[Investigation of the Effect of Pasteurization on the Viability of Cryptosporidium parvum in Cow's Milk by Propidium Monoazide qPCR]. / Pastörizasyonun Inek Sütündeki Cryptosporidium parvum Canliligi Üzerine Etkisinin Propidium Monoazide qPCR ile Arastirilmasi.

Cow's milk, which is one of today's most important food sources, can be a reservoir for many pathogens that create a risk to public health. One of these pathogens is Cryptosporidium parvum. The oocysts of C.parvum, an obligate intracellular parasite, cause infection when ingested orally. The oocysts scattered around with the feces of infected cows or calves can contaminate raw milk and this is frequently seen in dairy farms. The aim of this study was to investigate the viability of C.parvum by propidium monoazide (PMA)-quantitative polymerase chain reaction (qPCR) method after heat treatment applied to contaminated raw cow's milk. For the study, 50 ml of unpasteurized cow's milk was contaminated with 5 X 105 C.parvum oocysts and portioned into 1.5 ml microcentrifuge tubes. Three groups, namely the control group, pasteurization group and boiling group were formed. No warming procedure was applied to the control group. In the pasteurization group, the milks in microcentrifuge tubes were poured into the wells of the dry block heater set to 71.7 °C and incubated for five seconds. At the end of the period, the milks were transferred to the wells of the cold metal tube, which was removed at -20 °C with the help of a micropipette, and incubated for five seconds. The milks in the boiling group were incubated for two minutes in a dry block heater set to 95 °C. After the heat treatment, the milks in microcentrifuge tubes were transferred to 10 ml centrifuge tubes, PBS was added to make the final volume 10 ml, and centrifuged at 4000 rpm for 20 minutes. After this process was repeated twice, 400 µl of PBS was added to the precipitate remaining at the bottom, and the precipitate was homogenized. One sample of each group was applied with PMA, while PMA was not applied to the other sample. PMA-applied samples were incubated for five minutes at room temperature and in the dark, and then exposed to UV light for five minutes in the device with cooling feature. The oocysts were collected by centrifugation at 5000 g for five minutes. After DNA isolation from oocysts, SYBR Green real time PCR (Rt-PCR) was performed using primers amplifying the COWP gene region. As a result of SYBR Green Rt-PCR, the mean Ct values of the control without PMA, pasteurization and boiling groups were determined as 25 ± 1.24, 23 ± 0.98 and 26 ± 1.03, respectively. While no peak was obtained in the boiling group after PMA application, the mean Ct values of the control and pasteurization groups were 28 ± 1.38 and 31 ± 1.46, respectively. As a result, it was concluded that live C.parvum cysts in milk could be detected by PMA-qPCR method and live oocysts could be found in pasteurized milk.

Aflatoxin M1 levels in Surk samples, a traditional Turkish cheese from southern Turkey.

In this study, aflatoxin M(1) (AFM(1)) contamination was investigated in Surk cheese, a traditional Turkish cheese consumed particularly in southern Turkey. For this purpose, 120 Surk cheese samples were collected from different retail markets and analysed by enzyme-linked immunoassay. The level of AFM(1) varied from 16 to 1,043 ng/kg in 72 of the Surk samples (60%), 16 of which (13.3% of 120 samples) contained AFM(1) amounts exceeding the maximum tolerance limit (250 ng/kg) established in Turkey. The results indicated that the occurrence of AFM(1) in Surk cheese samples may be considered as a possible risk for consumer health.

Determination of aflatoxin B(1) levels in deep-red ground pepper (isot) using immunoaffinity column combined with ELISA.

Deep-red ground pepper, a variety of red ground pepper, is a special spices belonging to Sanliurfa and consumed both in Sanliurfa and other provinces of Turkey. The aim of this study was to determine the aflatoxin B(1) (AFB(1)) levels of deep-red ground pepper. For this purpose, 75 samples of deep-red ground pepper (isot) marketed in Sanliurfa (Turkey) were purchased from bazaars and herbal shops. The occurrence and concentration range of AFB(1) in the samples were investigated by microtitre plate Enzyme Linked Immunosorbent Assay (ELISA) method using immunoaffinity columns. Seventy-two of the 75 ground deep-red pepper samples (96%) contained AFB(1) in the range of 0.11-24.7 microg/kg. Eleven (14.7%) samples were above the regulatory limits used in the European Union and in Turkey. More precaution should be taken on hygiene controls in order to prevent microbiological and chemical hazards.

The fate of two Listeria monocytogenes serotypes in "cig kofte" at different storage temperatures.

Cig kofte is a traditional Turkish food prepared from minced beef, bulgur, onions, garlic and varieties of spices. It is generally consumed within a few hours. However, leftovers can be kept in refrigerator or in room temperature up to 24h until they are consumed. In this study, survival and growth of two Listeria monocytogenes serotypes were investigated in cig kofte during the storage. For this purpose, the prepared samples were separately contaminated with serotypes 1/2b or 4b of L. monocytogenes at the level of 10(4)CFU/g and stored at 4°C and 21°C. L. monocytogenes colonies were counted at the beginning, 3rd, 6th, 12th and 24th hours of the storage. At 4°C, L. monocytogenes 4b significantly increased (P<0.05) from 4.12 to 5.49log(10)CFU/g but L. monocytogenes 1/2b remained constant (P>0.05) during the storage period. At 21°C, both L. monocytogenes 1/2b and 4b increased significantly (P<0.05) from 4.56 to 5.16log(10)CFU/g and from 4.23 to 5.65log(10)CFU/g, respectively. The physicochemical and microbiological characteristics of the cig kofte did not inhibit the growths of L. monocytogenes serotypes during the storage. These results indicated that L. monocytogenes was able to survive and grow in cig kofte at the both storage temperatures of 4°C and 21°C and cig kofte seemed to be a suitable medium for this pathogen.