Kadir Halkman

• Ankara University

Nowadays, as consumers tend to avoid foods containing synthetic preservatives, technologically processed plant extracts can be a good alternative to these preservatives. In this study, previously obtained basil essential oil microcapsules (BEOM) were added to mayonnaise in order to produce a microbiologically safe product with improved physicochemi...

Bu çalışmada zeytin yaprağı ekstraktı, greyfurt uçucu yağı, portakal kabuğu uçucu yağı, biberiye uçucu yağı ve propolisin, tek başına ve kombinasyonlar halinde E. coli O157:H7, S. Enteritidis, E. coli Biyotip 1, L. monocytogenes ve S. aureus’a karşı antibakteriyel aktiviteleri disk difüzyon yöntemiyle araştırılmıştır. Patojenlere karşı en yüksek in...

This study aimed to develop an effective decontamination process for whole yellow and white onions with maintained quality attributes. For this purpose, a far infrared radiation (FIR) process was evaluated to determine its effects on microbial safety and quality of the onions. Prior to the FIR process, samples were inoculated with Salmonella cultur...

Gıdalarda Bacillus cereus kaynaklı hastalıklarda bakterinin sporlanması ve germinasyonu önemlidir. Bakteriler, yaşamsal bir tehdit altında olduklarında spor oluştururlar ve koşullar normale döndüğünde çimlenerek yaşamlarına devam ederler. Gıdanın bileşimi de sporlanma üzerinde etkilidir. Bu çalışmada, literatürde rastlanan 8 farklı besiyeri kullanı...

The aim of this study was to evaluate the behaviour of Salmonella Enteritidis during the storage of yoghurt at different temperatures (4, 12, 20, and 25 °C), and to develop mathematical models to predict the behaviour of this bacterium as a function of storage temperature. Results indicated that Salmonella was able to survive longer during storage...

The objective of this study was to evaluate the behavior of Salmonella Enteritidis and Salmonella Typhimurium, the two most important serovars of salmonellosis, during the fermentation of yogurt. The microorganisms were enumerated in milk throughout the fermentation process at three initial inoculum levels (3, 5 and 7 log CFU/mL). DMFit software wa...

Bu çalışmada, gıdalarda Salmonella aranması amacıyla, önzenginleştirme aşamasında ISO tarafından önerilen tamponlanmış peptonlu su ile FDA tarafından kimi gıdaların analizi için önerilen laktoz broth, S. Enteritidis ATCC 13076 ve S. Typhimurium ATCC 13311 olmak üzere iki farklı Salmonella serotipi için denenmiştir. Çalışmada, refakatçi flora olarak...

Yoğurt düşük pH (pH 4.2-4.5) içeriği ile mikrobiyolojik açıdan genellikle güvenilir gıda olarak düşünülmektedir. Diğer taraftan Salmonella spp. süt ürünleri tüketimi ile ilişkili hastalıkların en sık nedeni olarak gösterilmektedir. Bu çalışmada geleneksel yoğurt kültürü kullanılarak yapılan yoğurtlarda, Salmonella Enteritidis’in süte fermantasyon ö...

Shell eggs from healthy chickens are assumed sterile inside, but numerous microorganisms might be present on the shell. While warm water and controlled microwave applications are some common whole egg pasteurization processes, surface decontamination might be a feasible process since majority of microorganisms are located over the shell. With infra...

zet Bu çalışmada önceki ISO standardında (ISO 9308-1:2000) belirtilen UV destekli indol esaslı hızlı E. coli testi ile Bactident E. coli testi (MUG esaslı hızlı test) karşılaştınlmıştır. Bu amaçla çeşitli gıda örneklerinden izole edilen ve tanısı yapılmış olan 46 adet E. coli izolatı, 4 referans E. coli suşu ile koliform grup bakterilerin geliştiri...

This study aims to find out the relevance of enzymes and compare them with all identification tests of S. aureus. Staphylococcus aureus ATCC 6538 and ATCC 25923 were used as control strains and 54 typical colonies at BPA which were isolated from 39 raw milk and 15 white cheese samples were analyzed in terms of lecithinase, potassium telluride degra...

Rapid and accurate identification of P seudomonas species, especially in drinking water, is of great importance for human health. In the present study, we aim to develop a fast and reliable verification method, which does not require intensive microbiological procedures. In this method, specific R aman spectra of P seudomonas aeruginosa , P seudomo...

In this study, lactobacilli, yeast and coliform bacteria analyses were conducted for tomato paste, ketchup, mayonnaise and pizza sauce, by a prototype system which was developed using Durham tube. For this purpose, gas production time in Durham tube for intentionally contaminated foodstuffs were determined and comparing these values with the colony...

Listeria monocytogenes is an important food-borne pathogen and is widely tested in food, environmental and clinical samples. In this study, 50 food samples were analyzed for the presence of Listeria spp. through Singlepath® Listeria rapid test after selective enrichment stages. Moreover, following the pre-enrichment and selective enrichment stages...

