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In this study the survival of Escherichia coli O157:H7 in the production process of acidophilus yogurt was examined and compared with traditional yogurt. Milk was inoculated with different doses of E. coli O157:H7 (10 2 , 10 4 and 10 6 CFU mL )1 ) and two kinds of yogurt were produced. Samples were taken for pH measurements and bacterial enumeration at 0, 3, 24, 48, and 72 h after inoculation. Escherichia coli O157:H7 was analysed by using a Most Probable Number technique and yogurt starter culture and Lactobacillus acidophilus were counted by using classical culture methods. Elimination times of E. coli O157:H7 were determined for 10 2 CFU mL )1 as 3 h, and for 10 4 and 10 6 CFU mL )1 as 48 h in acidophilus yogurt. Elimination times in traditional yogurt were 48 h for 10 2 and 10 4 CFU mL )1 and 72 h for 10 6 CFU mL )1 E. coli O157:H7. In conclusion, the elimination time of E. coli O157:H7 in acidophilus yogurt was shorter than in traditional yogurt during the processing and post-processing stages.

Sardines (Sardina pichardus) were vacuum packaged in polyethylene bags, and irradiated at 1, 2 and 3 kGy doses in a Co-60 d-irradiator. The unirradiated and irradiated samples were stored at 2 ± 1°C. Microbiological analyses were done for total aerobic mesophiles, micrococci and staphylococci, coagulase positive staphylococci, Enterobacteriaceae, coliform bacteria, Escherichia coli, and psychrophilic bacteria. Trimethylamine-nitrogen (TMA-N), thiobarbituric acid (TBA) and pH values were determined. Sensory attributes were also evaluated. In the unirradiated samples, TMA-N and pH values showed good correlations with sensory scores. There were no differences in TBA values between the irradiated samples. Based on microbiological criteria, the shelf-life increased two to threefold compared with the control samples. These experiments demonstrate that irradiation extends the storage life of pre-packaged sardines and that, for practical purposes, the different treatments make very little difference to the extension of shelf-life of acceptable product.

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Detumiııatioıı (d the coııtamiııation sources durillJ:;maııııfacturing stage of white cheese and studies 011 the preJ,elltion (d the coııtaminatioııs Summary: This study was undertakl'n to determine the sources and the level oj ui/1{(/mination o(111icroorf{anisms which c(lUsed to undesirable results in mWIU/ııcturinf{, ripeninf{ dnd consumption o(white cheese, and preı'ention eUi/1omic losses by investigated o!' prevelttiı'e process durinf{ manu!ııcturing plwse. Sa111ples were tak en {i-om pasteuri::.ec! milk, all equip111ents (cheese vats, press clıııh, cw/ı'as, culture hueket, curd cutler),' additives (mesophilic ([nd voghurt ıla rtas, CaCl], rennet), l)I'ine, curd, cheesq {iWl1 jirst doıı o(ripening periııd, ',vater, Iwnds o/personnel. ([ir,~valls and/foors sur/ııce o!,mmzu!,actııring unit that seleeted as 25 control point Microbiolof{ical wwlysis were made {(il' towl aerobic mesophilic coU/ıt, micrococci ve staphylococci, coaf{ulase positive staphvlococô, Enterohacteriaceae, colil(ınn hacteria, E co li, elJterococci, Pseudomonus spp .. i veast and molds, IT \ovasconcluded that, critical control points in nUlfw!ıu'turing o!' vı:hite cheese url'; /J(ısteurization process, using materials in nwnu(acturing process like press dıııhes and cwıv([s, air, and personne!, Sin ce dairvfactories have dilferent design" und nımıu/(ıcıurinf{ conditions, critica i conf/ıol points should be determined {(ii' eaclı {aetol'V.