Irradiation Treatment of Animal Foods

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1 Irradiatin Treatment f Animal Fds Marsida Klem PhD, Engineering Sciences Department, Alexandër Misiu University, Durres, Albania marsi_82h@yah.cm Azem Hysa MSc, Engineering Sciences Department, Alexandër Misiu University, Durres, Albania azemhysa@gmail.cm Stela Sefa MSc. Ing, Engineering Sciences Department, Alexandër Misiu University, Durres, Albania stelasefa@gmail.cm Di:1.591/ajis.215.v4n3s1p256 Abstract The presence f pathgenic micrbes in fd is a serius glbal prblem. Irradiatin, as an effective methd, destry pathgens reducing threat that cme by uncntrlled fd. In this paper we have treated irradiatin f animal fds and its effect, t decrease ttal micrbial lad n them. Fds were irradiated with a gamma irradiatr GU-3 (Cs-137 surce) with the rtatin technique. Unifrmity dse rate used was 16 % and average dse rate 4.68 Gy/min. Accrding t standards, dses used t irradiate fd varied frm t 5 kgy. Frm experimental results it was bserved that with increasing absrbed dse, ttal micrbial lad was reduced with sme rders. Variatin f lg N / N (N- ttal micrbial lad f irradiated fd and N f nn-irradiated fd) with dse, was apprximated linearly. Based n this variatin was defined D1, as the dse that cause death f abut 9 % f micrbes in fd (lg N/N= -1). D values fund experimentally had a gd crrespndence with them defined theretically (D1 = 1 / slpe ). Keywrds: gamma irradiatin, animal fd, dse, bilgical effect 1. Intrductin Public cncern abut fd safety has increased. Despite effrts t cntrl fd spilage and imprve safety, fd micrbilgical hazards still exist. Meat and pultry accunt fr a large number f fdbrne illnesses and deaths; hwever, the amunt f illness related t pathgens in prduce nw is greater (Eustice & Bruhn). Irradiatin technlgy is ne f the techniques that has aided in the reductin f harmful pathgens in a number f fds, thereby preventing illness and death caused by fdbrne illness. This technlgy, in relatin t the fd supply, is a prcess in which fd is expsed t radiant energy in quantities great enugh t cause bacteria and ther harmful micrbes t becme inactive ( Hspitals have used irradiatin fr many years t sterilize fd fr cancer patients and thers with weakened immune systems. Sme perishable fd taken int space by astrnauts is irradiated because the fd must be guaranteed free f disease-causing rganisms. ( Accrding t the Internatinal Atmic Energy Agency (IAEA), mre than 5 cuntries have apprved the use f irradiatin fr abut 5 different types f fd, and 33 are using the technlgy cmmercially ( english/prgramme/prgramme_rafs/files/ra_37_safety_f_irradiated_fd_final.pdf ). Althugh public knwledge abut irradiatin cntinues t be limited, interest in purchasing safety-enhanced irradiated fd is increasing, especially after peple receive infrmatin abut ptential benefits and risks. 256

2 2. Materials and Methds In this study were used different animal fd prducts like: fresh milk, cttage cheese, prk meat, sausages, minced and chicken meat. The weight f every prduct was 3 gram. They were packed in sterile plastic bags and were cnserved in freeze, at abut 3-4 C. Prducts were irradiated using gamma irradiatr GU-3 installed in the Institute f Applied Nuclear Physics (with Cs- 137 surce and energy.66 MeV) with the belw technique and gemetry (fig 1). Figure 1. Irradiatin technique and gemetry f fd prducts (Dimensins are given in mm) T prvide a very gd dse unifrmity (during irradiatin perid) it was used the rtatin technique f vessel with the bilgical prduct inside it. Dses used t irradiate prducts were -5 kgy. The average dse rate was P= 4.68 Gy/min and unifrmity dse rate Dmax/ Dmin = 16% (Klem & Ddbiba, 212). After irradiatin, prducts were sent in the Institute f Fd Safety and Veterinary (the nly natinal reference center in Albania fr micrbial analysis). 3. Effects f Irradiatin in Fd When micrbes present in fd are irradiated, their DNA is destryed causing defects in their genetic cde. If this defect it s nt repaired, micrbe will die r will be unable t reprduce. Effectiveness f the prcess depends n micrbe sensitivity tward irradiatin, the rate f DNA damage repair and especially by the DNA size f micrbe (Alam & Abrahem, 21), (Ahmed, 25). High sensitivity f DNA by irradiatin is because that DNA is greater than ther mlecular structures inside cell. Damage f DNA by irradiatin is caused in tw ways: 3.1 Direct way Inizatin radiatin prduce t many damages in the DNA mlecule that include the change f its base like: rupture f single and duble bnds. The main actin f this effect in the bilgical system is the rupture f DNA duble bnd like in figure

