (NCMIS and FDA) and several national approvals, like Germany, France, Russia, etc.

Flow cytometry technology is used to analyze the physical and chemical characteristics of particles in a fluid as it passes through laser light.

The step are as follows:

1. Milk incubate, during incubation the cells are stained with a DNA-Specific, staining medium, a fluorescent dye
2. A precise syringe system is used to pass them through a flow cell one by one where they are exposed to a light beam from a laser sourced
3. The laser excites fluorescence from the dye and the stained cells emit one light pulse for every cell passing beam
4. The fluorescent light is detected by a highly sensitive detector which gives electronic impulses
5. The pulses are counted and displayed in a pulse height analysis diagram on the instrument screen.

Flow cytometry has widely used in many countries as standard for counting raw milk bacteria. More than 85 % of raw milk in Euro paid according to Bactoscan.

• Fast – Taking just a few minutes per test, flow cytometry is much faster than the traditional plate count method
• Traceable result and there is no influence by the operator.
• Consistent – The traditional plate count method is subject to test-to-test variables such as the sample preparation with petri dish, the timing of incubation period and a count by naked eye. In comparison, flow cytometry is an automatic, machine-based test which count with accuracy, repeatability and reproducibility. It can analyze raw milk samples directly without prior heating or dilution, which could otherwise affect precision.

Measuring bacteria traditionally takes two to three days to get the result. In early 70’s FOSS introduce the first BactoScan to analyze rapid result of Bacteria. The instrument can analyze Bacteria in less than ten minutes and it’s based on flow cytometry technology.