Citrinin production and stability in cheese

Citrinin is a nephrotoxic fungal metabolite that has been demonstrated to be mutagenic in hepatocytes. It can be produced by several fungal species that belong mainly to the genus Penicillium and has been isolated from many feeds and human foods. Cheese is a very sensitive product because it can be naturally contaminated by citrinin-producing molds. The purpose of this study was to determine whether citrinin can be produced in cheeses and whether it is stable in these products. Both toxigenic strains of Penicillium citrinum and Penicillium expansum used were able to produce citrinin in cheese at 20 degrees C, but not at 4 degrees C. Up to 600 mg of citrinin per kg of cheese was obtained after 10 days of incubation. Interestingly, fresh goat cheese appeared to be a more favorable substrate for toxigenesis than did yeast extract-sucrose medium. Although contamination was mainly superficial, 33% of the toxin remained in cheese after trimming. Moreover, citrinin appeared to be very stable in some of the tested cheeses (goat cheese, Saint Marcellin, Soignon). For all cheeses tested, more than 50% of the initial content of citrinin was still present after 8 days of storage. Taken together, these results suggest that the contamination of cheeses by wild strains of Penicillium must be avoided.     

DETERMINATION OF REPEATABILITY AND REPRODUCIBILITY OF EBC ACCEPTED METHODS IV—COLOURED MALTS

Methods for the determination of caramel and roasted malt moisture, extract and colour published in Analytica EBC have been collaboratively tested by the European Brewery Convention Analysis Committee, according to the ISO standard 5725. Repeatability (r₉₅) and reproducibility (R₉₅) values are presented.     

An Investigation of the Failure Mechanisms of a Polymer Matrix Composite Crew Oar

Journal of Failure Analysis and Prevention - Rowing, or crew, is a constantly evolving sport with an impressive history of equipment advancements, including the use of advanced polymer matrix...     

Blood and tissue distribution of gamma glutamyl transferase in the cow.

To test the hepatic specificity of gamma-glutamyl transferase in the cow, the tissue distribution of this enzyme was studied in 10 healthy adult cows. It was located mainly in kidney, pancreas, and liver. The relative hepatic specificity of this enzyme indicated that measurement of its activity in serum could be a valuable test of hepatic damage in the cow. The blood activity measured within 54 plasmas and 54 serums of apparently healthy animals was almost the same, 17.7 +/- 5.7 U/liter for plasma and 18.6 +/- 6.2 U/liter for serum.     

Two‐dimensional gel electrophoresis of apolipoprotein C‐III and other serum glycoproteins for the combined screening of human congenital disorders of O‐ and N‐glycosylation

Congenital disorders of glycosylation (CDG) are inherited diseases that can affect not only the N‐glycan (e.g. CDG type I and II) but also the O‐glycan biosynthesis pathway. In the absence of specific clinical symptoms, there is a need for a reliable biological screening of these two groups of CDG. Using a few microlitres of human serum, 2‐DE and immunoblotting were applied to the separation and simultaneous detection of the isoforms of the O‐glycosylated protein apolipoprotein C‐III (apoC‐III) and of four N‐glycosylated proteins, namely alpha‐antitrypsin, alpha‐1 acid glycoprotein, haptoglobin and transferrin. For the study of O‐glycosylation, this technique allowed the reliable separation of the three fractions of apoC‐III and the determination of normal percentage values in an adult population. Concerning N‐glycosylation, the study of serum samples from patients with CDG type Ia revealed marked abnormalities systematically affecting the four 2‐DE separated N‐linked glycoproteins. 2‐DE coupled to immunoblotting using a mixture of specific antibodies could be easily and reliably employed for the combined screening of both N‐ and O‐glycosylation disorders in humans.     