3 Figure 2. Inizatin irradiatin actin in the DNA f micrrganisms 3.2 Indirect way Indirect damage f DNA is caused by free radicals that are frmed as a result f inizatin r excitatin f water cmpnents in the cellular structure. Inizatin creates the divisin f water mlecules in hydrgen in (H+), hydrxyl (OH - ) and (O 2- ) radicals. These radicals destry and disable bacterial cmpnents like DNA, cell membranes etc (Ahmed 25), (Alam & Abrahem, 21), (IAEA Buletin, 27). 4. Results and Discussin Results btained frm analysis dne in the Institute f Fd Safety and Veterinary are given in table 1, where: Dse is the dse fr nn-irradiated prduct (cntrl); N is the number f living micrrganisms after irradiating with dse D; N is the number f living micrrganisms fr cntrl. The number f living micrrganisms it is measured in cl/g fr all the animal prducts in table 1, except the milk prduct that is measured in cl/ml. Table 1. Micrbial lad results in animal fd Animal fd prducts Fresh milk Cttage cheese Minced meat Prk meat Sausages Chicken meat D (kgy) N (cl/g) N (cl/g) Or (cl/ml) r (cl/ml) lg (N/N) < < < <

4 Frm the data table it s bserved that in the case f milk, frm the dse 1 t 2 kgy there isn t any change in the number f living micrrganisms. Similar case is bserved als fr sausages irradiated with dses 2 t 5 kgy. With data table 1 (dse D and lg N/N) are cnstructed linear regress curves fr every prduct. Figure 3. Cttage cheese prduct Figure 4. Prk meat prduct Figure 5. Minced meat prduct 259

5 Figure 6. Chicken meat prduct Figure 7. Fresh milk prduct Figure 8. Sausages prducts 26

6 Frm graphics abve it is bserved that, with increasing absrbed dse ttal micrbial lad is decreased. In many cases this decrease varies frm 1 4 cl/g fr cntrl t <1 cl/g fr irradiated prduct. Referring t (Lund et.al, 2) in many cases fr high dses it is seen a tail in graphics (fig 7, 8). Hrizntal part in the graphic indicates that with increasing dse ttal micrbial lad des nt change. Their sensitivity tward irradiatin can be defined by D1 dse value. This is the dse that makes inactive 9 % f micrrganisms in the prduct (lg N/N = -1) (Lund et.al, 2), (Nketsia-Tabiri et.al, 29). Referring t (Nketsia-Tabiri et al, 29), the equatin that calculates D1 is given by the frmula: D1 = D / lg N /N (1) Accrding t frmula (1), D1 is calculated as reciprcal slpe f linear curve: D1= -1/ slpe (2) Fr every prduct (fig 3 8) are determined experimental values f D1 (taken by crrespnding curves) and theretical values referring the abve expressin (2). It is bserved that there is a very gd accrdance between these values (table 2). Table 2. Rate f D1 (theretical)/d1 (experimental) in % Animal fd prducts D1 (theretical) kgy D1 (experimental) kgy Rate (%) Fresh milk Cttage cheese Minced meat Prk meat Sausages Chicken meat Cnclusins and Recmmendatins With increasing absrbed dse it is bserved a decrease f ttal micrbial lad. In many cases this decrease varies frm 1 4 cl/g fr cntrl t <1 cl/g fr irradiated prduct (abut 1 times). May ccur that, fr high dses appear a tail. This ne indicates that with increasing dse, ttal micrbial lad desn t change. Fr every animal prduct fd, experimental values D1 taken by respective curves with them defined theretically have a very gd accrdance. It is imprtant t apply this methd als fr dangerus pathgens t human lives. References Eustice, R. F., & Bruhn, Ch. M. Cnsumer acceptance and marketing f irradiated fds (Chapter 1), Minnesta Beef Cuncil, Minneaplis, USA. Klem, M., & Ddbiba, A. (212). Determinatin f the dse rate and sme applicatins in the GU-3 gamma irradiatr. AJTNS, N. 32, Tirane, Alam, K., & Abrahem, M. (21). Review article. Effect f irradiatin n quality f spices. Internatinal Fd Research Jurnal, 17, Ahmed, R. G. (25). Damage pattern as functin f varius types f radiatin. Medical Jurnal f Islamic Wrld, Academy f Sciences, vl. 15, n. 4, Egypt, IAEA Buletin. (27). Fd irradiatin fr fresh prduce. Applicatin f istpes and radiatin in agriculture, vl 21, n. 2/3. Lund, B. M., Baird- Parker T. C., & Guld G. W. (2). The micrbilgical safety and quality f fd, Vl.1, USA, 69. Nketsia-Tabiri, J., Adu-Gyamfi, A., & Apea Bah, F. (29). Irradiatin f prepared meals fr micrbilgical safety and shelf life extensin, IAEA, Vienna, Austria,

ESCHERICHIA COLI O157:H7

Fact Sheet N 125 July 1996 ESCHERICHIA COLI O157:H7 1. What is Escherichia cli O157:H7? Escherichia cli is a bacterium that is a cmmn inhabitant f the gut f warm blded animals, including man. Mst strains