Some of the U.K’s top canine detectives could be in the doghouse after a report found that they failed to collar a single class A drug over a seven-month period, but did successfully sniff out cheese and sausages packed inside travelers’ suitcases on numerous occasions.

In fairness to the four-legged border guardians, they were only doing what they were trained to do, as certain food items – including all meat and dairy from outside the EU – are banned from being brought into the U.K. However, given the disproportionate quantities of harmless treats being detected, officials are worried that sniffer dogs are being deployed in ways that are too “predictable,” making it easy for real smugglers to slip through the net.

The findings are part of a wider report into border controls at Manchester Airport, the third-largest airport in the U.K. and a major travel hub for northern England, Scotland, and Northern Ireland. The airport employs the olfactory expertise of six trained sniffer dogs – with another "apprentice" currently in training – housed at a recently-built kennel, constructed in 2010 at a cost of £1.25 million ($1.77 million).

According to the report, drugs like heroin and cocaine are considered a “very high priority” for customs officials at the airport, yet the fact the dogs failed to get a lead on a single package of these substances between November 2014 and June 2015 has led to calls for a review of the ways in which they are used.

The cheese-loving pooches did at least make some busts over this period, helping the authorities seize 181 kilograms (400 pounds) of illegal meat, as well as £28,000 ($40,000) in cash and almost 50,000 cigarettes. They also got their paws on three parcels of class B drugs, and an assortment of other pills including Viagra.

Much of the illegal foodstuffs found by the dogs were, however, nothing but harmless picnic fare brought back by travellers who were unaware of the government’s campaign against non-European sandwich fillings. The report claims that these items pose “minimal risk to U.K. public health,” and recommends that dog handlers “target flights where the dog might detect ‘bushmeat’.”

This refers to meat from wild animals – including mammals, birds, and reptiles – which could potentially harbour microbes that pose a risk to public health in the U.K. Border Force, the government department in charge of securing the country’s borders, says it will now act on the report’s recommendations and make changes to the ways in which it deploys its canines.

It is not yet known if any of them will lose their jobs, although, with the sniffers under fire for seeking out too many sausages, there could be a lot of hot dogs at Manchester airport.