Antibiotics in meat

Antibiotics are used by meat producers to improve animal production and treat disease. These are administered to beef and dairy cattle, swine, broiler chicks and laying hens. 16 Prophylactic antibiotics are also widely administered in finfish aquaculture to prevent bacterial infections that result from poor sanitation in fish farming. 17  

The administering of antibiotics to animals and fish leads to the accumulation of residues in the animals flesh and subsequent ingestion by humans. 

The effects on humans following consumption of meats with antibiotic residues have not been well studied. It is surmised that such residues help lead to antibiotic-resistant bacteria with obvious human end points. 

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There is an additional protection against residues, because antibiotics in meat tend to be destroyed by cooking.. For example, Broquist and Kohler found that chicken breast muscle containing 12 parts per million of chlortetracycline had 0.14 parts per million after roasting at 230 C for 15 minutes and no detectable amounts after half an hour. The original level of 12 ppm was about 60 times as high as would be produced by 400 ppm in the animal feed, without a withdrawal period W. The UK Swann Committee reported that the only possible effect of residues on consumers arose from penicillin in milk from cows treated for udder infections in which the withdrawal time for the antibiotic had not been observed. Cases of skin rashes were reported from the consumption of such milk by sensitive patients. The Committee commented that "there are no known instances in which harmful effects in human beings have resulted from antibiotic residues in food other than milk" ( ) ... 

The emergence of microbial antibiotic drug resistance was speeded by the indiscriminate use of antibiotics in humans and livestock. Exposure to very low concentrations of antibiotic in meat or milk may have provided a path whereby human pathogens could eventually evolve high-level antibiotic drug resistance. Recently some strains of enterococcus and tuberculosis have developed resistance to all known antibiotic drugs. Inappropriate use of antibiotics is very common, and it accelerates the development of resistance in pathogens. 

DG Kennedy, RJ McCracken, A Cannavan, SA Kewitt. Use of liquid chromatography-mass spectrometry in the analysis of residue antibiotics in meat and milk. J Chromatogr 812 77-98, 1998. 

M Horie, K Saito, R Ishii, T Yoshida, Y Haramaki, H Nakazawa. Simultaneous determination of five macrolide antibiotics in meat by high-performance liquid chromatography. J Chromatogr A 812 295-302, 1998. 

M. Horie, H. Takegami, K. Toya, H. Nakazawa, Determination of macrolide antibiotics in meat andfish by LC-ESI-MS, Anal. Chim. Acta, 492 (2003) 187. 

Another current trend that is well underway is the use of more specific analytical instrumentation that allows less extensive sample preparation. The development of mass spectrometric techniques, particularly tandem MS linked to a HPLC or flow injection system, has allowed the specific and sensitive analysis of simple extracts of biological samples (68,70-72). A similar HPLC with UV detection would require significantly more extensive sample preparation effort and, importantly, more method development time. Currently, the bulk of the HPLC-MS efforts have been applied to the analysis of drugs and metabolites in biological samples. Kristiansen et al. (73) have also applied flow-injection tandem mass spectrometry to measure sulfonamide antibiotics in meat and blood using a very simple ethyl acetate extraction step. This important technique will surely find many more applications in the future. 

Horie, M., Takegami, H., Toya, K., and Nakazawa, H. (2003) Determination of macrolide antibiotics in meat and fish by liquid chromatography-electrospray mass spectrometry. Analytica Chimica Acta 492,187-197. 

Veterinary Applications. Another use for antibiotics is for veterinary appHcations and for animal feed supplements to promote growth in Hvestock (see Feeds and feed additives). Feed antibiotics used in the United States far surpass all other agricultural appHcations in terms of kilogram quantities used and approach quantities used in human medicines (25). In 1980 the USA feed antibiotic usage was estimated to be between five and six million kg. The U.S. Council of Agricultural Science and Technology estimates that feed additives save the U.S. consumer approximately 3500 million per year in meat prices, and antibiotic use accounts for most of this. 

