How long does breastmilk last

It seems there are a lot of differences in how long people recommend storing breastmilk. Sure, it is going to differ depending on how you store the milk. I've pulled some recommendations from multiple sources to show the variety of opinions. It is interesting as most of these recommendations are based upon different studies. I haven't had the time to dig in and understand the methods and details behind each of the recommendations.

From Kelly Mom -

HUMAN MILK STORAGE
	Temperature	Storage Time
Freshly expressed milk
Warm room	79°F / 25°C	4-6 hours
Room temperature	66-72°F / 19-22°C	10 hours
Insulated cooler /icepacks	60°F / 15°C	24 hours
Refrigerated Milk (Store at back, away from door)
Refrigerator (fresh milk)	32-39°F / 0-4°C	8 days
Refrigerator (thawed milk)	32-39°F / 0-4°C	24 hours
Frozen Milk (Do not refreeze! Store at back, away from door/sides)
Freezer compartment inside refrigerator (older-style)	Varies	2 weeks
Self-contained freezer unit of a refrigerator/freezer	Varies	3-6 months
Separate deep freeze	0°F / 19°C	6-12 months

Source: Kelly Mom - http://kellymom.com/bf/pumping/milkstorage.html

From CDC -

Location	Temperature	Duration	Comments
Countertop, table	Room temperature (up to 77°F or 25°C)	6–8 hours	Containers should be covered and kept as cool as possible; covering the container with a cool towel may keep milk cooler.
Insulated cooler bag	5-39°F or -15-4°C	24 hours	Keep ice packs in contact with milk containers at all times, limit opening cooler bag.
Refrigerator	39°F or 4°C	5 days	Store milk in the back of the main body of the refrigerator.
Freezer			Store milk toward the back of the freezer, where temperature is most constant.  Milk stored for longer durations in the ranges listed is safe, but some of the lipids in the milk undergo degradation resulting in lower quality.
Freezer compartment of a refrigerator	5°F or -15°C	2 weeks
Freezer compartment of refrigerator with separate doors	0°F or -18°C	3–6 months
Chest or upright deep freezer	-4°F or -20°C	6–12 months
Reference: Academy of Breastfeeding Medicine. (2004) Clinical Protocol Number #8: Human Milk Storage Information for Home Use for Healthy Full Term Infants.

Source: http://www.cdc.gov/breastfeeding/recommendations/handling_breastmilk.htm

From La Leche League -

Preferably, human milk should be refrigerated or chilled right after it is expressed. Acceptable guidelines for storing human milk are as follows. Store milk:
Room temperature (66-78°F, 19-26°C)	4 hours (ideal), up to 6 hours (acceptable) (Some sources use 8 hours)
Refrigerator (<39°F, <4°C)	72 hours (ideal); up to 8 days (acceptable)
Freezer (-0.4 to -4°F, -18 to -20°C)	6 months (ideal) up to 12 months (acceptable)

Source: http://www.llli.org/FAQ/milkstorage.html

From Abbott Nutrition (makers of Similac) -

Refrigerator	Use within 24 hours if possible. Discard after 72 hours.
Freezer	Up to one month in freezer compartment of refrigerator. Do not store in door of freezer.
Deep Freezer	3 - 6 months (0 F or less); store at back of freezer. Best if used within 3 months.

Source: http://abbottnutrition.com/resources/en-US/home/breastfeeding/BreastMilk%20Storage.pdf

So from these and other sources it seems that there is a range of acceptable storage times. It is interesting that a major manufacturer of formula bases their numbers on a study with some of the shortest storage times. One other good thing I've picked up is milk is probably not bad unless it smells bad or tastes sour.