This study aimed to determine the time taken for Escherichia coli O157:H7 to adapt to different types of acids and the effect of acid adaptation on the survival level of E. coli O157:H7 in sucuk (Turkish-type fermented sausage). E. coli O157:H7 cells were adapted to acids in a tryptic soy broth (TSB) set to pH 5.5 for 1-, 2-, 3-, and 4-h periods us...

Enterococci are normal inhabitants of the gastrointestinal tract and can be used as fecal indicators. The beneficial role of enterococci in the dairy and meat industry, especially during ripening of traditional cheeses and sausages, is to favor the development of sensory characteristics due to lipolytic activity, citrate utilization, and the produc...

Microwaves are used in the food industry and most of their effect is attributed to thermal processes. There is, however, some evidence to suggest nonthermal effects induced by treatment with microwaves. The thermal effect of microwave radiation is related to the heat generated by the absorption of microwave energy by water and organic molecules, bu...

GAP (Good Agricultural Practice) and EUREPGAP (Euro Retailer Produce Working Group; Good Agriculture Practice) is mainly the part of HACCP; both are applied at whole world, including South-east Asia and Africa. Although GAP and also EUREPGAP is not directed to prevention of mycotoxin formation, the total food safety concept as from farm to table; w...

The inhibitory effect of alcohol extract of sumac (Rhus coriaria L.) was investigated at concentrations of 0.1, 0.5, 1.0, 2.5 and 5.0% (w/v) on the growth of 12 bacterial strains (6 Gram positives and 6 Gram negatives), mostly foodborne including pathogens. Minimal inhibitory concentration of the spice for each test organism was also studied by obs...

The antimicrobial effect of water extracts of sumac (Rhus coriaria L.) at concentrations of 0.1%, 0.5%, 1.0%, 2.5% and 5.0% (w/v), non-neutralized and after neutralization to pH 7.2+/-0.1, was studied on the growth of 12 bacterial strains (six Gram positive strains and six Gram negative strains), mostly food borne including pathogens. It was found...

To improve enrichment and isolation of Escherichia coli O157:H7, this study evaluated increased incubation temperature and cefixime-tellurite (CT) on five strains of each of the following bacteria, E. coli, Hafnia alvei, Enterobacter spp., Citrobacter freundii and E. coli O157:H7, and two strains of E. coli O157:nH7. These were grown in pure cultur...

For much of the twentieth century, coliform bacteria and especially Escherichia coli have been used as indicators of possible post-processing contamination and the presence of E. coli as an indicator of fecal contamination in foods. In this study, 500 foods in 10 different groups, mainly dairy products, delicatessen products, salads, spices, cream...

For much of the twentieth century, coliform bacteria and especially Escherichia coli have been used as indicators of possible post-processing contamination and the presence of E. coli as an indicator of fecal contamination in foods. In this study, 500 foods in 10 different groups, mainly dairy products, delicatessen products, salads, spices, cream...

Aims: To reduce the analysis time needed for the enumeration of Escherichia coli, a rapid fluorogenic method (MUG) which takes only 48 h was compared with the standard most probable number (MPN) method which takes 6 days as described in the International Standards Organization (ISO). This study provides reliability data for the fluorogenic method...

For food and environmental analysis, coliform bacteria and especially E. coli should be determined and enumerated rapidly, correctly and economically. Even if the results are obtained either by traditional or improved techniques, the results require confirmation, meaning that these techniques are not reliable. Confirmation tests need additional tim...

An assay to screen Escherichia coli in foods using MUG supplemented lauryl sulfate tryptose (LST) broth instead of tryptone water (TW) medium was evaluated. The results presented in this paper suggest that this method is more sensitive for lower levels of E. coli, faster (16-18 It vs. 6-10 days) and less expensive (2.454 vs. 2.887 EURO/sample) than...

Bu çalışmada pastörize süt, yoğurt, peynir, tereyağı, dondurma, salata, şarküteri ürünleri, yaş pasta, baharatlar ve yaş meyve-sebze olmak üzere toplam 1067 gıda örneğinde TS 6063 ve TS 7725'e göre koliform grup bakteri, fekal koliform grup bakteri ve E. coli sayımı yapılmıştır. Analizler sonunda koliform bakteri, fekal koliformlar ve E. coli sıras...

255 minced beef, 101 soudjouk and 50 uncooked hamburger samples were analyzed for the presence of Escherichia coli O157:H7 serotype. m-EC and LST broths were used as selective enrichment media and SMAC agar was used as a selective isolation medium. A total of 3 E. coli O157 were isolated by conventional culture techniques; one from each of minced b...

Modified tryptic soy broth, lauryl sulfate tryptose broth, modified EC broth, sorbitol MacConkey agar and Fluorocult E. coli 0157 agar were tested for the recovery of 3 strains of Escherichia coli 0157:H7 against E. coli type 1 and Citrobacter freundii as common competitive microflora of raw meat products. Two-stepped trials showed that modified EC...

In this study effect of some separate and combined metabolic compounds produced by lactic acid were tested on food pathogenic and contaminant microorgnasms. For this study, five strains of each Lactobacillus bulgaricus and Streptococcus thermophilus were used. The inhibition effects of the metabolic products (lactic acid, hydrogen peroxide, acetald...