Poultry Microbiological Safety Research Unit, Russell Research Center, U.S. Department of Agriculture, Agricultural Research Service, Athens, Georgia 30604, USA.
J Food Prot. 2011 Sep;74(9):1558-63. doi: 10.4315/0362-028X.JFP-11-024.
An instrument (TEMPO) has been developed to automate the most-probable-number (MPN) technique and reduce the effort required to estimate some bacterial populations. We compared the automated MPN technique with traditional microbiological plating methods and Petrifilm methods for estimating the total viable count of aerobic microorganisms (TVC), total coliforms (CC), and Escherichia coli populations (EC) on freshly processed broiler chicken carcasses (postchill whole carcass rinse [WCR] samples) and cumulative drip-line samples from a commercial broiler processing facility. Overall, 120 broiler carcasses, 36 prechill drip-line samples, and 40 postchill drip-line samples were collected over 5 days (representing five individual flocks) and analyzed by the automated MPN and direct agar plating and Petrifilm methods. The TVC correlation coefficient between the automated MPN and traditional methods was very high (0.972) for the prechill drip samples, which had mean log-transformed values of 3.09 and 3.02, respectively. The TVC correlation coefficient was lower (0.710) for the postchill WCR samples, which had lower mean log values of 1.53 and 1.31, respectively. Correlations between the methods for the prechill CC and EC samples were 0.812 and 0.880, respectively. The estimated number of total aerobes was generally greater than the total number of coliforms or E. coli recovered for all sample types (P < 2e⁻¹⁶). Significantly more bacteria were recovered from the prechill samples than from the postchill WCR or cumulative drip samples (P < 9.5e⁻¹² and P < 2e⁻¹⁶, respectively). When samples below the limit of detection were excluded, 92.1% of the total responses were within a single log difference between the traditional plating or Petrifilm methods and the automated MPN method.
一种仪器（TEMPO）已经被开发出来，可以实现最可能数（MPN）技术的自动化，并减少估计某些细菌种群所需的工作量。我们将自动化 MPN 技术与传统微生物平板计数方法和 Petrifilm 方法进行了比较，以估计新鲜加工的肉鸡胴体（冷藏后整个胴体冲洗[WCR]样品）和来自商业肉鸡加工厂的累积滴线样品中的需氧微生物总数（TVC）、总大肠菌群（CC）和大肠杆菌（EC）的总数。总体而言，在 5 天内（代表五个单独的批次）共采集了 120 个肉鸡胴体、36 个预冷滴线样本和 40 个冷藏后滴线样本，并通过自动化 MPN 和直接琼脂平板计数和 Petrifilm 方法进行了分析。预冷滴线样本中，自动化 MPN 和传统方法之间的 TVC 相关系数非常高（0.972），其对数转化平均值分别为 3.09 和 3.02。冷藏后 WCR 样本的 TVC 相关系数较低（0.710），其对数转化平均值分别为 1.53 和 1.31。预冷 CC 和 EC 样本中方法之间的相关性分别为 0.812 和 0.880。对于所有样本类型，估计的总需氧菌数量通常大于总大肠菌群或大肠杆菌的数量（P < 2e⁻¹⁶）。与冷藏后 WCR 或累积滴线样本相比，预冷样本中回收的细菌数量明显更多（P < 9.5e⁻¹² 和 P < 2e⁻¹⁶，分别）。当排除低于检测限的样本时，在传统平板计数或 Petrifilm 方法与自动化 MPN 方法之间，有 92.1%的总响应在单个对数差异内。
