Development of a potentiometric freshness sensor for estimating of bacterial spoilage in aging pork

猪肉在10℃的温度下储存。用消毒过的手术刀刮掉10克肉的表面，并用200毫升的超纯水均质。此外，超纯水的十进制稀释度分布在平板计数琼脂上，用于总的好氧活菌计数。在10℃条件下培养5d后，计数平板上的菌落总数。猪肉提取水样的pH值和NH_4~+浓度随贮藏天数的增加而增加。这可能是由于猪肉中的蛋白质被细菌和生物胺分解所致。猪肉提取水样中ORP电极的电位随保存天数的增加而降低。这也可能是因为猪肉中的蛋白质被细菌分解，并产生生物胺。而在猪肉水样中，S^2-选择电极的电位与时间无关。猪肉提取水样的pH值和活菌数随着时间的推移而增加，并与时间的推移密切相关。根据这些结果，我们得出结论，目前的传感器系统是有用的估计细菌腐败在10℃的陈化猪肉。

The pork was stored at 10℃. Ten gram of the surface part of the meat was shaved using a sterilized surgical knife and homogenized with 200ml of ultra pure water. Furthermore, decimals dilutions of the ultra pure water were spread over the plate of plate count agar for total aerobic viable counts. Colonies on the plate were counted after incubation for 5 days at 10℃ for total aerobic viable counts. Value of pH and concentration of NH_4^+ ion in pork-extracted water sample increased with the increase of the days of storage. The fact may be due to that protein in pork meat is decomposed by bacteria and biogenic amine produced. Potential of ORP electrode in pork-extracted water sample decreased with the increase of days of storage. This may be also due to that protein in pork meat is decomposed by bacteria and biogenic amine produced. However, potential of S^2-selective electrode in pork-extracted water sample is not correlated with the passage of time. The pH value of the pork-extracted water sample and viable counts increased with the passage of time and are closely correlated with the passage of time. From these results, we concluded that the present sensor system is useful for estimating the bacterial spoilage in aging pork at 10 ℃.