WASHINGTON – The Food and Drug Administration is planning to inspect all of the country’s largest egg farms before the end of next year following the massive recall that has sickened as many as 1,500 people.

An Obama administration official says inspectors will visit about 600 large egg farms that produce 80 percent of the nation’s eggs. The official spoke on condition of anonymity because the plan has not yet been announced. This will be the first government effort to inspect large egg farms, most of which have gone largely uninspected for decades.

The FDA’s plan for heightened inspections came after more than half a billion eggs linked to cases of salmonella poisoning were recalled from two Iowa farms this month. The inspections will be conducted as part of new FDA rules put in place this July to prevent salmonella in shell eggs.

The inspections will begin in September with the farms deemed highest risk to consumer safety, the official said. The new inspection plan covers all egg farms that have 50,000 or more hens.

The FDA will also be adjusting the training of the agency’s inspectors based on findings from the ongoing investigations at Iowa’s Wright County Egg and Hillandale Farms, the two farms linked to the salmonella outbreak, the official said.

The aim of the inspections, and the new egg rules, are to prevent an outbreak before it starts. In the past, the government has traditionally only inspected egg facilities, along with many other types of farms, after there is an outbreak. The FDA said it has not inspected either of the two Iowa farms despite at least one of the companies’ long history of health, safety, environmental and immigration violations.

Inspectors will be looking for safety violations that could increase the chance of salmonella entering the egg supply. They will be looking for proper refrigeration of the eggs, adherence to employee sanitation standards and any unsafe bacteria around the farms, among other things.

The rules, which also require producers to do more testing for salmonella and take other precautions, had languished for more than a decade after President Clinton first proposed that egg standards be toughened. The FDA said in July that the new safeguards could reduce the number of salmonella cases by nearly 60 percent.

Food safety advocates have pushed for such improvements in inspections for years. The FDA has traditionally focused on food manufacturing facilities instead of farms, because the agency’s authority was muddled and few standards were in place.

Those rules would be bolstered by food safety legislation passed by the House last year and pending in the Senate. The bill would provide more money to the FDA for inspections and enforcement.