**3.4. Fungal contaminants and mycotoxins in conventional animal products**

mutagenic and genotoxic effects on living organisms. The duration of stay of pesticides in the natural environment, depend on their chemical structure. Pesticides, such as chlorinated hydrocarbons are resistant against biological degradation and they can stay in soil for years and penetrate to the food chain through various means. These fat soluble pesticides can be accumulated in the fat tissue of humans and animals as well as in their livers, kidneys and neural systems. Residues in the body of lactating animals can easily penetrate to the animal's milk [51, 52]. Contamination of animal products, such as meat and milk, with permanent pesticide residues is a frequently encountered problem. In a study conducted in Jordan, in which eggs as well as meats of chicken, sheep and cow were scanned for OCP residues, it was found that 28% of eggs, 20% of chicken meat, and 49% of red meat were contaminated with OCP [63]. Chlorinated compounds, such as PCBs, aldrin, DDT, DDD, DDE, BHC, heptachlor, etc., which enter the body of fishes through various means, can accumulate within the fishes and cause health problems in humans that consume these fishes. There is a linear relationship between accumulation of chlorinated compounds, such as PCBs, within fishes and their fat contents. The experiments showed that half-lives of PCBs in fishes are quite long. Despite the fact that utilization of PCBs was banned, they were still found in fish samples, analyzed in Ontario, Canada in

1992–1993, and in fish samples collected from 15 different countries in 1994–1995 [58].

Milk is considered sterile (free from microorganism) because of its compounds and chemical properties. But milk is a suitable medium for most microorganisms. In general, it is not expected that milk has microorganisms and toxins unless there is a systemic or local infection. But clinical and subclinical mastitis, which are associated with local or systemic infections are common problems for animals [64, 65]. The milk flora of dairy animals consists of lactic acid bacteria (LAB; *Lactococcus, Lactobacillus, Leuconostoc, Streptococcus, Enterococcus* spp.) [64]. *Staphylococcus aureus*, which produces toxins like Staphylococcal enterotoxins (SEs), SE-like toxins (SEI) and toxic shock syndrome toxin (TSST-1) and is primarily responsible for foodborne poisonings, mostly exists in milks of animals with mastitis [65]. According to State Agencies to Centers for Disease Control and Prevention and from the Center for Science in the Public Interest Database, product-based numbers of *Campylobacter*-based cases caused by consumption of raw milk, pasteurized milk and cheese that's produced from raw milk between 2000 and 2006 were recorded, respectively, as 33, 1 and 3; numbers of *E. coli*based cases were recorded, respectively, as 6, 0 and 1; numbers of *Salmonella*-based cases were recorded, respectively, as 1, 3 and 3 [66]. In a study that was made in Ankara (Turkey) with milk collected from street mostly found *S. aureus* > *E. coli* > *Klebsiella* > *Serratia* > *Proteus* [67]. In a study conducted in Czech Republic, total amount of mesophilic bacteria-TMBC (×10<sup>3</sup> CFU/ml) in conventional milk was found as 19 ± 16 (as Mean ± SD; n:1168) and amount of coliform bacteria-CBC (×10<sup>1</sup> CFU/ml) was found as 48 ± 36 (as Mean ± SD; n: 473) [21]. In low input farms in Brazil, bulk milk bacteria count (BMBC) was found higher in winter 2174 ± 958.4 (Mean ± SEM) according to other seasons. But in same season bulk tank somatic cell count (BTSCC × 1000 cells/ml) was found as 469 ± 113.4 (Mean ± SEM) [68]. In a study with raw milk in winter and summer In Slovenia, total bacteria count was found higher than

**3.3. Bacterial contaminants in conventional animal products**

100,000 cfu/ml [69].

138 Livestock Science

Mycotoxins are very toxic compounds that are produced by fungi and yeast [70]. Diseases due to the consumption of contaminated food with mycotoxins and molds are known worldwide. Grain and milk products are the most sensitive ones to contamination with mycotoxins among foods [71]. In mycotoxicosis cases, consumption of animal products (milk and dairy products, meat and meat products, egg, liver, kidney) has a major role as well as consumption of grain and grain products. Mycotoxins cause respiratory and neurological disorders, cancer, nephrotoxicity and hepatoxicity. Diseases such as Alzheimer's, multiple scleroses, etc. are considered to be related to mycotoxicosis. In pregnant women, mycotoxins that are taken with contaminated products can affect baby through placenta. Especially, infant and children are very sensitive to mycotoxins [72]. As a result of research in infant foods (rice flour, grain flour and milk powder) *Aspergillus* spp. (5%), *Penicillum* spp. (13%), *Mucor* spp. (5%) and unidentified species were isolated [71].

