Antibiotics are widely used as growth promoters in animal husbandry; among them, the tetracyclines are a chemical group of relevance, due to their wide use in agriculture, surpassing in quantities applied almost every other antibiotic family. Seeing the considerable amounts of tetracyclines used worldwide, monitoring of these antibiotics is paramount. Advances must be made in the analysis of antibiotics to assess correct usage and dosage of tetracyclines in food and feedstuffs and possible residues in pertinent environmental samples. The tetracyclines are still considered a clinically relevant group of antibiotics, though dissemination of tolerance and resistance determinants have limited their use. This review focuses on four different aspects: (i) tetracyclines, usage, dosages, and regulatory issues that govern their food-related application, with particular attention to the prohibitions and restrictions that several countries have enforced in recent years by agencies from both the United States and the European Union, (ii) analytical methods for tetracyclines, determination, and residues thereof in feedstuffs and related matrices with an emphasis on the most relevant and novel techniques, including both screening and confirmatory methods, (iii) tetracycline resistance and tetracycline-resistant bacteria in feedstuff, and (iv) environmental and health risks accompanying the use of tetracyclines in animal nutrition. In the last two cases, we discuss the more relevant undesirable effects that tetracyclines exert over bacterial communities and nontarget species including unwanted effects in farmers.

Relevant epidemiological information is provided in this report for Salmonella based on data obtained from a Costa Rican surveillance program for animal feeds. In addition to prevalence, a description in terms of serotypes and tetracycline (TET) resistance of the isolates is included. A total of 1725 feed and feed ingredients samples were analyzed during 2009 and 2014, from which 110 Salmonella strains were recovered (76 from poultry, 23 from meat and bone meal [MBM], 3 from pet foods, and 8 from other feed). Retrieved isolates were serotyped and tested for minimum inhibitory concentration (MIC) against TET. Salmonella strains were found mainly from poultry feed (different growth stages, n = 76/110; 69.1%) and MBM (n = 23/109; 21.1%). The rest of the isolates were recovered from feather meal, pet food, fish meal (n = 3/110; 2.3% each) and swine feed (n = 1/110; 0.9%). From the different serotypes recovered (n = 21), the most common were Salmonella Give (n = 18; 13.8%) and Salmonella Rissen (n = 6; 4.6%) for MBM and Salmonella Havana (n = 14; 10.8%), Salmonella Rissen, Salmonella Soerenga, and Salmonella Schwarzengrund (n = 8; 6.2% each) in poultry feed. Recovered strains were regarded to be sensitive or have an intermediate resistance to TET as evidenced by their MIC50 and MIC90 concentrations of 4 and 8 μg/mL for MBM and poultry feed, respectively. Compound feed and MBM samples exhibited strains characterized by 86.8 and 88.9% of the isolates classified (according to CLSI, 2015 ) as sensitive, 7.7 and 3.7% as intermediate, and 5.5% (with >256 μg/mL as the highest concentration) and 7.4% (with 64 μg/mL as the highest concentration) as resistant to TET, respectively. Salmonella serovars Anatum and Havana exhibited the highest resistance profile >256 and 128 μg/mL, respectively. Hence, MBM and poultry feed seem to be a target of interest if Salmonella incidence is to be controlled. Serotypes recovered have in the past demonstrated pathogenic capability; therefore, hereafter a stricter surveillance program may be in order.

Aflatoxins are toxic fungal metabolites, which can be found in feed. Aflatoxin M1 (AFM1) is excreted into milk when ruminants ingest aflatoxin B1 contaminated feedstuffs. Due to its carcinogenic potential, contamination of milk and dairy products with AFM1 may pose a risk for consumers. Hence, it is considered a public health concern. In this survey, the level of AFM1 contamination of dairy products marketed in Costa Rica was determined by enzyme-assisted extraction, immunoaffinity clean-up and high-performance liquid chromatography coupled with a fluorescent detector (HPLC-FLD) in fluid milk (n = 70), fresh cheese (n = 70) and sour cream (n = 70) collected at local convenience stores and supermarkets. AFM1 concentrations in milk and fresh cheese ranged from 19 to 629 ng/L and from 31 to 276 ng/L, with mean values of 136 ng/L and 74 ng/L, respectively, whereas none of the sour cream samples analysed tested positive for this aflatoxin. In 30 milk samples, and 10 cheese samples, AFM1 concentrations surpassed threshold concentrations as established by the European Commission. Thus, sour cream and - to a lesser extent - cheese manufacturing seems to reduce the amount of AFM1 present in milk, possibly due to fraction redistribution or microbiological degradation. The survey results reveal improper quality control procedures in the Costa Rican dairy industry. Therefore, a surveillance programme for dairy products in our country is recommended.

Food and feed laboratories share several similarities when facing the implementation of liquid-chromatographic analysis. Using the experience acquired over the years, through application chemistry in food and feed research, selected analytes of relevance for both areas were discussed. This review focused on the common obstacles and peculiarities that each analyte offers (during the sample treatment or the chromatographic separation) throughout the implementation of said methods. A brief description of the techniques which we considered to be more pertinent, commonly used to assay such analytes is provided, including approaches using commonly available detectors (especially in starter labs) as well as mass detection. This manuscript consists of three sections: feed analysis (as the start of the food chain); food destined for human consumption determinations (the end of the food chain); and finally, assays shared by either matrices or laboratories. Analytes discussed consist of both those considered undesirable substances, contaminants, additives, and those related to nutritional quality. Our review is comprised of the examination of polyphenols, capsaicinoids, theobromine and caffeine, cholesterol, mycotoxins, antibiotics, amino acids, triphenylmethane dyes, nitrates/nitrites, ethanol soluble carbohydrates/sugars, organic acids, carotenoids, hydro and liposoluble vitamins. All analytes are currently assayed in our laboratories.

