Vieira et al. (2009) found in their study that beef frozen for up to
90 days, previously aged for 3 and 10 days, did not spoil due to microbial
growth. They did, however, report an increase in the levels of
psychrotrophic bacteria during the 90-day frozen storage, which
were probably favoured above the other bacteria by the thawing
process (48 h at 4 °C in a cooler). Greer and Murray (1991) found
that the lag phase of bacterial growth in frozen/thawed pork was
shorter than for fresh meat, but that the time to develop spoilage
odours was not affected. Literature on the microbial quality and
shelf-life post freeze/thaw is scarce for all species of meat, but that
which is available seems to indicate that the microbiological shelflife
of fresh and frozen/thawed samples is similar.