Figures released by the Department of Agriculture and Food appear to indicate farmers have turned away from using illegal growth promoters in cattle.
The results of the 1999 National Residue Monitoring Plan show that only 15 positive samples of misuse of beta-agonists were found in a total of 38,968 tests on cattle.
The Department says the results reflect the outcome of sampling conducted in specific cases where the presence of illegal residues was suspected by Department inspectors.
A total of 47,508 tests were carried out on animals in factories and on farms, and only 16 positive samples were found in cattle.
The Department said that in 1999 approximately 90,000 samples were taken nationally from nine food-producing animal species, including aquaculture.
"In this, the second year of an expanded Residue Monitor programme, there was a continuation of the declining trend in recent years in samples testing positive for illegal residues of illegal hormones," it said.
"The overall level of positives in 1999 was 0.3 per cent compared with 0.6 per cent in 1998." The statement said that when positive results are obtained a follow-up investigation is conducted with a view to taking prosecutions.
"A significant decline in positives for inhibitory substances was revealed by extensive testing carried out during the year. Of a total of 38,000 tests, 0.7 per cent, half the previous year's level, were positive on the basis of a screening test," it said.
The Department said that its testing is being complemented by a legislatively-based regime under which the meat processors are obliged to implement approved residue monitoring measures in respect of animals supplied to them.
This system, which involves the submission to the Department by each processor of an annual residue monitoring plan, makes it mandatory in cases where animals test positive, for each processor to apply significantly increased levels of testing to subsequent consignments of animals from the suppliers in question.
"This initiative will significantly add to the protection from illegal residues afforded to consumers of Irish food products. It also enables each processor, and indeed supplier, to deal effectively and in a timely manner with any problems which might occur from time to time," it said.
The Department says the system will equip Irish processors to guarantee the quality and safety of their products to consumers.
The report says that during 1999 the courts convicted 26 people, with eight people sentenced to terms of imprisonment, and fines totalling £70,000 imposed.
Since 1996, when the final challenge to the Animal Remedies Act was rejected by the Supreme Court, a total of 188 people have been convicted of offences under animal remedies legislation.
In all, 55 people have received custodial sentences, and fines of over £600,000 have been imposed.