BfR Annual Report 2015

BfR

Annual Report 2015

Throughout the EU it is fundamentally

prohibited by law to feed processed

animal proteins to domestic animals,

but there are exceptions to this.

Animal protein in foods and feeds

Around three million tonnes of animal byproducts from the slaughter

and production processes accrue every year in Germany. The German

meat industry generates annual sales of 30 billion euros. Animal waste

must be disposed of properly. Throughout the EU it is fundamentally

forbidden to feed processed animal proteins (PAP) to all domestic ani-

mals, from cattle to fish. In addition to this, the “anti-cannibalism” rule

stipulates that no animal species may be fed to another animal of the

same species. These rules have made a considerable contribution to-

wards gaining effective control of the lethal cattle disease BSE (bovine

spongiform encephalopathy) and minimising the number of cases.

There are exceptions to the strict feeding ban, however. Proteins from

milk and eggs that cannot be contaminated with prions, the pathogens

of BSE, as well as fish, blood and animal meals from non-ruminants

are authorised as animal feed under certain circumstances. The list of

banned products and exceptions is extremely complex and depends

on the animal species or group and the intended use.

The processing of animal proteins for feeding purposes is also strictly

regulated. The heat and pressure conditions in the prescribed process-

es severely alter the protein structure. The standard processing of ani-

mal processing requires a core temperature of 133°C and a pressure

of 3 bar for at least 20 minutes. The resultant changes in the proteins

pose great analytical challenges: is it still determinable with such highly

processed products from which animal species they originated? And

is it possible to distinguish banned PAP from approved milk powder?

Two analytical methods are currently prescribed by law in the European

Union. By using a simple light-microscopic method, it is determined

on the basis of heat-resistant particles such as hair, bone splinters or

scales, whether a feed contains any PAP at all. However, this method

cannot make a precise distinction between closely related animal spe-

cies, so that a DNA analytical method is used to detect banned rumi-

nant constitutents. This involves the detection of a ruminant-specific

gene sequence in the polymerase chain reaction (PCR). Still it is impos-

sible to distinguish between banned and authorised ruminant protein,

e. g. derived from milk or animal meal by means of PCR analysis, be-

cause ruminant DNA will be detected in both.

In the feed area, protein-based methods with which both, the animal

species as well as the tissue type can be identified, are being consid-

ered as analytical alternatives.

In the food area, the “horse meat scandal” made clear that fast in-place

methods to uncover adulterations are lacking. Antibody-based strip

tests are ideal for this purpose as they deliver a valid test result within

minutes and are very easy to handle.

Protein spots in poultry meal extracts in

a 2-D electrophoresis gel. Individual spots

are “picked” out of the gel, examined

per mass spectrometer and the proteins

identified on the basis of databases. Only

poultry-specific proteins are of benefit

to a specific detection system.