Fruit <keeps><will keep> longer in the fridge

In one of its definitions of 'will', Cambridge Dictionary(Cambridge Dictionary | English Dictionary, Translations & Thesaurus) says:

will is used when referring to something that always or usually happens, and then it gives a good number of examples.

Now consider these two sentences, please:

a) Fruit will keep longer in the fridge.

b) Fruit keeps longer in the fridge.

My questions are:

1) What is the difference between a) and b)? Why 'will' in a)?

2) Can I put can and may in the place of will in a)?

3) I don't think we could replace will with could or might in a). Am I right?

• (1b) Fruit keeps longer in the fridge is a general statement of a universal (under normal circumstances) fact, a middlle voice usage. cf Ice melts at 273K.
• (1a) Fruit will keep longer in the fridge may be used as a replacement for (1b) with precisely the same meaning, or as a mild incentive/corrective to someone leaving it out of the fridge.

...........

• (2a/b) Fruit can/may keep longer in the fridge are both grammatical, but have different default meanings from (1), 'Sometimes, ...' or 'It's possible that ...', and are best avoided. Occasionally, one might hear the variant with 'can' used with the intended meaning of (1[a]). This isn't strictly wrong (modals are notoriously polysemous), and context would disambiguate.

...........

• (3a/b) Fruit could/would keep longer in the fridge are again both grammatical, but again have different default senses from (1[a]). They involve correction, with perhaps sarcasm.