Reliable sampling with aseptic sampling bag

When VitaLys I/S takes sterile samples from the company’s fermentation tanks, it does so using Keofitt’s aseptic sampling bags. Although it is a more costly solution, VitaLys believes it has paid for itself many times over since it means the company avoids rejecting a batch on the basis of unreliable results

Application: Lysine for animal feed
VitaLys I/S
Keofitt products:
Keofitt Aseptic Sampling Bags & Keofitt Ingold Sampling Valve



Biotechnology manufacturing processes such as those used within, for instance, the food and beverages industry and the pharmaceutical industry, often involve fermentation processes that must be checked regularly in order to prevent contamination by undesirable microorganisms. In order to ensure that the sample which is removed for testing is identical to the content of the fermentation tank and has not been infected by unwanted microorganisms during the actual sampling procedure, the sampling process must be performed under sterile conditions.


Patented manufacturing process

VitaLys I/S in Esbjerg manufactures VitaLys, a lysine product produced by means of fermentation using selected Coryne bacteria. Lysine is an essential amino acid used in, among other things, pig and poultry feed. It ensures optimal feedstuff utilization, better growth rate and an improved meat quality. The high-technology production of VitaLys is based on the company’s own patented process and the latest expertise within the fields of biotechnology, fermentation and process technology. The production method is environmentally friendly since it employs by-products from agriculture and produces no waste products.

VitaLys supplies both a liquid concentrate and a spray-dried product in powder form. The main customer is the Danish feedstuff company DLG, joint owner of VitaLys I/S. The company also supplies other customers on the Northern European market. The annual production is approx. 18,000 tonnes.


Specially developed sampling valve

The actual fermentation process last five days and takes place at first in smaller tanks and thereafter in 440 m3 stainless steel tanks. During the course of these five days, five samples are collected from the ferment. Sampling is conducted using a specially developed sampling valve from Keofitt A/S. The Keofitt valve is designed with a vapour barrier that ensures all the valve’s interior parts are sterilized both before and after sampling. The valves used by VitaLys are also fitted with a special sampling point for removing samples.


Keofitt’s aseptic sampling bags are used for two of the five samples in a batch. During sampling, the bag’s inlet is sterilized using steam before ferment is drawn off into the bag. In order not to destroy bacteria in the sample, the ferment is drained off at the start – when the inlet is hot from the steam – into an outlet chamber until the temperature is reduced.


Sampling bag pays for itself many times over

“Previously we used a sterile glass sampling container below the valve for all five samples. This carried the risk of unwanted bacteria from the surrounding air contaminating the sample and subsequently contaminating – or polluting – the samples. Now and then we’d end up with indeterminate samples which led us to interrupt the fermentation process or to carry on regardless of any problems. That meant a loss of production – we once had to scrap an entire tank of 440 m3,” explains Anne-Mette Jakobsen, process engineer at VitaLys I/S.


By using Keofitt’s aseptic sampling bags for some of the samples we can ensure our sampling process is 100% reliable, so even though it’s a more costly solution it has paid for itself many times over. Previously, we would occasionally end up with indeterminate samples which led us to interrupt the fermentation process unnecessarily or to carry on regardless of problems. That resulted in a loss of production, and consequently a loss in earnings. We once had to scrap a whole tank of 440 m3.


New method improves detection limit a thousandfold

Apart from improving the quality of VitaLys’ sampling process, the use of Keofitt’s aseptic sampling bags has also meant that one of the company’s laboratory technicians, Laila Bleeg Smidt, has developed a method that improves the detection limit for bacteria in the samples by a factor of 1,000.


“A single unwanted bacteria in the bag and, correspondingly, more unwanted bacteria in the tank, can ruin an entire production,” says Laila Bleeg Smidt. She continues: “There’s no guarantee that you’ll ‘catch’ that one unwanted bacteria in the 0.1 ml sample which is usually taken from the bag. Because of that, we have developed a method to detect these bacteria in the sampling bag itself.”


Highly reliable results

“Once the necessary samples have been extracted from the bag, a nutritional broth is added to the ferment in the bag using a needle inserted through the sampling membrane in the bag. One day later – after the bag has been stored in an incubator – that one bacteria will have multiplied to around 4,000 which means that a 0.1 ml sample contains a minimum of two bacteria. We can therefore be highly certain of obtaining a correct result in the subsequent analysis of the sample,” concludes Laila Bleeg Smidt.