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Sliced ready-to-eat traditional meat products presented in individual packaging with more convenience to the consumer is the way that food industry tries to adapt to the new consumer tendencies.
The current work assessed the survival of Listeria monocytogenes in a contaminated sliced vacuum packed chouriço with different sugar concentrations, two salt levels, and presence/absence of Lactobacillus sakei as starter culture along the storage period at two temperatures (8 °C and 22 °C). Neither the inoculation with L. sakei, nor the addition of carbohydrates influenced the survival of the pathogen. Higher amount of salt resulted in a significant reduction of L. monocytogenes, and storage at the higher temperature displayed a safer product. After 7 days, L. monocytogenes was not detected in any samples. The study of the association of the factors contributing for L. monocytogenes survival by logistic regression showed that increasing the level of salt addition from 1.5% to 3% reduces the odds of survival of L. monocytogenes to about one fifth (0.174). Worthy of attention is the significant reduction in the odds (OR=0.028) of finding viable L. monocytogenes when the samples are stored at room temperature (22 °C), when compared to low temperature (8 °C).
The general and indiscriminate use of refrigeration for meat products might increase the risk of presence of L. monocytogenes. The competitive advantage that L. monocytogenes has at low temperatures, as the potential inhibition of LAB activity, is probably the reason of the observed behaviour. The amount of salt was an important hurdle to control L. monocytogenes growth, so, manufacturing meat products with lower salt contents to meet the demands of healthy products might represent a risk for safety, since high levels of salt together with low aw are the keys for their conservation.
In Spain the consumption of bakery products is increasing, while that of bread is decreasing. Baked goods have a high fat and sugar content, and their intake accounts for a high percentage of the food consumed by the population for breakfast, mid-morning and mid-afternoon meals. Twenty products, with and without cream and chocolate, were analysed. The nutrients examined were proteins, fats and fatty acids, carbohydrates, sugars, starch, and fibre. The values for carbohydrates ranged between 36.8% and 62.3%, and for sugars between 9.0% and 33.8%. The fat content ranged from 6.0% to 36.8%, while 76% of the saturated fatty acids (SFA) determined were atherogenic acids. In accordance with daily energy intake recommendations for SFA and sugars, the intake of one serving of the product provides 25% or more of the recommended energy from SFA for nine of the twenty baked goods tested, and more than 15% of the energy recommended from sugars for fourteen of these products.
The effectiveness of five commercial disinfectants used in the food industry was evaluated against different strains isolated from foodborne outbreaks (E. coli O157:H7, Salmonella spp. and L. monocytogenes) and a collection strain (S. aureus) in an aqueous suspension medium. The disinfectants evaluated included quaternary ammonium compounds, aldehydes, hydrogen peroxide and peracetic acid, clorhexidine and a tertiary alkylamine. In the absence of organic matter, all the disinfectants tested were effective with an exposure time of 10 min at the lowest concentration recommended by the manufacturer. However, in the presence of organic matter their effectiveness decreased. The most effective disinfectant against pathogenic bacteria tested was a quaternary ammonium compound based disinfectant combined with non-ionic surfactants, polyphosphates and alkaline salts. The least effective ones were disinfectants containing tertiary alkylamine, peracetic acid and hydrogen peroxide.
The anthocyanin pattern of 18 grape cultivars grown under the same conditions during several years, and also the anthocyanin pattern of wines made from them, using the same winemaking technology, has been studied by HPLC. Chromatographic data indicate that every grape cultivar present a characteristic anthocyanin pattern, that is reflected in wines made from them. Two-way ANOVA and variance component analysis point out that the anthocyanin pattern of grapes and wines is mostly affected by the genetic characteristics of grape cultivars. Moreover, the use of multivariate statistical analysis (principal component analysis and discriminant analysis) allows the classification of grapes and wines into several groups on the basis of their anthocyanin pattern, and shows that the anthocyanin pattern of young single-cultivar wines is related to the anthocyanin pattern of grapes used for winemaking. Results may be relevant for using the anthocyanin pattern of young single-cultivar wines as an analytical tool to determine the grape cultivar used to make them.
The aim of this study was to investigate the effect of some food additives used in foods on cold tolerance of Clostridium perfringens at pH close to neutral.Maximal concentrations recommended for foods of sodium benzoate, potassium sorbate, sodium nitrite, monosodium glutamate, or mixtures of those were added to cultures and their effects on C. perfringens tolerance to 10 °C were evaluated. The effect of a previous shock at 28 °C was also determined. Growth of C. perfringens was not inhibited by the substances examined. Sodium nitrite, applied at maximal permitted concentrations, increased C. perfringens survival at 10 °C. Mixtures of GRAS compounds had either no clear effect, or increased tolerance to 10 °C. A pre-shock (28 °C) of the cultures treated with sodium benzoate, sodium nitrite or monosodium glutamate increased survival and stimulated growth of the cultures treated at 10 °C.We conclude that the addition of these compounds including sodium benzoate, potassium sorbate, sodium nitrite and monosodium glutamate to cultures of C. perfringens can influence their cold tolerance. In some cases, the substances that would normally eliminate microorganisms at lower pH, can increase tolerance of this bacterium, permitting survival at low temperatures.