First mycotoxin (aflatoxin M1) contamination in dairy products was recorded in 1960s. Aflatoxin M1 (AFM1) is a metabolite of aflatoxin B1 (AFB1) and it forms in liver. 0.3–6.2% of AFB1 in animal feeds is metabolized, biotransformed, and secreted in milk in the form of AFM1. Mycotoxins such as OTA, zearalenone (ZEN), T-2 toxin and DON were also detected in milk. But these are not taken into account in importance as much as AFB1. One of the main reasons of DON and ZEN contamination is silage that is added into animal food [70]. Contamination with fungi and mycotoxin formation are not necessarily related to each other. Even when fungi contamination and variety is high mycotoxin can form less. According to a research in infant foods aflatoxin was detected only in 2.4% (19–70 μg/kg) of specimens despite of high fungus contamination [71]. In the European Union and some other countries accepted limits of AFM1 varies for raw milk is between 0.05 and 10 μg/kg, for dairy products is between 0.02 and 10 μg/kg [70].

In a study where fungal contamination variety's being analyzed of cow, goat and sheep milk, turned out that cow milk samples the highest diversity, and it was recorded that identified species were belonged to *Aspergillus, Chrysosporium, Cladosporium, Engyodontium, Fusarium, Penicillium* and *Torrubiella* genera [73]. There are less yeast and mold in raw milk than LAB [64]. In a study conducted in Slovenia, 95.0% of raw milk that was collected during winter and summer contains yeast and 63.3% contains molds. Isolated mold strains were identified as *Geotrichum* (51.5%), *Aspergillus* (33.8%), *Mucor* (5.9%), *Fusarium* (2.9%) and *Penicillium* (2.9%) genuses [69].

Poultry meat can also be contaminated by mycotoxins. A study showed that most common mold genuses are *Aspergillus* (58%) and *Penicillium*. Also, many other fungus genuses had been found with low incidence [74].

#### **3.5. Contaminants in conventional animal foods from packaging material**

Packaging is an indispensable part of the food production process. Today lots of plastics are being used as packaging material. Also, antioxidants, stabilizers, lubricants, antistatic and antiblocker materials can be used to increase the performance of package material. Additives, monomers, oligomers and contaminants can get transferred to food from packaging material. There are concerns about plasticizers (phthalates), thermal stabilizers, slip additives, light stabilizers, antioxidants, melamine, styrene, vinyl chloride, bisphenol A diglycidyl ether, isocyanate, caprolactam, polyethylene terephthalate oligomer, decomposition products, benzene and other volatiles, environmental contaminants, processing agents and other contaminants getting transferred to food [75, 76]. Studies on contamination in milk products related to this issue are limited [76].

Especially heavy metal pollution can occur in canned milk products and this is related to storage temperature and duration [77]. Also heavy metal pollution can occur during packaging process. As a result of a study, high amount of Pb was detected on bread packages [78]. In another study, high amount of Pb was detected on candy packages, which children consumed often, and this result was backed up by FDA [79, 80].

Because of that Cd got high dissolution in organic acids, human food chain's Cd pollution is very common. Studies showed that Cd, which is used for making food packages, can get transferred to high-acidic foods by getting dissolved. Wrapping foods with antimony foil, keeping in antimony containers and cooking in them causes foods get contaminated with high amount of Sb [51, 52]. Zinc can get transferred through galvanized containers to humans [56].

#### **3.6. Veterinary drug residues in conventional animal products**

Nowadays, various veterinary drugs and food additives are being used as therapeutic and prophylactic in animals. Foods of animal origin that contains drug residue consumed by human can cause allergic reactions, drug resistant microorganisms, toxicities in organs and tissue, hormonal disorders, teratogenic effects, etc. Animal originated milk and dairy products can contain veterinary drug residues as contaminants such as antimicrobials (like antibiotics), hormones, anthelmintics and pesticides. Beta-lactams, tetracyclines, aminoglycosides, macrolides and sulfonamides are the most commonly used antibiotics [81]. The result of a study made by USDA showed 5.3% of 529 carcasses have antibiotic residue. In these tests, chlortetracyclines, oxytetracyline, tetracycline, streptomycin, neomycin and erythromycin antibiotics had been detected [52]. In a study conducted in Croatia, 1259 raw milk samples were analyzed for antibiotic residue (chloramphenicol, penicillins, cephalosporins, tetracyclines, sulfonamides, beta-lactams, quinolones, aminoglycosides and macrolides) and 37 positive samples were found, but because of low levels it was stated that this would not cause any health problems [82]. The usage of chloramphenicol, which causes bone marrow suppression and aplastic anemia, is prohibited for animals. In Brazil where its usage prohibited in 1998, study made with ELISA showed 28.6% 84 raw milk samples were positive for chloramphenicol [83]. In Egypt, after antibiotic analyzes on broiler fillets, which were collected from markets, it turned out there were problems especially about detecting withdrawal times of oxytetracyline residues [84].

