Production of fluorescence on packaged chicken.

Development of fluorescence caused by pseudomonads proliferating on packaged chicken was determined by examination of the poultry under ultraviolet light and by measurements of absorption spectra. Asparagine broth inoculated with organisms from chicken showed absorption maxima at 270 mmu and 410 mmu; these peaks are characteristic of the fluorescent pigment, pyoverdine. Absorbance calculated as the ratio (A(270mmu) + A(410mmu))/A(350mmu) provided a convenient measure of amount of pigment produced; this ratio was related to numbers of fluorescing organisms recovered from chicken. Absorption peaks generally increased during the first few days the poultry was stored at 5 C and then declined during the latter part of the 7-day holding period. Production of fluorescence was influenced by packaging materials. Fluorescence was not visible on poultry until counts of fluorescing bacteria were as great as 100,000 to 1,000,000 per cm(2). Growth of fluorescent pigment-producing pseudomonads on chicken was stimulated during storage after the poultry was dipped in solutions containing iron.