Testing for microbial contamination in brewing and food production
Rapid identification of microbes is an essential quality control step to ensure that only the intended microorganisms chosen by the producer are present.
Advanced testing systems used in hospitals worldwide are now being adapted for use within the food and beverage industry to enable rapid, cost-effective and high-throughput screening.
A new service developed with a leading brewing company in Australia has made this possible and tests are now available for the beer brewing industry (1).
As new tests are developed for the following markets we will make these available to Australian producers:
- Brewing (beer and cider)
- Fresh Juice
- Fermented beverages
An example of microorganism identification for quality control testing within the brewing industry has been recently published in Applied Microbiology and Biotechnology by Adelaide Proteomics Centre researchers.
Turvey et al. (2016). Identification of beer spoilage microorganisms using the MALDI Biotyper platform. Appl Microbiol Biotechnol. Doi 10.1007/s00253-016-7344-8.
Further information on these services can be found below.
- Mass Spectrometry Profiling using the Biotyper Platform
The MALDI Biotyper platform uses mass spectrometry profiling for the rapid identification of microorganisms (bacteria, fungi, mould species) by matching acquired mass spectrum patterns against a large commercial database of reference profiles.
Soluble proteins are extracted from microorganism samples and are analysed by Matrix Assisted Laser Desorption/Ionisation Time-Of-Flight Mass Spectrometry (MALDI-TOF MS), where proteins are separated based on mass, thereby creating a mass spectrum pattern unique to the organism to the species level.
Sample Delivery and Processing
Samples are required to be in the form of standard microbiology agar plates with distinct colonies, stored at 4°C and sealed for transport and delivery to the Adelaide Proteomics Centre, The University of Adelaide. Colonies for analysis should be circled or plates annotated accordingly if all colonies are to be analysed. Service staff at Adelaide Proteomics will perform an extraction of soluble proteins and samples will be spotted onto a MALDI target plate for mass spectrometry analysis.
MALDI Acquisition and Analysis
Adelaide Proteomics Centre is equipped with three matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI MS) instruments set up for Biotyper analyses, Bruker Ultraflex III, UltrafleXtreme and Autoflex Speed. Microorganism samples are analysed, then acquired mass spectra are uploaded to the Biotyper software (Bruker Corporation) (version 3.1.66) and identifications are made by matching the acquired spectra against the database of mass spectrum profile reference spectra. A report is generated with identification and scores for microorganism samples.
A standard set-up fee of $110 per experiment sample batch applies to cover consumables, labour and mass spectrometry instrument time, then cost per sample applies as follows:
Pricing Sample Measure Cost Per Sample 1 to 10 samples $25 11 to 20 sample $20 21 to 50 sample $15 50+ samples $10
Refer to Adelaide Proteomics Centre website for full Proteomics Services list and pricing information
- Key Contact
- Research Opportunities
Biotyper analyses can be extended to investigate small differences between sub-types of a species, or small differences between the same species under different growth/stress conditions. Adelaide Proteomics Centre is currently investigating methods for the sub-typing of closely related strains of bottom-fermenting Saccharomyces pastorianus brewing yeast, in addition to modelling the health and performance of brewing yeasts using Biotyper profiling through fermentation and propagation cycles.
Identifying new organisms
The Biotyper platform was originally created for use in the clinic, therefore, the existing database consists predominately of entries representing bacterial, fungal and mould species that are relevant to human infection and disease. Some non-human pathogens may therefore not have an entry in the current database. These microorganism samples, which produce a unique mass spectrum profile but cannot be identified using the current Biotyper database, can be identified by liquid-chromatography mass spectrometry at the Adelaide Proteomics Centre. See Protein Identification by MS/MS (peptide sequencing.
Creating business-specific local databases
In-house local databases can be created and tailored for individual businesses and production facilities within the food and beverage industry for routine quality control practices. Together, a collaboration between a local business and Adelaide Proteomics Centre would be set up in order to identify spoilage microorganisms relevant to the business and generate mass spectrum profile reference spectra for these microorganisms to be incorporated into a business-specific database.
For information regarding South Australian Government Department of State Development funding for research collaborations with Adelaide Proteomics Centre and the Institute of Photonics and Advanced Sensing, see the Photonics Catalyst Program.