Counts of psychrotrophic bacteria showed mostly nonsignificant differences (p > 0.05) between treated and untreated beef patties and among treatments throughout the 24 d of storage (results not
shown).
Initial counts were about 4.0 cfu/g, and reached 7.0 cfu/g at 12 to 16 d for all of the samples.
These results indicated that all of the beef patties ought to be considered microbiologically unacceptable after 12 to 16 d of storage.
Nevertheless, some small but significant differences (p < 0.05) were apparent only at d 8 and 12 of storage; namely, all the patties treated with rosemary, oregano, and borage had mean counts those days within the range 5.08 and 5.56
cfu/g, and 6.36 and 6.69 cfu/g, respectively,
while control patties had counts of 5.94 and 6.99 cfu/g; thus indicating a small prolongation
of the lag phase of microbial growth.
These results, though of limited significance, seem to be in agreement with those reporting
the antimicrobial properties of plant essential oils or extracts of rosemary and oregano .
No data on any antimicrobial
effect of borage meal have been found thus far.