An important criterion of marketability of food products is their microbiological importance. When the statutory tests are made, required by the low, manufacturers focus on quickness. How these two criteria can be reconciled? This was the topic of the professional day organised in the WESSLING Knowledge Centre, where new, safe and quick methods were introduced by the specialists.
Most food-born disease is of microbiological origin even today (about 9 million and minimum 15 to 20 thousand justified cases per annum in the USA and in this country, respectively), while frequent travelling and the international food trade enhances the opportunities for spreading pathogen bacteria further – said Dr. Attila Fekete, officer from NÉBIH at the microbiology professionals day this year, organised by the independent laboratory with a more than 25 years of domestic history, WESSLING Hungary Kft. where the main goal was to feature state-of-the-art solutions to reduce decision related risks.
Albeit food industry makes attempts to reduce the levels of risks, conventional microbiological methods are not quick enough (it takes 5-8 days to cultivate and identify an pathogen agent) and are also too labour intensive, the expert added, who – beside describing the legal background – called the attention of the audience to the fact that an explosive development was observed in food microbiology in the past three decades.
Food industry needs nowadays quick, simple and accurate methods, accepted and validated by authority and partners – said Edit Pocklán, staff member of Wessling Hungary Kft. The demand for quick microbiological test methods are directed mostly to the identification of Salmonella, Listeria monocytogenes, E.coli O157, and Campylobacter, primarily from meat, milk, poultry, sweets, cereals and processed food products.
Modern test laboratories try to provide the most appropriate diagnostic answers to these problems. On the Department of Microbiology at WESSLING Hungary Kft. for instance, methods based on both molecular biological and immunological principles are applied.
Molecular biological methods – detection of pathogens based on PCR
The polymerase chain reaction (PCR) developed in the middle of the eighties in the last century revolutionised molecular diagnostics. The PCR methodology can be conveniently used to detect pathogen agents occurring in food products. The sensitivity of the new methods grew significantly. A great advantage of the PCR detection is that negative results can be obtained within 24-30 hours, easy to use, the detection limit is low, and has a great capacity; it is designed to handle hundreds of samples at a time.
MALDI-TOF method: fields of use
Zsanett Simon (also from WESSLING Hungary Kft.) said that MALDI (Matrix Assisted Laser Desorption / Ionisation) functioning on the principle of mass spectrometry identifies pathogenic agents based on the genetically determined proteins and protein compositions found in the micro-organisms. Cultivation conditions – growth medium, state of development, temperature – influence the quality of the spectrum and the outcome of the identification only to a slight extent.
In the course of the MALDI-TOF microbiological tests hygienic contamination is determined among others in the laboratory (surface, working surfaces in direct contacts with the food item, packaging materials), Staphylococcus epidermidis is distinguished from St. aureus, and the results of the biochemical tests are confirmed.
While microbiological identification requires sometime several days and multiple, different cultivation media, the operational costs are quite high and strain level identification is mostly impossible, MALDI-TOF performs well even within an hour without any preliminary identification, does not require any preparations and provides the opportunity for strain level identification – was stated on the professional day, the lectures of which can be downloaded from here: