Wassergehalte tiefgefrorener Kammmuscheln

Kurzfassung Der Handel mit tiefgefrorenen Kammmuscheln (Pectinidae) hat in den letzten Jahren deutlich zugenommen und ist von der Jakobsmuschel (Pecten maximus) auf eine Reihe weiterer Spezies erweitert worden. Neben nicht zutreffender Handelsbezeichnung fällt diese Erzeugnisgruppe immer wieder durch einen erhöhten Wasserzusatz negativ auf. Es wurde die Zusammensetzung des Muskelfleisches von Produkten aus dem deutschen Handel bestimmt und das Wasser zu Protein- Verhältnis (W/P) berechnet. Eine erhebliche Zahl von Proben hatte hohe Wassergehalte und ein W/P Verhältnis > 5. Dies betraf insbesondere die Tiefseescallop (Placopecten magellanicus) und die Japanische Kammmuschel (Mizuhopecten yessoensis). In den meisten Fällen wurden Zusatzstoffe nachgewiesen, obwohl die gesetzlich vorgeschriebene Deklaration fehlte. Abstract The market share of quick-frozen scallops (Pectinidae) has increased significantly in recent years and has been extended besides the king scallop (Pecten maximus) to a variety of other species. Apart from an incorrect labeling this product group stands out for often excessively high water addition. The composition of the muscle meat and the water to protein ratio (W/P) was determined in samples from the German retail. The results showed that a considerable number of samples had very high moisture contents and W/P ratios > 5. These facts were mainly true for Placopecten magellanicus and Mizuhopecten yessoensis. There was no conformity with the prescribed declaration of food additives.

Blackening of canned prawn and its prevention

The paper gives an account of the types of blackening associated with canned prawn in brine and their control. It was found that blackening caused by iron sulphide could be controlled by maintaining proper titratable acidity of fill brine in cans. The paper also elaborates on the factors responsible for or governing this critical titratable acidity. In regard to copper sulphide blackening, control was found to be difficult by maintaining the acidity or by additives such as EDTA when the copper content in the material went above the critical level.

Effects of Zataria multiflora Boiss essential oil and nisin on the growth of Staphylococcus aureus in light salted silver carp fillet (Hypophthalmichthys molitrix)

There is an increasing demand in developing newer and safer methods in preserving food products.Among which herbal additives seem to attract evermore attention recently.the major advantage of herbal additives is due to their favorable aroma besides their antimicrobial effects and less expensive than chemical additives. Zataria multiflora Boiss is a native Iranian herb which is used vastly as a food preserver essential oils and also medical usage. Metabolites of harmless bacteria, such as Nisin are also known to be safe preservatives that have antimicrobial activity. However to establish the usefulness of natural antimicrobial preservatives, they must be evaluated alone and in combination with other preservation factors to determine whether there are synergistic effects in rigid media . In this study were evaluated the effects of different concentrations of Zataria multiflora (EO 0, 0.005, 0.015, 0.045, 0.135, 0.405 ,0.810 %) and Nisin(0, 0.15, 0.25, 0.75 μg/ml) and Storage time (up to 21 days) on growth of Staphylococcus aureus ATCC 6538 in a food model system(light salted fish of silver carp, Hypophthalmichthys molitrix). The results on growth of S. aureus were evaluated using SPSS 15.0 statistical software (SPSS 15.0 for windows, SPSS Inc.) and analyzed the logarithm of total count of the bacteria by Tukey Test. Results were considered statistically significant when P≤0.05. The growth of Staphylococcus aureus was affected significantly(P<0.05) by EO and Nisin and also combinations of EO and Nisin. Samples treated with 0.135, 0.405 and 0.810% of thyme essential oil showed a significant decrease on the growth of the bacteria compared with an treated samples(P<0.05). No significant difference was seen on the growth of S.aureus in samples treated with lower concentrations of Z.multiflora(below 0.045%) and untreated group(P>0.05). The most inhibitory effects were seen in samples treated with 0.405% and 0.810% of thyme essential oil until 9 and 12 days after storage,respectively. Also there was significant inhibtory effect(P<0.05) in different concentration of nisin on the organism compared with an treated samples. The synergism effects of the Eo and nisin on the growth rate of the bacteria was significant (P<0.05) compared with untreated samples and samples treated with the Eo or nisin, only. Synergismic effects was observed at concentration of 0.405 and 0.810% of Z. multiflora essential oil with 0.25 μg/ml Nisin, respectively until 15 days after storage. As expected it is preferred to apply the least possible amounts of additives in food preserving that not only are effective and safe but are economically justifiable.