calf herds are similar with respect to E. coli O157:H7”: it is not clear what regarding O157:H7 is similar.
Page 51: “Five studies provide evidence on apparent within-feedlot”: insert the word “prevalence” after that phrase.
Page 51: “…this protocol is assumed to be 100% sensitive”: a reason should be provided for this assumption.
Page 53: The age of breeding cattle is more likely 3, instead of 2, years; most feedlot cattle should be 1–2 years old.
Page 56: Truckloads of cattle from different feedlots are not usually mixed at slaughter.
Page 65: The draft risk assessment cites Sheridan et al. (1992) as having identified such equipment as knives, gloves, and aprons as reservoirs of bacteria in the slaughterhouse. That is correct, but the reference also indicates that “the level of contamination varied with different cuts of meat,” which may affect the extent of contamination of trim. There is also a typographic error in the citation: Meat Science 32:185–194, rather than 32:155–164.
Page 66: Contrary to what is stated in the draft, no “excess fat is trimmed away from each side” of the carcass at splitting (before washing), although blood-soiled tissue may be trimmed.
Page 67: The draft asserts that distilled water and chlorine are occasionally sprayed on carcasses in chillers (Step 6). Carcasses are spraychilled with water but not with distilled water or chlorine (which causes corrosion). Lactic acid may be in the initial stages of finding some use in this application.
Page 67: “FSIS regulations require chilling deep muscle (6 inches) to 10.0°C (50.0°F) within 24 hours and 7.2°C (45.0°F) within 36 hours (NACMCF, 1993)”: this may be done in practice but to the committee’s knowledge, is not required by the Food Safety and Inspection Service; if it is, a more direct reference should be provided.
Page 67: “Dorsa (1997) found a 1.2 log CFU/cm2 increase in E. coli O157:H7 on carcasses stored for 2 days in the chiller at 5.0°C (41.0°F)”: It appears that the correct reference may be Dorsa et al. (1997), not Dorsa (1997). Instead of carcasses, the study evaluated inoculated beef-carcass tissue samples that were decontaminated and packaged, thus simulating retail products rather than carcasses. In addition, it is questionable whether E. coli O157:H7 would grow at 5°C.
Page 68: “Prasai et al. (1995) found no difference in concentrations of E. coli O157:H7 between hot deboning and cold deboning”: it appears that the Prasai et al. (1995) reference listed does not deal with E. coli O157:H7 or hot or cold deboning.
Page 70: The carcass surface areas estimated to end up in ground beef