The Torah allows the eating of pork

11:1 And the LORD spake unto Moses and to Aaron, saying unto them,

11:2 Speak unto the children of Israel, saying, These are the beasts which ye shall eat among all the beasts that are on the earth.

11:3 Whatsoever parteth the hoof, and is clovenfooted, and cheweth the cud, among the beasts, that shall ye eat.
11:4 Nevertheless these shall ye not eat of them that chew the cud, or of them that divide the hoof: as the camel, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.
11:5 And the coney, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.
11:6 And the hare, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.
11:7 And the swine, though he divide the hoof, and be clovenfooted, yet he cheweth not the cud; he is unclean to you.
11:8 Of their flesh shall ye not eat, and their carcase shall ye not touch; they are unclean to you.

And the swine, though he divide the hoof, and be clovenfooted

Cud is a portion of food that returns from a ruminant's stomach to the mouth to be chewed for the second time. 

Ruminants are mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The process, which takes place in the front part of the digestive system and therefore is called foregut fermentation, typically requires the fermented ingesta (known as cud) to be regurgitated and chewed again. The process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination.[1][2] The word "ruminant" comes from the Latin ruminare, which means "to chew over again".

Monogastric herbivores, such as rhinoceroses, horses, and rabbits, are not ruminants, as they have a simple single-chambered stomach.

Large Blacks are best suited for pasture-based farming due to their strong foraging and grazing ability

So, for an animal to be acceptable, they have to 

A. have cloven hooves, and

B. chew cud

A. is automatically satisfied for pigs, it specifically says

And the swine, though he divide the hoof, and be clovenfooted

So all I need to do here is satisfy B., that pigs chew cud by the definition of the Torah. Unfortunately, pigs aren't ruminants

11:5 And the coney, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.

11:6 And the hare, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.

And there just so happens that there are pigs that eat grass.

They're called Large Black Hogs, a heritage breed that can live off pasture.

Although pigs have cloven hooves, the dispute is if they eat cud.  There are different definitions of what counts as cud.  The Jewish religion says it's grass.  Wiki said it's pre eaten food.  I would say the Jewish definition is the more relevant one to this for 2 reasons:

1) It's their religion.  They defined the word as grass eating, so it's their definition that works.

2) In those days, pig anatomy wasn't the best, so the people then I don't even think knew that a pig had 2 stomachs for consuming food separately.  It was before Christ in those days, days before people knew how a Pig's digestive system worked since the internet kindof wasn't a thing back then, so I don't think they knew Didly Squat about pig anatomy and functions back then.  

https://livestockconservancy.org/index.php/heritage/internal/largeblack states that Large Black Hogs aren't from Israel, but are from England, so the Torah wasn't talking about them. 

Also, where is the source for your quote?