Although tetracyclines and macrolides are common additives for animal nutrition, methods for their simultaneous determination in animal feeds are nonexistent. By coupling an organic extraction and solid-phase extraction cleanup to a high-performance liquid chromatography separation and a nonaqueous postcolumn derivatization, we succeeded in detecting from 0.2 to 24.0 μg kg–1 of tetracycline, oxytetracycline, chlortetracycline, doxycycline, tigecycline, and 4-epitetracycline in this complex and heterogeneous matrix. Minocycline and tylosin could also be detected with our procedure, but using UV spectrophotometry (1.5 ≤ LOD ≤ 1.9 mg kg–1). Linear responses with correlation coefficients between 0.996 and 0.999 were obtained for all analytes in the 0.5–10 mg kg–1 concentration range. Average recoveries between 59 and 97% and between 98 and 102% were obtained for the tetracyclines and tylosin, respectively. Replicate standard deviations were typically below 5%. When this method was applied to 20 feeds marketed in Costa Rica, we detected labeling inconsistencies, banned mixtures of tetracyclines, and tetracycline concentrations that contravene international regulation.

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Animal by-product rendering establishments are still relevant industries worldwide. Animal by-product meal safety is paramount to protect feed, animals, and the rest of the food chain from unwanted contamination. As microbiological contamination may arise from inadequate processing of slaughterhouse waste and deficiencies in good manufacturing practices within the rendering facilities, we conducted an overall establishment's inspection, including the product in several parts of the process.An evaluation of the Good Manufacturing Practices (GMP) was carried out, which included the location and access (i.e., admission) to the facilities, integrated pest management programs, physical condition of the facilities (e.g., infrastructure), equipments, vehicles and transportation, as well as critical control points (i.e., particle size and temperature set at 50 mm, 133°C at atmospheric pressure for 20 min, respectively) recommended by the OIE and the European Commission. The most sensitive points according to the evaluation are physical structure of the facilities (avg 42.2%), access to the facilities (avg 48.6%), and cleaning procedures (avg 51.4%).Also, indicator microorganisms (Salmonella spp., Clostridium spp., total coliforms, E. coli, E. coli O157:H7) were used to evaluate the safety in different parts of the animal meal production process. There was a prevalence of Salmonella spp. of 12.9, 14.3, and 33.3% in Meat and Bone Meal (MBM), poultry by-products, and fish meal, respectively. However, there were no significant differences (P = 0.73) in the prevalence between the different animal meals, according to the data collected.It was also observed that renderings associated with the poultry industry (i.e., 92.0%) obtained the best ratings overall, which reflects a satisfactory development of this sector and the integration of its production system as a whole.

Background: When present in animal feedstuff, mycotoxins contaminants and antibiotic residues can have negative implications for animal production and Public Health, including the transmission of carcinogenic compounds and the selection of antibiotic resistant bacteria, respectively. So far there are no available methods in which both mycotoxins and antibiotic residues are analyzed using a parallel extraction approach. To address this issue, we developed a LC/MS methodology with high sensitivity (0.005 to 6.42 and 24.55 to 132.73 μg kg − 1 for mycotoxins and antimicrobials) and specificity (unique target ion mass/charge) that allows the detection of 26 mycotoxins and 23 antibiotic residues in animal feedstuff and validated it through the determination of these analytes in 294 animal feed and feed ingredient samples in the framework of a country-wide surveillance program. Two hundred and five of these samples were analyzed for mycotoxins and 89 for antibiotics. Findings: Fumonisin was the most frequently toxin found, with FB 1 and FB 2 presenting prevalences of 50 and 52% and maximum concentrations of 14,927.61 and 8646.67 μg kg − 1 , respectively. Other toxins, including diacetoxyscirpenol n = 4/101 (3.96%), fusarenon-X n = 2/101 (1.98%), citrinin n = 2 (1.98%), and patulin n = 1 (0.99%) were rarely found. Toxicologically relevant concentrations of toxin metabolites, such as HT-2 (6.38-485.49 μg kg − 1) and 3−/15acetoxydeoxynivalenol (877.89-3236.56/5.44-1685.3 μg kg − 1), were also found. Few samples exceeded threshold mycotoxin concentrations defined in current EU guidelines. Dairy cattle and swine feeds included the higher number of samples exceeding guideline values (n = 6 and n = 5, respectively). From the total of samples analysed for antibiotics, 7.7% (n = 7/89) were classified as medicated for poultry and pigs. Unexpectedly, 57% of these medicated samples contained no detectable antibiotics (n = 4/7). The remaining 43% of the samples (n = 3/7) presented inconsistencies regarding the concentration of analytes declared on the labels or the antibiotics found. Likewise 74.6% (n = 50/67) of the non-medicated feed samples analyzed had antibiotic residues. Additionally, we analyzed commercial monensin standards for purity and evaluate batch-to-batch flushing feed industry practices. Conclusions: Herein we report the results for a year-wide analysis for mycotoxins and antibiotics in feed samples. Mycotoxins, several metabolites, and the occurrence of these emerging contaminants were evaluated and antibiotic residues in non-medicated feed samples were found using a targeted MS-based LC approach. This validated multianalyte method is expected to facilitate the monitoring and surveillance of contaminants, from natural and anthropogenic origin, in animal feed.