Pasteurization is a process of 'time @ temp', i.e., when a product reaches and is held at a particular temp for a period of time. I recently posted an example in another thread that is germane in this circumstance as well. Hamburgers, e.g., are considered safe when cooked to 155 and held for 15 seconds, or 150 for 1 minute, or 145 for 3 minutes--the reduction of bacteria is the same in each case.
Important to note: Pasteurization is not sterilization which wipes out everything. Pasteurization is meant to reduce pathogenic bacteria to safe levels (this is called a log reduction) so that the number is substantially reduced and thus unlikely to cause disease. Food is not generally sterilized because sterilization negatively affects flavors.
So, drippings in the pan are effectively pasteurized rather quickly at usual cook temps. So long as the temp of the contents of the drip pan reach or exceed minimum safe finish temps (lower temps for a longer time, usually minutes, higher temps for shorter, usually seconds) the drippings achieve an adequate log reduction in pathogenic bacteria and are safe. This also occurs when juices from one meat drip onto another below and is why, contrary to conventional wisdom, it is not unsafe to cook chicken over another meat. So long as the meat below is cooked to safe temps there is little to worry about.
While I am on the subject: As noted, effective pasteurization achieves, usually, at least a 5-log reduction in existing pathogens (the number of bacteria times .00001). It does not wipe everything out but the food is considered safe to eat, and is, if eaten within a reasonable period of time--depending on who you ask, the 2-hour or 4-hour limit rule. Pathogenic bacteria that survive will not have enough time to reproduce to unsafe levels if the food is consumed within this time period and that is the reason for the time limit. Additionally, there are some bacteria that survive cooking that produce spores. Spore production is triggered by heat and outgrowth of the spores occurs significantly, depending on the bacteria in question, at temps below 130. This is the reason for the 140 upper limit of the danger zone and is why holding food above this upper limit and, if cooking food destined to be reheated later, cooling quickly are important. If temps are allowed to drop into the zone of 70-120 (but especially 90-115) for too long significant bacterial growth can occur that reheating will not control.
Yes (removing Joe's tongue from his cheek
), when using foil and a liquid one is adding a braising phase. It can be argued that even if one isn't adding any liquid that since the meat being foiled usually releases moisture into the foil it, also, is a braising phase.
