Food control

Meeting consumer concerns and preferences for fresh and safely processed fisheries products free of chemical and synthetic preservatives is a challenge for the aqua-food industry. As such, natural preservatives from plant and animal origin including chitosan, essential oils (EOs), plant extracts and lactic acid bacteria have attracted considerable interest recently. These preservatives have antimicrobial and antioxidant properties that can retard spoilage, uphold product quality and safety as well as extend the storage shelf-life of fish and seafood. Chitosan and EOs have been successfully used in edible coatings, film wrapping and dipping solutions. The present review focuses on the effectiveness of chitosan, EOs and other natural preservatives intended for prolonging the shelf-life of fisheries products, and maintaining their freshness and quality. Moreover, the mechanisms of action of natural additives, harmful impacts of chemical preservatives and status of aquatic food preserva...

ABSTRACT Compared to most product supply chains, food supply chains are often more complex and more difficult to manage because the food product is perishable and has a short shelf life. A cold chain or temperature-controlled supply chain provides the essential facilities and methods required to maintain the quality and quantity of foods. Since foods can be time and temperature sensitive in nature, they need to be properly taken care of in terms of harvesting, preparation, packaging, transportation and handling – in other words, throughout the entire chain. Temperature is the most important factor in prolonging or maintaining the shelf life of perishables. Refrigeration is one of most widely used methods to date to slow the bacteria growth that leads to food deterioration. The proper control and management of temperature is crucial in delivering perishables to consumers and ensuring that those perishables are in good condition and safe to eat. This paper addresses the methods used to improve the ability to define an optimal target temperature for multi-commodity refrigerated storage. Simulation results support the fact that the presented methods provide more accurate results compared to the conventional method. In addition, an experiment with a Wireless Sensor Network (WSN) was conducted. As a result, the sensor-based methods for real time quality monitoring and assessment that consider product metabolism and Euclidean distance cost depending on temperature changes are found to be superior to the traditional visual assessment method.

Our objective was to investigate nitrate and nitrite contents of acidified and fermented fruits and vegetables. l -ascorbic acid and total phenols were also examined based on the hypothesis that the presence of these antioxidant compounds may influence N-nitrosation reactions upon human consumption. The fermented and acidified vegetable products included 131 samples from multiple lots of 46 different commercially available products. Nitrite was detected in low concentrations ( l -ascorbic acid content of 32 ± 10 mg/100 g, with a low nitrate level of 0.1 ± 0.09 mg/100 g. These results provide new information for evaluating nitrate and nitrite contents in pickled fruit and vegetable products with regard to potential human dietary health consequences.

The aim of this work was to compare refractometric index (RI) and Karl Fischer (KF) titration methods for moisture content measurement in honeys. In addition, the effectiveness of two different solvents (methanol (M) and methanol: formamide in the ratio 1:1 (M+F)) was evaluated. Results indicated that RI and KF methods yielded similar results for moisture determination in honeys; mainly, when the solvent M+F was used. This solvent mixture (M+F) also allowed a reduction in titration time which may be a potential advantage for measuring moisture content in honey.

A method is presented for the detection of Listeria monocytogenes in food, which produces definitive results on the third day after the sample collection. The method is equivalent to EN ISO 11290-1 or ISO 10560 in terms of the same detection limit of 100 cfu per 25 or 10 g and 100% relative accuracy. The version alternative to EN ISO 11290-1 begins with a primary enrichment in half Fraser broth (24 h), secondary enrichment in Fraser broth (24 h) and post-enrichment in brain heart infusion broth (5 h). The version alternative to ISO 10560 begins with enrichment in Listeria enrichment broth (48 h) and post-enrichment in tryptone soya broth (5 h). These steps are followed by bacterial cell lysis by boiling, PCR oriented to inlB gene using a mimic internal control, and agarose gel electrophoresis. At the evaluation of the method on model food samples artificially contaminated with decimal dilutions of a L. monocytogenes culture (cheese, smoked fish, ready-to-eat meat products; 21 samples altogether), a detection limit of 100 cfu per 25 or 10 g was determined. Dead L. monocytogenes cells did not cause false positivity, as determined using model food samples artificially contaminated with decimal dilutions of dead L. monocytogenes cells. At the evaluation of the method on naturally contaminated food samples (same as above, 140 samples altogether) identical results (8 positives) as with the reference method were obtained.

In the food industry pasteurisation is very commonly carried out using plate heat exchangers. Steady-state analysis of, and experimentation into, the effects of disturbances on the temperatures showed that temperature approach (water inlet temperature minus milk outlet temperature) changed very little. This showed that control based on a steady temperature approach could be effective. A control algorithm that calculates the

Natural losses from fruit and vegetable products stored in cold conditions are investigated. A mathematical model describing heat and mass transfer processes taking place during storage time is presented and the resulting governing equations are solved using Software Mathcad7. The relative humidity of the ventilating air and the temperature field of an apple bulk are found for different cold storage conditions; namely the initial air relative humidity and air flow rate. It was found that the relative humidity of the ventilating air approaches a limiting value as the apple bulk depth increases up to 4.2 m. In addition, when the relative humidity is larger than the equilibrium relative humidity value, an increase in the ventilating air rate reduces the losses of the product during the period of its storage while larger losses occur when the relative humidity values are lower than the equilibrium one.