The present study was carried out for detection and identification of Enterobacteriaceae in retailed and farm fish as Tilapia nilotica and Mugil cephalus and in Kafr El Shiekh Governorate. The obtained results were revealed that 47 Enterobacteriaceae strains were isolated from 50 Tilapia niloticus fish samples with a percentage of 94% (25 from retailed fish and 22 from farm fish). On the other side 46 isolates of Enterobacteriaceae strains were isolated from 50 Mugil cephalus with a percentage of 92% (22 from retailed fish and 24 from farm fish). The most dominants isolated strains were Citrobacter spp., Enteriobacter spp., Klebsiella spp., Proteus spp., and Serratia spp. This together with the highly pathogenic Enterobacteriaceae including Salmonella spp. and E. coli.

No abstract

Biogenic amines are nitrogenous compounds that posses biological activity. The source of its production is the microbial decarboxylation of amino acids. These compounds are found in various types of cheeses. The aim of this work was to determine the concentration of biogenic amines (histamine, tyramine and cadaverine) in some Egyptian cheese varieties. Sixty samples of Ras, Cheddar and Gouda cheeses (20 each) were collected randomly from hyper-markets and small-markets in Kafrelsheikh Governorate. The concentration of biogenic amines was assayed by using high performance liquid chromatography (HPLC). Tyramine was the most biogenic amine formed at high concentration in Ras cheese of both hyper and small-markets (total mean, 20.67± 3.84 mg/100g) followed by histamine (total mean, 16.27± 3.03mg/100g) and cadaverine (total mean, 12.23± 2.49 mg/100g). While Cheddar cheese followed by Gouda cheese showed concentrations of the examined biogenic amines lesser than that of Ras cheese. Matching these levels with the recommended standard by FDA ( 2001), high levels of biogenic amines in the examined cheese varieties exceeded the permissible value (10mg/100g) where 70% (each); 70, 80 and 50, 60% of hyper and small-markets Ras cheese samples were exceeded FDA permissible value for histamine, tyramine and cadaverine, respectively and cheddar cheese samples of hyper and small markets showed 50% (each); 50, 60 and 30, 40% were exceeded the permissible value, respectively, while 20, 40; 30, 50 and 30, 40% for hyper and small markets Gouda cheese samples, respectively, which poses a threat to public health. The public health importance of these biogenic amines was discussed and the recommendations were put.

Mercury and lead are highly toxic heavy metals which are found in the environment and affect on public health hazard. Mercury and lead are chemical elements which cannot be destroyed or broken down through heat treatment or environmental degradation resulting in a variety of human health hazard as lethal, sub lethal, acute and chronic toxicity. Therefore, this study was performed on one hundred samples of freshwater fish Clarias grapinus (C. gariepinus) and Oreochromis niloticus (Oreochromis. niloticus) and marine water fish Sardina pilchardus (S. pilchardus) and Pagrus pagrus (P. pagrus) that were collected at different times from various fish markets in kafr El-sheikh governorate, Egypt for determination of their heavy metal residues by Atomic Absorption spectrophotometer (AAS). The results showed that the mean values of mercury were 1.10±0.02, 0.89±0.01, 0.72±0.01 and 0.57±0.01 (mg/kg) in C.grapinus, O.niloticus, S.pilchardus and P.pagrus respectively. While, the mean values of lead were 0.64±0.01, 0.49±0.01, 0.33±0.01 and 0.27±0.01 (mg/kg) in such examined samples respectively. The public health significance and certain recommendations to control these serious pollutants were discussed.

Evaluation of some quality indices was carried out to determine the nutritional value of the most cultured freshwater fishes and to estimate the tolerance of these items to remain in good condition against damage. Quality indices were evaluated in 90 samples from three different fish species (Mugil cephalus, Oreochromis niloticus and Clarias gariepinus) 30 of each were collected at different times from different farms in Kafr Elshiekh Governorate, Egypt. Results of pH, total volatile nitrogen (TVN) "mg N /100g", trimethylamine (TMA)" mg /100g", thiobarbituric acid (TBA)" mg/kg" and peroxide value (PV)" meqO2/kg" were 6.

The effect of the antioxidant and antibacterial activity of thyme, ginger, lemon grass oils and nisin (200ppm) on sensory, chemical (PH, thiobarbituric acid "TBA" and total volatile nitrogen "TVN") and microbiological (aerobic plate count "APC", total coliform count and staphylococci count) quality of fresh minced beef during cold storage at 4º C were studied. It is noticed that, all essential oils and nisin used had considerable effectiveness in decreasing aerobic plate count (APC), coliform count and staphylococci count, as well as chemical indices (pH, TBA and TVN). Sensory analysis indicated significant advantages in using lemon grass, ginger oils, nisin and thyme oil respectively, in refrigerated minced beef. Results indicated that the bacterial counts, pH, TBA and TVN values decrease as the concentration of the oil increases since the concentration (1.5%) gives the best effectiveness. The antioxidant and antibacterial activities of the added essential oils followed the order lemon grass oil > ginger oil > thyme oil. However, nisin was the lowest effect on the bacterial counts except staphylococci count. These results suggest that lemon grass, ginger and thyme oils respectively, can play an important role as antioxidant and antibacterial agents in refrigerated minced beef and extend the shelf life of refrigerated minced beef more than the control samples by 6 days, and however nisin need more research to be more stable and effective against Gram-negative bacteria.

The aim of the present study was to determine the presence of Clostridium perfringens, including toxic genes in some meat products. A total of 80 samples of minced meat, beef burger, sausage and canned beef luncheon (20 of each) were collected from different supermarkets in Kafrelsheikh city. C.perfringes was isolated with incidence of 15, 15, 20 and 30%, respectively. Mean values of C.perfringes were 6.33x10 2 , 1.25x10 3 , 2.09x10 3 and 4.98x10 3 cfu/g, respectively. The tested meat product samples confirmed the presence of positive C.perfringes for toxic genes as cpa, cpb, etx, iap and cpe. The obtained results revealed that 16 positive C.perfringens isolates were classified into 5(31.25%) isolates were C.perfringens type A; 3(18.75%) C.perfringens type B; 2 (12.5%) C.perfringens type D; 1 (6.25%) C.perfringens type E, 5 (31.25%) were nontoxigenic C.perfringens and C.perfringens type C not detected in any of meat product samples. The result revealed that type A was the most predominant type. The percentage of toxigenic and non-toxigenic strains was 68.75% and 31.25%. The public health importance of the isolated organism was discussed.

In the current study, a total 90 samples were collected random way from three different fish species (Ttilapia niloticus, Mugil cephalus and Clarias) 30 of each type collected from Kafr El-Sheikh city, Egypt. These samples were subjected for bacteriological examination to evaluate the quality and freshness in farmed fish. The mean value of total bacterial count / g of Tilapia niloticus, Mugil cephalus and Clarias gariepinus were 6.73×10 4 ± 2.03 ×10 4 , 8.33×10 3 ±2.32× 10 3 and 4.1×10 3 ± 7.69×10 2 cfu/g, respectively. The mean values of coliforms count / g were 3.25×10 2 ± 8.04×10, 2.1×10 2 ± 6.74×10 and 1.06×10 2 ± 5.0×10 MPN/g, respectively. The mean values of staphylococcal count /g were 2.44×10 5 ±7.13×10 4 , 8.67×10 3 ±2.23×10 3 and 4.74×10 4 ± 7.48×10 3 cfu/g respectively.