Volatile components present at spoilage of refrigerated chicken breasts were identified using high-vacuum-low-temperature distillation techniques followed by analysis with combined temperature-programmed gas chromatography and mass spectrometry. A comparison was made of the compounds detected from both irradiated and non-irradiated muscle stored at 2 and 10°C under both aerobic and anaerobic conditions. Isolates were randomly selected from the spoiled poultry, identified, and evaluated for their ability to produce volatile spoilage notes when grown on radiation-sterilized chicken. Several isolates that produced off-odors on sterile chicken breasts were examined. Twenty-two compounds were associated with spoilage. Some of the compounds found on both irradiated and unirradiated samples were considered to play only a minor role in the spoilage aroma or were present in low concentrations, since the aroma of spoiled irradiated chicken lacked the harsh odor notes typical of spoiled unirradiated chicken. Fifteen of the 22 compounds were considered to be unique to unirradiated, aerobically spoiled samples. Nine of these compounds, hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, methyl acetate, ethyl acetate, heptadiene, methanol, and ethanol, were found on chicken spoiled at both 2 and 10°C. Xylene, benzaldehyde, and 2,3-dithiahexane were detected only in samples stored at 20C and methyl thiolacetate, 2-butanone, and ethyl propionate were associated with 10°C spoilage. Fifty-eight isolates randomly selected from fresh, radiation-pasteurized, and unirradiated spoiled poultry were classified taxonomically, and 10 of them, which produced spoilage odors on sterilized chicken breasts, were selected for subsequent analysis of their volatiles. Isolates identified as Pseudomonas putrefaciens and Pseudomonas species that were members of groups I and II of Shewan's classification, as well as Flavobacterium and oxidative Moraxella, produced a number of the compounds found in the aroma of spoiled chicken. A total of 17 compounds were identified. Whereas no isolate produced all of the aroma compounds found in the aroma of spoiled chicken, together they did produce the nine found in unirradiated samples spoiled at either 2 or 10°C, as well as methyl thiolacetate and xylene. Six compounds were present in the volatiles produced by the isolates but were absent in the volatiles identified from spoiled chicken. These were hydrogen cyanide, methyl isopropyl sulfide, 2-propane thiol, methyl propionate, ethyl benzene, and an unidentified compound. The spoilage odor of meat, poultry, and fish at refrigeration temperatures is attributed mainly to microbial by-products (2, 10, 13, 15) and not to autolytic products from tissue (10, 13, 17). Whereas spoilage odors have been subjectively described (1, 14, 15), only recently have attempts been made to identify specific volatile compounds present at spoilage and relate them to the causative microorganism.

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Three different strains of bacteria isolated from spoiled, uncooked chicken were grown in pure culture on Trypticase soy agar supplemented with yeast extract. The volatile organic compounds produced by each culture were concentrated on a porous polymer precolumn and analyzed by high-resolution gas chromatographic mass spectrometry. Twenty different compounds were identified. Both qualitative and quantitative differences in the chromatographic profiles from each culture were found.

Four different fluorescent pseudomonads were isolated from spoiled, uncooked chicken breasts and were grown in pure culture on initially sterile chicken breast muscle at 2 to 6°C for 14 days. The volatile compounds produced by each culture were concentrated on a porous polymer precolumn and separated and identified by high-resolution gas chromatography-mass spectrometry.

Four pseudombnad cultures (one P. putida one nonpigmented, and two P. fluorescens) were isolated from spohed chicken breasts held at 2-6°C for 14 days. Each culture was grown on psychrotroph-free chicken skin for 14 days at 2-6'C. The volatiles produced by each organism were separated by high-resolution gas chromatography and identified by mass spectrometry. Some of the more significant volatile spoilage compounds produced by these microorganisms were sulfur-containing, e.g. methanethiol, dimethyl sulfide, propylene sulfide, and dimethyl disulfide.