Hellmann E, Heinrich G
Zentralbl Bakteriol Mikrobiol Hyg B Umwelthyg Krankenhaushyg Arbeitshyg Prav Med. 1985 Dec;182(1):1-16.
The psychrotrophic organism Y. enterocolitica (Y.e.) is able to grow in foodstuffs thus rendering it dangerous for the consumer. Among others, the preparation of food in the kitchen might be an important way of transmission. Not only contaminated raw meat but aswell latently infected humans and pet animals (cats, dogs) may serve as a reservoir for Y.e. contamination. After artificial contamination of UHT milk and vanilla sauce with subsequent storage at 4 degrees C, two Y.e. strains of serovars 0:3 and 0:9 carrying the virulence plasmid multiplied during the first 6 d (9 d) at a rate of 1 log/d (Fig. 1). In pasteurized milk the multiplication rate was 0,65 log/d (Fig.2). Maximum bacterial counts in UHT milk after 15 d were in the order of 10(9) CFU/ml (Fig.4). In pasteurized milk, even minimal inoculation doses of less than 5 CFU/100ml (calculated) produced multiplication of Y.e. to 1,7-27 X 10(4) CFU/ml after 7 d (Tab.1). In this case the milk has been contaminated by an appropriately diluted suspension of faeces from infected mice. When selected colonies were tested on MOX-Agar, a loss of the virulence plasmid could not be observed. In minced fresh pork meat with a bacterial count of 4,2 X 10(6) CFU/g--most of them i.e. 2,6 X 10(6) belonging to Pseudomonas sp.--added Y.e. did not multiply, but viable organisms could be recovered after contamination with only 2,9-6,6 X 10(2) CFU Y.e./g and storage at 4 degrees C for 72 h (Tab.2). Similarly, after contamination of quartered paprika husks and halves of carrots, Y.e. strains could be re-isolated after 15 d storage at 4 degrees C or room temperature if the number of bacteria used for inoculation was in the range of 10(6) (Tab.3). Feeding contaminated carrots to NMRI-mice a calculated number of 5 X 10(3) CFU Y.e./mouse were sufficient to cause infection of part of the animals together with shedding of the organisms through the faeces (Tab.4). These results support the assumption that milk and home made milk products like vanilla sauce create a risk for human health when they are stored for a few days after contamination with Y.e. carrying the virulence plasmid. The same may be true for raw minced pork and fresh vegetables but only if the initial contamination was high. This might occur during food processing procedures.(ABSTRACT TRUNCATED AT 400 WORDS)
嗜冷微生物小肠结肠炎耶尔森菌（Y.e.）能够在食品中生长，因此对消费者构成危险。其中，厨房中的食品制备可能是一种重要的传播途径。不仅受污染的生肉，而且潜伏感染的人类和宠物动物（猫、狗）都可能成为Y.e.污染的源头。在用Y.e.对超高温灭菌牛奶和香草酱进行人工污染并随后在4℃下储存后，携带毒力质粒的0:3和0:9血清型的两种Y.e.菌株在前6天（9天）以1 log/天的速率繁殖（图1）。在巴氏杀菌牛奶中，繁殖速率为0.65 log/天（图2）。15天后超高温灭菌牛奶中的最大细菌数约为10⁹ CFU/ml（图4）。在巴氏杀菌牛奶中，即使接种剂量低至每100ml少于5 CFU（计算得出），Y.e.在7天后也会繁殖至1.7 - 27×10⁴ CFU/ml（表1）。在这种情况下，牛奶被来自感染小鼠的粪便适当稀释后的悬液污染。当在MOX琼脂上对选定菌落进行检测时，未观察到毒力质粒的丢失。在细菌计数为4.2×10⁶ CFU/g的新鲜绞碎猪肉中——其中大部分即2.6×10⁶属于假单胞菌属——添加的Y.e.没有繁殖，但在用仅2.9 - 6.6×10² CFU Y.e./g进行污染并在4℃下储存72小时后，可以回收活的生物体（表2）。同样，在用Y.e.污染四等分的辣椒壳和胡萝卜半块后，如果用于接种的细菌数量在10⁶范围内，在4℃或室温下储存15天后可以重新分离出Y.e.菌株（表3）。将受污染的胡萝卜喂给NMRI小鼠，每只小鼠5×10³ CFU Y.e.的计算数量足以使部分动物感染，并导致生物体通过粪便排出（表4）。这些结果支持这样一种假设，即牛奶和像香草酱这样的自制奶制品在被携带毒力质粒的Y.e.污染后储存几天时会对人类健康造成风险。对于生的绞碎猪肉和新鲜蔬菜也可能如此，但前提是初始污染程度较高。这可能发生在食品加工过程中。（摘要截断于400字）
