RIO DE JANEIRO, March 24 (Xinhua) -- Brazil's JBS, the largest meat processing company in the world, has said it would shut the production of beef at 33 of its 36 plants in the country for three days.

In a statement, JBS said the decision was taken to adjust production until a decision was taken concerning the numerous countries that have closed their borders to Brazilian meat exports.

Revelations have emerged that the country's meat producers had been chemically altering meat products and selling them past their expiration date.

One of JBS' plants, belonging to its Seara subsidiary, is one of those being investigated by police.

In 2016, 40 percent of the income of JBS Mercosur, its beef unit, came from export, with a value of 11.5 billion reais (3.7 billion U.S. dollars).

The company also said that, from next week, its remaining plants would only operate at 35 percent of their production capacity.

According to Brazilian police, after a two-year investigation which culminated last week, a number of important meat companies, including JBS, "masked" rotten meat with chemical agents and bribed agricultural officials to allow their export.

The fraud ran from changing the expiration dates on meat packaging to injecting water into chicken meat to make it heavier or even using ascorbic acid to mask rotten produce.

For the moment, the Brazilian government has forbidden exports from 21 companies suspected of such acts.

Brazil is the world's largest exporter of beef and chicken, and fourth-largest of pork. In 2016, Brazilian meat exports to the world brought in around 11 billion U.S. dollars and represented 7.2 percent of all the country's exports.