Knowing when poultry goes foul

Researchers at the National Institute of Standards and Technology (NIST) have designed an instrument that quickly and precisely sniffs trace amounts of chemical compounds that indicate poultry spoilage without damaging the product itself. The process can detect minute amounts of spoilage compounds and can be used by suppliers during all stages of processing, transport and storage.

Antibiotics and other chemical additives are commonly used to keep the poultry product from spoiling but, without invasive and time-consuming tests, it's hard to determine if the spoilage process has begun or not.

For several years, detection of volatile organic compounds created when lipids and/or proteins decompose has been used to test for spoilage. The technique developed by NIST research chemists Tom Bruno and Tara Lovestead relies on identifying the much more difficult-to-detect trace amounts of low-volatility compounds that are present early in the decay process. Analysing such low-volatility compounds used to require impractically long collection times to get a big enough sample for testing and identification.

The key to detecting minute levels of the low-volatility compounds produced when chicken spoils is a new method of sampling the ‘headspace’ - the air above a test sample. Bruno devised a technique using a short alumina-coated tube cooled to very low temperatures to promote the adsorption of low-volatility chemicals, a technique called cryoadsorption.

Among other advantages, Bruno's sampling method is robust and flexible in terms of where and how it can be used - an important feature for the food industry.

Bruno and Lovestead separated and identified six potential chemical markers that could be used to indicate poultry spoilage before it becomes unhealthy. Those markers were found in the air above spoiled chicken breasts, maintained in their original retail packaging and kept at room temperature for two weeks.