Sensory aroma characteristics of milk spoilage by Pseudomonas species

Sensory characteristics of the spoilage aromas of milk containing Pseudomonas species were determined. Two strains each of P. fluorescens, P. fragi, and R putida were evaluated. Milk (skim and whole) was double-steamed and inoculated with 10(3) CFU/mL (ca) of Pseudomonas. Milk samples were stored at 5degreesC for 1 mo. Plate counts were conducted every 31 day to determine growth rates. Descriptive aroma analysis was conducted weekly (n = 4) using 10 trained panelists. All 6 strains grew at refrigeration temperatures and there was no difference in growth among strains. Type and onset of spoilage depended on strain of Pseudomonas and milkfat content. This information may aid in shelf-life prediction of milk.