Chilled and frozen storage 211 □ Pseudomonas wE8 4 2 Fig. 10.2 Growth of bacteria on naturally contaminated beef-brisket fat stored at 5C(source: Lasta et aL., 1995) promised. There appear to be no clear scientific studies that store carcasses under a range of industrial conditions to prove or disprove this belief. Iny tigations on pork chilling( Greer and Dilts, 1988) have shown that while conventional chilling significantly reduces the level of mesophilic bacteria, boning there was no signe y chilling. However, this work found that after duced by either treatment. Other studies found no difference in off-odours during storage and retail display of pork chops from pork cooled under either of the two methods, though the appearance of the spray chilled samples deteriorated slightly faster than those treated conventionally (Jeremiah and Jones, 1989) 10.2.2 Wrapped meat TTT(time-temperature-tolerance )and PPP(product-process-packaging) factors significantly influence the storage life of chilled meat (Bogh Sorensen et al., 1986). In some cases the initial processing stage can hay more effect than the subsequent storage conditions. After manufacture, sausages made from hot-boned pork had higher total bacterial counts (4.1 loglo cfug")than those from cold-boned meat(2.7 logo cfu 1g")(Bentley et al., 1987). When they were stored at 4 or -1C for 28 days there were no differences between counts at the two temperatures. However, the counts were very high, 8.7 and 8.9 logo cfug", in both cases. In vacuum-packaged primals, Egan et al.(1986)have shown that the tem perature of storage and ph determines both the storage life and the nature of the changes during storage(Table 10.3) Flora on high pH (>6.0) beef cuts, vacuum packaged in polyvinylidene chloride(PVDC) reached maximum levels in 6 weeks at 1C comparedpromised. There appear to be no clear scientific studies that store carcasses under a range of industrial conditions to prove or disprove this belief. Inves￾tigations on pork chilling (Greer and Dilts, 1988) have shown that while conventional chilling significantly reduces the level of mesophilic bacteria, this does not occur when spray chilling. However, this work found that after boning there was no significant difference in bacterial counts on loins pro￾duced by either treatment. Other studies found no difference in off-odours during storage and retail display of pork chops from pork cooled under either of the two methods, though the appearance of the spray chilled samples deteriorated slightly faster than those treated conventionally (Jeremiah and Jones, 1989). 10.2.2 Wrapped meat TTT (time–temperature–tolerance) and PPP (product–process–packaging) factors significantly influence the storage life of chilled meat (Bøgh￾Sørensen et al., 1986). In some cases the initial processing stage can have more effect than the subsequent storage conditions. After manufacture, sausages made from hot-boned pork had higher total bacterial counts (4.1 log10 cfu g-1 ) than those from cold-boned meat (2.7 log10 cfu g-1 ) (Bentley et al., 1987). When they were stored at 4 or -1 °C for 28 days there were no differences between counts at the two temperatures. However, the counts were very high, 8.7 and 8.9 log10 cfug-1 , in both cases. In vacuum-packaged primals, Egan et al. (1986) have shown that the tem￾perature of storage and pH determines both the storage life and the nature of the changes during storage (Table 10.3). Flora on high pH (>6.0) beef cuts, vacuum packaged in polyvinylidene chloride (PVDC) reached maximum levels in 6 weeks at 1°C compared Chilled and frozen storage 211 10 8 6 4 2 0 0 2 4 7 9 11 14 Days at 5 °C Log cfu cm–2 Total Gram negs Pseudomonas Fig. 10.2 Growth of bacteria on naturally contaminated beef-brisket fat stored at 5 °C (source: Lasta et al., 1995)