Apoptotic process in the monkey small intestinal epithelium: 2. Possible role of oxidative stress

Recent findings suggest that intracellular oxidants are involved in the induction of apoptosis and this type of cell death can be inhibited by various antioxidants. In our accompanying paper, we have shown apoptosis in the villus tip cells of the monkey small intestinal epithelium. The aim of the present study was to evaluate the possible relationship between oxidative stress, antioxidant levels and the apoptotic process in the monkey small intestinal epithelium. Monkey small intestinal epithelial cells were isolated into different fractions consisting of villus, middle and crypt cells. Mitochondrial function was assessed by the reduction of the tetrazolium dye, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), with and without succinate. The extent of lipid peroxidation was assessed by measuring the formation of conjugated diene, depletion of polyunsaturated fatty acids and alpha-tocopherol. Level of antioxidant enzymes like, superoxide dismutase (SOD), catalase, glutathione S-transferase (GST), glutathione peroxidase (GPx) and glutathione reductase were also quantitated in various cell fractions. MTT reduction was significantly decreased in villus cells as compared to the cells from other fractions and this was evident even in presence of the respiratory substrate, succinate. Increased formation of conjugated diene and depletion of polyunsaturated fatty acids were seen in villus and crypt cells as compared to middle fraction cells. The alpha-tocopherol level was decreased in both villus and crypt cells as compared to cells from middle region. Significant decrease of SOD activity was seen in the villus tip cells and a slight decrease was seen in the crypt fractions. Glutathione dependent enzymes like GST, GPx and GSH reductase showed higher activity in the villus fractions. A similar observation was also seen in the catalase activity. This study has shown that although oxidative stress is seen in both villus and crypt cells, decreased mitochondrial function was seen in villus tip cells which may be responsible for apoptotic process in the intestinal epithelium.     

The Correlation Between In Vitro Antioxidant Activity and Immunomodulatory Activity of Enzymatic Hydrolysates from Selenium‐Enriched Rice Protein

The antioxidant and immunomodulatory activities of selenium‐enriched rice protein hydrolysates (Se‐PH) were evaluated by a cellular antioxidant activity test and macrophage proliferation and phagocytosis assays, respectively. The results showed that trypsin hydrolysate provided the highest proliferation rate of 60.91% at a concentration of 100 μg/mL. Moreover, a remarkable rise in the phagocytosis rates for trypsin hydrolysate (64.1%) and pepsin–trypsin hydrolysate (54.5%) was observed when the sample concentrations were increased to 50 μg/mL. A positive correlation was found between the phagocytic ability of macrophages and both the selenium concentration and the degree of hydrolysis of Se‐PH, and the correlation coefficients R obtained were 0.792 and 0.930 (P < 0.05), respectively. The capacity of Se‐PH to inhibit the oxidation of dichlorodihydrofluorescein had a significant negative correlation with the phagocytic ability of macrophages (R = –0.840, P < 0.05). In conclusion, a positive correlation was found between the antioxidant activity and the immunomodulatory activity of Se‐PH, which could be used as potential functional food additives for improving human health.     

Prevalence and characterization of Escherichia coli O157:H7 isolates from meat and meat products sold in Amathole District,Eastern Cape Province of South Africa

Meat and meat products have been implicated in outbreaks of Escherichia coli O157:H7 in most parts of the world. In the Amathole District Municipality of the Eastern Cape Province of South Africa, a large number of households consume meat and meat products daily, although the microbiological quality of these types of food is questionable. The present study investigated the prevalence of E. coli O157:H7 isolated from selected meat and meat products (45 samples each of biltong, cold meat, mincemeat, and polony) sold in this area. Strains of E. coli O157:H7 were isolated by enrichment culture and confirmed by polymerase chain reaction (PCR). Also investigated were the antibiogram profiles of the E. coli O157:H7 isolates. Five (2.8%) out of 180 meat and meat products examined were positive for E. coli O157:H7 that carried the fliC_H7, rfbE_O157, and eaeA genes. Two of the E. coli O157:H7 isolates were resistant against all the eight antibiotics tested. To prevent E. coli O157:H7 infections, meat and meat products such as biltong, cold meat, mincemeat and polony should be properly handled, and packed in sterile polyvinyl wrappers.