Viability of Listeria monocytogenes, Staphylococcus aureus and psychotrophic spoilage micro-organisms in refrigerated ground beef supplemented with sucrose esters of fatty acids

Abstract

Populations of Listeria monocytogenes, Staphylococcus aureus and naturally occurring psychotrophic micro-organisms in ground beef supplemented with food-grade sucrose esters of fatty acids were monitored for up to 7 days of storage at 5 or 15°C. Populations of L. monocytogenes in beef containing sucrose laurate (0·30 and 0·49%) or sucrose palmitate (0·32%) were significantly lower (P≤0·05) than populations in the control beef after 1, 2, 4 and 7 days of storage at 5 °C. Ground beef containing 0·32% sucrose palmitate which was stored at 15 °C also contained significantly lower populations of L. monocytogenes throughout the 7-day storage period. No significant (P ≤ 0·05) differences in populations of S. aureus were observed in beef supplemented with sucrose stearate (0·23 and 0·32%) or sucrose oleate (0·09 and 0·15%) when storage was at 5 °C. At 15 °C, inhibition of S. aureus by sucrose laurate, sucrose palmitate and sucrose stearate was significant through day 4. Sucrose oleate (0·15%) was without affect at 15 °C for both pathogens. Populations of psychrotrophs were significantly less (P≤0·05) in beef containing 0·30 or 0·49 sucrose laurate through day 2, regardless of the storage temperature. Supplementation with sucrose esters of palmitic (0·32%), oleic (0·15%) and stearic (0·32%) acids failed to control the growth of naturally occurring psychrotrophic micro-organisms. Studies to determine the effects of higher concentrations of sucrose esters of fatty acids on survival and growth of bacterial pathogens and psychrotrophs in ground beef are warranted.