Sofos J N, Kochevar S L, Bellinger G R, Buege D R, Hancock D D, Ingham S C, Morgan J B, Reagan J O, Smith G C
Center for Red Meat Safety, Department of Animal Sciences, Colorado State University, Fort Collins 80523-1171, USA.
J Food Prot. 1999 Feb;62(2):140-5. doi: 10.4315/0362-028x-62.2.140.
This study determined microbiological loads of beef carcasses at different stages during the slaughtering to chilling process in seven (four steer/heifer and three cow/bull) plants. Potential sources of contamination (feces, air, lymph nodes) were also tested. Each facility was visited twice, once in November through January (wet season) and again in May through June (dry season). Carcasses were sampled by aseptic excision of surface tissue (100 cm2) from the brisket, flank, and rump (30 samples each) after hide removal (pre-evisceration), after final carcass washing, and after 24-h carcass chilling. The samples were analyzed individually by standard procedures for aerobic plate counts (APC), total coliform counts (TCC), Escherichia coli biotype I counts (ECC), and presence of Salmonella. Incidence of Salmonella was higher on dry feces of older compared to younger animals, fresh feces of younger compared to older animals, and on cow/bull carcasses compared to steer/heifer carcasses. Most factors and their interactions had significant (P < or = 0.05) effects on the bacterial counts obtained. Depending on plant and season, APC, TCC, and ECC were < or =10(4), < or =10(2), and < or =10(1) CFU/cm2 in 46.7 to 93.3, 50.0 to 100.0, and 74.7 to 100.0% of the samples, respectively. TCC exceeded 10(3) CFU/cm2 in 2.5% (wet season) and 1.5% (dry season) of the samples. ECC exceeded 10(2) CFU/cm2 in 8.7%, 0.3%, and 1.5% of the pre-evisceration, final carcass-washing, and 24-h carcass-chilling samples, respectively, during the wet season; the corresponding numbers during the dry season were 3.5%, 2.2%, and 3.0%, respectively. These data should serve as a baseline for future comparisons in measuring the microbiological status of beef carcasses, as the new inspection requirements are implemented.
本研究测定了七家屠宰场（四家屠宰阉牛/小母牛的厂和三家屠宰母牛/公牛的厂）中，牛胴体在屠宰至冷却过程不同阶段的微生物负荷。还对潜在污染源（粪便、空气、淋巴结）进行了检测。每家工厂都进行了两次走访，一次是在11月至1月（雨季），另一次是在5月至6月（旱季）。在去除牛皮后（去内脏前）、胴体最终清洗后以及胴体冷却24小时后，通过无菌切除胸部、侧腹和臀部的表面组织（100平方厘米）对胴体进行采样（每个部位30个样本）。通过标准程序分别对样本进行需氧平板计数（APC）、总大肠菌群计数（TCC）、I型大肠杆菌计数（ECC）以及沙门氏菌检测。与年幼动物相比，年长动物干粪便上的沙门氏菌发生率更高；与年长动物相比，年幼动物新鲜粪便上的沙门氏菌发生率更高；与阉牛/小母牛胴体相比，母牛/公牛胴体上的沙门氏菌发生率更高。大多数因素及其相互作用对所获得的细菌计数有显著（P≤0.05）影响。根据工厂和季节的不同，在46.7%至93.3%、50.0%至100.0%以及74.7%至100.0%的样本中，APC、TCC和ECC分别≤10⁴、≤10²和≤10¹CFU/cm²。在2.5%（雨季）和1.5%（旱季）的样本中，TCC超过10³CFU/cm²。在雨季，去内脏前、胴体最终清洗后以及胴体冷却24小时后的样本中，ECC分别有8.7%、0.3%和1.5%超过10²CFU/cm²；旱季的相应比例分别为3.5%、2.2%和3.0%。随着新检验要求的实施，这些数据应作为未来比较牛肉胴体微生物状况的基线。
