Clostridium estertheticum QPCR
ONLINE SUBMISSION FORM FOR CLOSTRIDIUM ESTERTHETICUM
"Blown-pack" spoilage of venison due to Cl. estertheticum. Left - grossly distended packaging, centre - loose packaging, right - normal vacuum packaging
Clostridium estertheticum causes "blown-pack" spoilage of vacuum-packed chill-stored raw beef, lamb and venison by the production of gas (hydrogen and carbon dioxide) and foul smelling sulphurous compounds. Vacuum-packs may become grossly distended with gas if contaminated with high numbers of Cl. estertheticum, or may just appear loose if contaminated with lower numbers. Invariably contaminated vacuum-packed meat has a foul smell when opened. Cl. estertheticum "blown-pack" spoilage causes substantial economic losses to the meat industry each year.
Since 1997 we have offered the meat industry a polymerase chain reaction (PCR) assay to detect Cl. estertheticum in samples taken from meat and the abattoir environment. In 2003 we developed a state of the art quantitative (Q) PCR to detect and quantify Cl. estertheticum in samples submitted for testing by the meat industry. To date we have used this assay to test more than 26,000 samples for the meat industry.
In 2008 we performed over 7500 Cl. estertheticum QPCR tests and in 2009 we performed over 6900 tests.
A typical plain cotton tipped swab
Samples
Suitable samples include, plain cotton swabs (see illustration), meat, or drip from vac-packed meat. We normally request that swab samples are collected using plain dry swabs, moistened if necessary (e.g. for environmental samples) with sterile water or diluent such as peptone saline (maximum recovery diluent). Swabs can be sent through the post without cool bags.No transport medium of any kind should be included. In particular, do not use swabs that have been dipped in "neutralising diluent", as this usually gives invalid results.
Two-fold dilution showing the quantitative nature of QPCR - samples containing more DNA are detected at an earlier cycle number than samples containing less DNA
Quality control
All samples are spiked with an internal amplification control (IAC) DNA and subjected to nucleic acid purification. QPCR is then performed to detect Cl. estertheticum and the IAC simultaneously in every sample. To ensure sample DNA has been extracted correctly and lacks PCR inhibitors we compare the IAC result for each sample to a known IAC control sample. Suitable QPCR controls are also included in every run to determine assay validity. Samples with IAC results significantly different to the known IAC control are deemed invalid. Normally we find between 1 - 2 % of results are invalid and for these samples we repeat the QPCR after re-extracting the DNA, almost all samples then give a valid result. We do not charge the customer extra for this.
Quantification
Samples with valid IAC results have their Cl. estertheticum result scored between zero and 10 (zero being no Cl. estertheticum detected and 10 being the highest level we have ever detected). There is approximately a 10-fold difference in the number of Cl. estertheticum between each point on the scale.
Submission of samples
Samples, as described above, should be submitted along with a purchase order number and contact details to the following address.
Dr Janet Corry / Ms Laura Cavill
University of Bristol
Langford
Bristol
BS40 5DU
The test is usually performed twice a week on Tuesday and Thursday with results being emailed by Wednesday and Friday.
Cl. estertheticum QPCR cost
Between 1 and 19 samples - £25+VAT per sample.
Twenty or more samples - £23+VAT per sample.
Contact details
Dr Janet Corry: Tel 0117 928 9409
Dr Chris Helps: Tel 0117 928 9242