Abstract
The effect of processing parameters on microencapsulation of oregano essential with maltodextrin:gum arabic using a disk atomiser spray-dryer was evaluated. By means of response surface methodology, the feed flow rate and inlet air temperature were optimised. Powder yield, moisture content, essential oil retention, and antioxidant activity of microparticles were evaluated. The best conditions to produce microencapsulated oregano essential oil were 0.6 L h−1 for feed flow rate and 200 °C for inlet air temperature. With this combination a microencapsulated powder with 89.8% powder yield, 2.1% moisture content, 92.1% essential oil retention, 76 s solubilisation time, 12.9 g of water/100 g of dry matter, 0.3371 g mL−1 bulk density, 0.5826 g mL−1 tapped density, and 8.2 μm of average particle size was produced. The microencapsulation of oregano essential oil preserves the antioxidant and antimicrobial activities of its bioactive compounds.
The aim of this research was to assess the total antioxidant activity (TAA) of lipophilic (Lextr) and hydrophilic (Hextr) tomato extracts using in vitro chemical tests and cell-based assays, focusing on possible synergistic actions between tomato antioxidants. Both Hextr and Lextr were HPLC analysed for their carotenoids, phenolic compounds, and ascorbic acid contents. For the evaluation of TAA, extracts were assayed alone or in combination using in vitro chemical tests (TEAC, FRAP) and cell-based (CAA) assays using human hepatoma (HepG2) and human histiocytic lymphoma (U937) cells. The only carotenoid detected in Lextr was lycopene, while a mixture of phenolic compounds (chlorogenic acid, caffeic acid, and rutin) was identified in Hextr. Ascorbic acid was not found either in Hextr or in Lextr. Upon extract combination (1:1, v/v), the FRAP assay revealed additive action between Lextr and Hextr, whilst a slight synergistic action was observed in TAA as measured by the TEAC assay. Synergistic action was better revealed when TAA was analysed using either U937 or HepG2 cells. This could be explained by the presence of a multiphase media (cell membrane and extra- and intracellular media) that might facilitate the distribution and interaction of antioxidants with different polarities and different mechanisms of action.
The best alternative for reducing citrus production costs is mechanization. Machine vision is a reliable technology for the automatic inspection of fresh fruits and vegetables that can be adapted to harvesting machines. In these, fruits can be inspected before sending them to the packinghouse and machine vision provides important information for subsequent processing and avoids spending further resources in non-marketable fruit. The present work describes a computer vision system installed on a harvesting machine developed jointly by IVIA and a Spanish enterprise. In this machine, hand pickers directly drop the fruit as they collect it, which results in an important increase of productivity. The machine vision system is placed over rollers in order to inspect the produce, and separate those that can be directly sent to the fresh market from those that do not meet minimal quality requirements but can be used by the processing industry, based on color, size and the presence of surface damages. The system was tested under field conditions.
The effect of sequential treatments of pressure (50–150 MPa, 10 ºC, 5 min) and temperature (57 ºC, 15 min) on the survival and bacteriocin production of Pediococcus acidilactici HA-6111-2 cells in the exponential growth phase was assessed. The growth curves were fitted with the modified Gompertz model, and the estimated maximum specific growth rate was considered to be pressure dependent. A delay in the maximum value of bacteriocin production was registered for more severe pressure conditions, but it was found more notorious for pressure followed by temperature treatments. At lower pressure intensity treatment, regardless of the application order, there was an enhancement of bacteriocin production per cell when compared to the control while maintaining the maximum production value. Bacteriocin production after the treatments can be described by an exponential model.
Abstract
Tomato is rich in different bioactive compounds, especially the carotenoid lycopene, which intake is associated with various health benefits. Post-harvest use of ultraviolet light (UV) and light-emitting diode (LED) has been shown to increase the concentration of tomato bioactive compounds. The aim of this study was to evaluate the effect of ultraviolet (A and C) and red-blue LED light on the concentration of carotenoids during a 7-days storage trial of mature green tomatoes. Exposure to combined UV and LED light nearly doubled the total carotenoid concentration and had no negative impact on sensory attributes.
