What are the brown or black streaks the flesh of an avocado sometimes contains?

Q: What are the brown or black streaks the flesh of an avocado http://goo.gl/Gtt67x sometimes contains?
A: The "streaks" you describe occur rarely and generally in fruit from young trees. Though the fibers may be unsightly, the surrounding fruit is safe for you to eat.

Q: What does it mean if my fruit has brown/black streaks?
A: The "streaks" you describe are a relatively rare occurrence generally found in fruit from young trees. Although the fibers may be unsightly, the surrounding fruit is safe for your consumption. 

Q: Why does my avocado contain brown strings?
A: Fruit from younger trees generally tends to have strings, but these they often disappear or fade as the avocado matures. Reduced oil content in avocados also is tied to stringiness. Mid- to late-season California avocados have a high oil content, which results in fruit with little to no stringiness.

Q: What does it mean if my fruit has brown/black spots?
A: Flesh discoloration occurs when the avocado has been exposed to cold temperatures for a long period of time before it begins the ripening process. Flesh bruising can occur in transit or as a result of compression caused by excessive handling. Unfortunately there is no way to detect either flesh discoloration or flesh bruising by looking at the avocado's exterior. They are not harmful and can be removed by cutting them out.

Q: How do I know if my Hass Avocado is too ripe to eat?
A: We do not recommend eating "browned" or oxidized portions of the fruit. Overly ripe fruit can take on a rancid odor, it is best not to eat the fruit. If the fruit or guacamole has oxidized (turned brown) on the top layer and the underneath is green, simply discard the brown layer.