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.

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Tetracyclines in Food and Feedingstuffs: From Regulation to Analytical Methods, Bacterial Resistance, and Environmental and Health Implications.

This review presents a perspective on the research trends and solutions from recent years in the domain of antimicrobial packaging materials. The antibacterial, antifungal, and antioxidant activities can be induced by the main polymer used for packaging or by addition of various components from natural agents (bacteriocins, essential oils, natural extracts, etc.) to synthetic agents, both organic and inorganic (Ag, ZnO, TiO2 nanoparticles, synthetic antibiotics etc.). The general trend for the packaging evolution is from the inert and polluting plastic waste to the antimicrobial active, biodegradable or edible, biopolymer film packaging. Like in many domains this transition is an evolution rather than a revolution, and changes are coming in small steps. Changing the public perception and industry focus on the antimicrobial packaging solutions will enhance the shelf life and provide healthier food, thus diminishing the waste of agricultural resources, but will also reduce the plastic pollution generated by humankind as most new polymers used for packaging are from renewable sources and are biodegradable. Polysaccharides (like chitosan, cellulose and derivatives, starch etc.), lipids and proteins (from vegetal or animal origin), and some other specific biopolymers (like polylactic acid or polyvinyl alcohol) have been used as single component or in blends to obtain antimicrobial packaging materials. Where the package’s antimicrobial and antioxidant activities need a larger spectrum or a boost, certain active substances are embedded, encapsulated, coated, grafted into or onto the polymeric film. This review tries to cover the latest updates on the antimicrobial packaging, edible or not, using as support traditional and new polymers, with emphasis on natural compounds.

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Biodegradable Antimicrobial Food Packaging: Trends and Perspectives

The properties of chitosan and gelatin films incorporated with ethanolic red grape seed extract and Ziziphora clinopodioides essential oil as biodegradable materials for active food packaging.

Application of carboxymethyl cellulose and chitosan coatings containing Mentha spicata essential oil in fresh strawberries.

Application an edible active coating based on chitosan- Ferulago angulata essential oil nanoemulsion to shelf life extension of Rainbow trout fillets stored at 4 °C.

The aims of the current study were to evaluate the physical, mechanical, structural, morphological, antioxidant, and antimicrobial properties of chitosan-flaxseed mucilage (CH-FM) nanofibers enriched with Ziziphora clinopodioides essential oil (ZEO; 0, 0.25, and 0.75 ml/100 ml) and sesame oil (SO; 0 and 0.75 ml/100 ml). Based on scanning electron microscopy images, the incorporation of ZEO 0.5 ml/100 ml, SO 0.75 ml/100 ml, and SO 0.75 ml/100 ml + ZEO 0.5 ml/100 ml caused an increase in the average diameters of the corresponding nanofibers. The atomic force microscopy images also showed smoother structures for nanofibers supplemented with ZEO and SO compared to the control group. The highest antimicrobial and antioxidant activities were found in CH-FM + ZEO 0.5 ml/100 ml + SO 0.75 ml/100 ml. The fabricated nanofibers had tensile strength, puncture force, puncture deformation, water vapor transmission rate, water vapor permeability, and swelling index ranging 3.52–5.55 MPa, 4.24–8.01 N, 1.15–3.45 mm, 25.01–47.49 g/m2 h, 7.98–14.08 × 10‾4 g mm/m2 h Pa, and 19.41–41.35%, respectively. Encapsulated ZEO and SO could also diffuse out slowly but durably from the nanofibers within 96 h. Our findings can give insights regarding prepared novel nanofibers containing antimicrobial/antioxidant compounds for food packaging applications.

Electrospinning of double-layer chitosan-flaxseed mucilage nanofibers for sustained release of Ziziphora clinopodioides essential oil and sesame oil

Residues of tetracycline (TC) groups were quantified in 120 broiler chickens carcasses (including breast, liver and thigh tissues) by high performance liquid chromatography (HPLC) and also four-plate test (FPT) and ELISA methods as primary screening tests. Results of FPT showed that 25% of carcasses were polluted by antibiotic residues. The ELISA assay indicated that out of 30 positive samples in FPT, 21 liver, 16 thigh and 12 breast muscle samples were positive for TC residues. Frequency of TC-like residues and their concentration ranges in ELISA-positive samples were determined by HPLC method. In comparison between the results of these methods, the correlation between FPT and HPLC (0.940) was higher than ELISA and HPLC methods (–0.726). Moreover, this study revealed that an inhibition test with a medium at pH 6 which seeded with Bacillus subtilis had highest sensitivity for detecting of TC residues.

https://www.tandfonline.com/doi/pdf/10.1080/09540105.2015.1036357

Screening, determination and confirmation of tetracycline residues in chicken tissues using four-plate test, ELISA and HPLC-UV methods: comparison between correlation results

Occurrence, seasonal variation and risk assessment of exposure to aflatoxin M1 in Iranian traditional cheeses.

Background:
Essential oils usually exhibit different
characteristics such as antimicrobial and flavoring effects. The aim of the
present study was to investigate chemical composition and in vitro
antibacterial activity of the essential oil of Ferulago angulata (Schlecht.)
Boiss aerial parts against bacterial food-borne pathogens (Staphylococcus
aureus, Bacillus subtilis, Bacillus cereus, Listeria
monocytogenes, Salmonella typhimurium and Escherichia coli
O157:H7). Methods: The chemical composition of the essential oil was
analysed by gas chromatograph coupled with mass spectrometer detector (GC-MS).
The antibacterial activity of the essential oil was assessed using broth
micro-dilution and agar disk diffusion methods. Results:
According to results of GC-MS analysis, 33 constituents were identified. The
dominant components were α-pinene (28.43%), (Z)-beta-ocimene (20.12%),
bornyl acetate (7.92%), ɣ-terpinene (5.72%), germacrene D (5.63%),
myrcene (4.67%) and p-cymene (2.17%). The results obtained in this study
showed that L. monocytogenes and B. cereus had the most
sensitivity to the essential oil (MIC and MBC= 40µg/mL; Inhibition zone: 9mm). Conclusions:
Our results indicated that F. angulata essential oil might be a
potential rich source of compounds with antibacterial properties against
food-borne bacteria.

https://ps.tbzmed.ac.ir/PDF/PHARM-21-6.pdf

Chemical Composition and In Vitro Antibacterial Activity of Ferulago angulata (Schlecht.) Boiss Essential Oil

The protein binding of tetracyclines may cause the common extraction methods are not able to completely remove them from the proteins. To overcome this problem, we introduced a simple, reliable, sensitive, and reproducible method for simultaneous clean-up and preconcentration of 4 tetracyclines in chicken meats based on two phase freezing method.

Negin Karami

Papers

Electrospinning of double-layer chitosan-flaxseed mucilage nanofibers for sustained release of Ziziphora clinopodioides essential oil and sesame oil

Screening, determination and confirmation of tetracycline residues in chicken tissues using four-plate test, ELISA and HPLC-UV methods: comparison between correlation results

Occurrence, seasonal variation and risk assessment of exposure to aflatoxin M1 in Iranian traditional cheeses.

Chemical Composition and In Vitro Antibacterial Activity of Ferulago angulata (Schlecht.) Boiss Essential Oil

Determination of tetracyclines in meat using two phases freezing extraction method and HPLC-DAD