In order to prevent veterinary dmgs from being transported to the human food chain, radioisotopic immunoassays were developed to monitor veterinary antibiotics such as penicillin and chloramphenicol [56-75-7] C22H22Cl2N20, in meat, milk, and eggs (qv) (see ANTIBIOTICS Meatproducts Milk AND MILKPRODUCTS). 

Chloramphenicol (CAP) is a broad-spectrum antibiotic that was widely used in veterinary medicine. Since 1994 the use of CAP is banned in the EU because of certain toxicological problems (i.e., aplastic anemia and the grey baby syndrome ) observed in its administration to humans [ 107] that have prompted the establishment of a zero tolerance for the presence of these residues in meat and animal products. As a consequence, many efforts have been made to develop sensitive methodologies capable of detecting CAP residues or its metabolites. 

Franco, D., Webb, J. and C. E. Taylor (1990). Antibiotic and Sulfonamide Residues in Meat Implications for Human Health. Journal of Food Protection 53 (2) 178-185. 

This overview has presented an introduction to the subject of antibiotics in animal agriculture and provides a general view of the extent of antibiotic use. The manuscripts to follow will offer more details and provide additional food for thought. Certainly the current efficient production of meat and dairy products is dependent on a wide variety of antibiotics and this will continue to be true in most Western countries in which livestock production is an important part of the economy. 

Residual antibiotics. With the widespread use of antibiotics in feeds the occurrence of residuals in milk, meat and eggs becomes inevitable. These residuals result primarily from failure by the producer to adhere to adequate withdrawal periods following the use of the antibiotics. In a review by Katz ( ), residual antibiotics were found in all animal species marketed in 1976 - 1978. 

Since about 1952, the American public has been amply supplied with meat produced largely from animals that received feed containing antibiotics. These and other chemicals, including sulfonamides and antiparasitic drugs such as anthelmintics and coccidiostats added to feed, have saved labor, feed and space, thus revolutionizing animal agriculture. The record of safety of antibiotics in animal feed in the US has been excellent, including safety to producers and meat handlers as well as to consumers. 

In the decade of the 1950s, the use of antibiotics in animal feeds led to improvements in animal health and animal production. This contributed to the rise of large units for maintaining meat animals and poultry. These first 10 years should have given ample time for resistant pathogens to have become widespread. Ten years of this spread of resistance ought to have made antibiotics in animal feed useless or deleterious so that their commercial use would cease. Yet this has not happened, even after 35 years. The failure of such a series of events to take place is an unexplained riddle. 

The committee recommended a comparison of subtherapeutic with therapeutic use of antibiotics on the prevalence of resistant transfer factors in meat animals. Also recommended was a study comparing the enteric flora of vegetarians and meat-eaters. A third study would involve workers in abattoirs and their contacts. These studies are in progress under the direction of Dr. Edward Kass at Harvard University and investigators at the Loma Linda Medical School. The committee also recommended further research on the mechanisms of the antibiotic growth effect. The report (7) said there is little indication that sale of antibiotics, including penicillin and tetracyclines, for feed and veterinary use, "has decreased as a result of the Swann Report."... 

Consumer Reports, March 1985, warned against "licking your fingers while eating raw meat" and said that the findings by Holmberg "appear to pull the rug out from under" those who had claimed there was no link between antibiotics in feed and human disease. The "hundreds of thousands of cases" are not... 

The Food Safety and Inspection Service (FSIS) of the United States Department of Agriculture (USDA) is responsible for providing meat and poultry products to the consumer that are safe, wholesome, and unadulterated. Before marketing, meat animals and poultry must be properly withdrawn from antibiotics to ensure that the levels of antibiotics in edible tissues at slaughter are at or below the tolerances established by the Food and Drug Administration (FDA), FDA is responsible for the approval and regulation of animal drugs used in animal husbandry in the USA,... 

FSIS currently uses a variety of tests for detecting antibiotic residues in meat among these are field, in-plant, and laboratory screen tests, bioassays, immunoassays, and related biochemical techniques. 

Other tests used by FSIS to detect, identify, and/or quantify antibiotic residues in meat are primarily designed for laboratory use. 

Antibiotic use in meat production, extent of agricultural use, 5 Antibiotics... 

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