Johnson & Johnson, which has been beset by a seemingly endless stream of product recalls, has recalled five lots of potentially leaky insulin pump cartridges that could lead to serious health problems and death.

It also has been warned by the Food and Drug Administration over manufacturing concerns for heart devices made at its Cordis unit’s San German, Puerto Rico facility.

J&J’s Animas unit, the maker of the recalled cartridges and insulin pumps in which they are used, said in a letter to patients last month that it found some of the cartridges can leak, resulting in delivery of less insulin than intended.

Insufficient insulin can cause high blood sugar and a serious condition known as diabetic ketoacidosis, which can be fatal. A leaking cartridge could also cause the pump to fail to sound an alarm if there were blockage in the infusion set, Animas said.

The company did not immediately return calls seeking information about the specific number of recalled cartridges or whether there have been reports of harm to patients.

The affected 2.0 milliliter insulin cartridges were shipped in the United States between Nov. 30 and Jan. 4, according to the letter posted on the Animas Web site that lists the lot numbers of the recalled devices.

In addition to sending letters about the potential problem to users of its pumps, Animas said it had informed physicians and the FDA about the recall.

Separately, the FDA warned J&J’s Cordis unit in a letter sent to the company on Feb. 16 about a failure to ensure that heart devices made at the Puerto Rico plant — such as stents used to prop open arteries — were manufactured with consistency.

Specifically, inspectors found that Cordis’ procedures did not prevent abnormal products or ensure that its devices met certain specifications, according the FDA’s letter, made public Tuesday.

The FDA uncovered the problems when it inspected the plant in September and October. Although the company has since said it would take steps to address the issues, agency officials said in the letter that those steps did not work or did not go far enough.

The FDA issues dozens of such warning letters a year, though most are resolved without further action. The agency, can, however, seek penalties such as injunctions or fines.

J&J’s once-golden reputation has been badly tarnished by manufacturing and quality control problems at its plants that have led to a series of recalls of widely used consumer health care medicines, such as Tylenol, Rolaids and Motrin, and of medical devices and other products, including syringes and sutures.

The recalls, especially those of more than 250 million bottles and packages of its consumer health care products, cost J&J nearly $1 billion in lost sales in 2010 and are likely to hit revenue and earnings again this year as the company works to return affected products to pharmacy and supermarket shelves.

Shares of J&J were up 0.5 percent, at $60.70, in afternoon trading on the New York Stock Exchange.