Steroid hormone can be in milk. Food production processes do not have any effect on milk and dairy products. Testosterone was detected in fresh cheese (0.1–0.5 mg/kg). Benzimidazole anthelmintics are being used commonly on animals thus benzimidazole anthelmintics and their metabolites (albendazole sulfoxide, albendazole sulfone, etc.) can be in dairy products [81]. The result of a study conducted in Macedonia analyzes showed only one of 55 bovine meat samples was positive for clenbuterol [85]. For preventing and curing diseases in fishes, veterinary drugs such as antibiotics mainly, anthelmintics and hormones are being used. Sometimes nonprescription or prohibited drugs can be used. In Canada, after analyzes made with sea, fresh water and canned fish, as ng/g level furazolidone metabolite 3-amino-2-oxazolidinone (AOZ), enrofloxacin, leucomalachite green, oxolinic acid and chloramphenicol residues were detected. In 28 eel samples, which were collected from markets in Tokyo, 0.07 ppm oxolinic acid was detected. Again in Tokyo, in flounder sample, which was collected from markets, 360 μg/kg oxytetracyline was detected on the skin [86].

monomers, oligomers and contaminants can get transferred to food from packaging material. There are concerns about plasticizers (phthalates), thermal stabilizers, slip additives, light stabilizers, antioxidants, melamine, styrene, vinyl chloride, bisphenol A diglycidyl ether, isocyanate, caprolactam, polyethylene terephthalate oligomer, decomposition products, benzene and other volatiles, environmental contaminants, processing agents and other contaminants getting transferred to food [75, 76]. Studies on contamination in milk products related to this

Especially heavy metal pollution can occur in canned milk products and this is related to storage temperature and duration [77]. Also heavy metal pollution can occur during packaging process. As a result of a study, high amount of Pb was detected on bread packages [78]. In another study, high amount of Pb was detected on candy packages, which children consumed

Because of that Cd got high dissolution in organic acids, human food chain's Cd pollution is very common. Studies showed that Cd, which is used for making food packages, can get transferred to high-acidic foods by getting dissolved. Wrapping foods with antimony foil, keeping in antimony containers and cooking in them causes foods get contaminated with high amount of Sb [51, 52]. Zinc can get transferred through galvanized containers to

Nowadays, various veterinary drugs and food additives are being used as therapeutic and prophylactic in animals. Foods of animal origin that contains drug residue consumed by human can cause allergic reactions, drug resistant microorganisms, toxicities in organs and tissue, hormonal disorders, teratogenic effects, etc. Animal originated milk and dairy products can contain veterinary drug residues as contaminants such as antimicrobials (like antibiotics), hormones, anthelmintics and pesticides. Beta-lactams, tetracyclines, aminoglycosides, macrolides and sulfonamides are the most commonly used antibiotics [81]. The result of a study made by USDA showed 5.3% of 529 carcasses have antibiotic residue. In these tests, chlortetracyclines, oxytetracyline, tetracycline, streptomycin, neomycin and erythromycin antibiotics had been detected [52]. In a study conducted in Croatia, 1259 raw milk samples were analyzed for antibiotic residue (chloramphenicol, penicillins, cephalosporins, tetracyclines, sulfonamides, beta-lactams, quinolones, aminoglycosides and macrolides) and 37 positive samples were found, but because of low levels it was stated that this would not cause any health problems [82]. The usage of chloramphenicol, which causes bone marrow suppression and aplastic anemia, is prohibited for animals. In Brazil where its usage prohibited in 1998, study made with ELISA showed 28.6% 84 raw milk samples were positive for chloramphenicol [83]. In Egypt, after antibiotic analyzes on broiler fillets, which were collected from markets, it turned out there were problems especially about detecting withdrawal times of

Steroid hormone can be in milk. Food production processes do not have any effect on milk and dairy products. Testosterone was detected in fresh cheese (0.1–0.5 mg/kg). Benzimidazole anthelmintics are being used commonly on animals thus benzimidazole anthelmintics and

issue are limited [76].

140 Livestock Science

humans [56].

oxytetracyline residues [84].

often, and this result was backed up by FDA [79, 80].

**3.6. Veterinary drug residues in conventional animal products**
