How is the fruit in the Goblin Market presented as delicious?

In her narrative poem Goblin Market, Christina Rossetti tells a story of two sisters tempted by fruit. It's not just any fruit: it's fruit sold by goblins in the evening at a marketplace near the girls' house, and according to Rossetti's description (and the girls' reaction to it), it's otherworldly, extra-juicy, incredibly delicious fruit. 

Let's look at some of the phrases the poet uses to describe the fruit:

Plump unpeck’d cherries, 

Melons and raspberries, 

...

In her narrative poem Goblin Market, Christina Rossetti tells a story of two sisters tempted by fruit. It's not just any fruit: it's fruit sold by goblins in the evening at a marketplace near the girls' house, and according to Rossetti's description (and the girls' reaction to it), it's otherworldly, extra-juicy, incredibly delicious fruit. 

Let's look at some of the phrases the poet uses to describe the fruit:

Plump unpeck’d cherries, 

Melons and raspberries, 

Bloom-down-cheek’d peaches, 

Swart-headed mulberries, 

Wild free-born cranberries, 

Some of the adjectives here are antiquated, but you get the sense of ripeness and fullness in words like "plump," "bloom," and "wild." Let's look at another passage from the same scene, where the goblin vendors are selling their fantastic fruit:

Our grapes fresh from the vine, 

Pomegranates full and fine, 

Dates and sharp bullaces, 

Rare pears and greengages, 

Damsons and bilberries, 

Taste them and try: 

Currants and gooseberries, 

Bright-fire-like barberries, 

Figs to fill your mouth, 

Citrons from the South, 

Sweet to tongue and sound to eye; 

Come buy, come buy.

Again, we get the feeling of ripeness and freshness, but also of abundance ("full and fine," "figs to fill your mouth.") We also understand here that the fruit isn't only ripe and tasty, it's also beautiful to look at ("bright-like-fire" and "sound to eye.") In Rossetti's description, it's both the appearance of the fruit and the taste of it that tempt the sisters.

Rossetti's appealing presentation of the fruit is only emphasized by the following scene, in which Laura tastes the fruit.

She dropp’d a tear more rare than pearl, 

Then suck’d their fruit globes fair or red: 

Sweeter than honey from the rock, 

Stronger than man-rejoicing wine, 

Clearer than water flow’d that juice; 

She never tasted such before, 

How should it cloy with length of use? 

She suck’d and suck’d and suck’d the more 

Fruits which that unknown orchard bore; 

She suck’d until her lips were sore

Needless to say, this isn't your average experience of eating a fruit salad for lunch. Laura's feasting on the fruit is practically a moment of ecstasy.