CONSIDERATIONS FOR THE APPLICATION OF TIME-TEMPERATURE INTEGRATORS IN FOOD DISTRIBUTION

Agribusiness,

CURRENT PRACTICES AND REGULATIONS REGARDING OPEN DATING OF FOOD PRODUCTS

A federally regulated open dating system on food products, instead of the current somewhat random and non-uniform state mandated system, would most likely benefit today's consumers, retailers, and government agencies. Consumers have indicated a strong desire for open dates; it would enhance their ability to make educated choices about the freshness of the foods they consume. A mandatory/uniform system would also assist retail grocers with stock rotation, so that customers can be provided with the best products available. Finally, federal open dating regulations across state borders would lessen burdens on interstate commerce. The potential benefits of this dating system outweigh the opposing points-of-view. The purpose of this research is to illustrate and discuss the current practices and regulations regarding open dating of food. Included in this study are the current federal and state regulations. Fifty-nine percent of the states (including the District of Columbia) currently mandate some sort of open dating on food products. The regulations vary on a state-by-state basis from mandatory dating of all perishable foods to open dating on a completely voluntary basis. While most consumers want to see open dates, educating them about what the dates mean is necessary but currently not being done. A major disadvantage of an open dating system is that it may be deceiving if the food is not properly handled, i.e. the date is based on some average storage condition. There are many modes of food deterioration, and most are dependent on a time- temperature interdependence. This research acknowledges that open dating of food is useful as a guide to the end of shelf-life, but its regulated implementation used in conjunction with time- temperature integrators is a more dependable indicator of freshness and safety for the consumer.Food Consumption/Nutrition/Food Safety,

PERISHABLE REFRIGERATED PRODUCTS AND HOME PRACTICES SURVEY

The "Perishable Refrigerated Products and Home Practices Survey" was a two-part survey developed to better understand consumers' perceptions and their current level of understanding regarding the proper handling and storage of perishable refrigerated foods. Past studies (e.g. Anonymous, 1997a; Anonymous, 1999a) have demonstrated a lack of consumer knowledge in such areas involving food safety practices. In recent years, there have been a number of large food recalls (i.e. Anonymous, 1997b; Anonymous, 1999b; CDC, 1999) due to the presence or possible presence of foodborne pathogens. Part of this study analyzed consumers' knowledge and attitudes towards the recalled products. A large number of foodborne outbreaks also occur in the household. After examining participant responses concerning food handling practices, (i.e. improper temperature control and lack of food rotation habits), the practices of many of the participants were not suitable to prevent possible foodborne contamination. Open dates and time-temperature integrators (TTI's), especially when used together, can assist consumers in purchasing fresh foods (Taoukis and Labuza, 1989a, b). However, numerous past studies have indicated consumer confusion regarding the meaning of open dates; and the results of this study confirm that the confusion continues. This may be due in part to the fact that there is no federally mandated, uniform open dating legislation in this country. TTI's are a fairly new device on the U.S. marketplace. While participants in this study were optimistic about the potential benefits of TTI's, 76% of consumers were unfamiliar with the device.Food Consumption/Nutrition/Food Safety,

Kinetics of ascorbic acid degradation in fruit-based infant foods during storage

The kinetics of ascorbic acid (AA) degradation in a fruit-based beikost product added with AA were determined after storage at 4, 25, 37 and 50 °C during 4, 8, 12, 16 and 32 weeks in plastic polypropylene/ethylenevinyl alcohol vacuum packaging. It was confirmed that AA degradation followed an Arrhenius first-order kinetics, with an activation energy of 20.11 ± 0.33 kcal mol−1. No AA losses at 4 °C were recorded during the entire storage period. In contrast, a time - and temperature - dependent decrease (p the degradation rate decreasing from 50 °C to 25 °C, as expected. AA percentage retention at the end of storage ranged between 6.4% (50 °C/16 weeks) and 100.9% (4 °C/32 weeks)

Relationships between hydrodynamics and rheology of flocculating yeast suspensions in a high-cell-density airlift bioreactor

In this article a hydrodynamic and rheological analysis of a continuous airlift bioreactor with high-celldensity system is presented. A highly flocculating recombinant strain of Sacharomyces cerevisiae containing genes for lactose transport (lactose permease) and hydrolysis (β-galactosidase) was exploited to ferment lactose from cheese whey to ethanol. The magnetic particle-tracer method was used to assess the effect of operational conditions (air-flow rate, biomass concentration) on hydrodynamic behavior of an airlift bioreactor during the fermentation process. Measurements of liquid circulation velocity showed the existence of a critical value of biomass concentration at which a dramatic deceleration of net liquid flow appeared with increasing biomass quantity. Rheological analysis revealed exponential increase of viscosity of the yeast floc suspension at the same biomass concentration of about 73 g/dm³ corresponding to 42.8% v/v of solid fraction. These facts have a particular importance for the successful processing of a high-celldensity airlift bioreactor as only a circulated flow regime will be favorable to keep the solid particles in suspension state and evenly distributed throughout the bioreactor.União Europeia (UE). Marie Curie Fellowship of the European Community Programme - grant number HPMF-CT-2002-01643

Effect of different storage conditions on analytical and sensory quality of thermally processed milk based germinated Foxtail millet porridge

Foxtail millet porridge was prepared using germinated grains and milk and was evaluated for its storage stability after thermal processing at Ultra High Temperatures (UHT) of 142 oC for 5 s and Retort processing temperatures of 121.5 oC for 15 min. Various physical, chemical and microbial changes of the porridge were studied for a storage period of 180 days at 25 ± 1 oC. Using consumer perception and survival analysis, the predicted shelf life of the UHT treated and retort processed foxtail millet porridge samples stored at 25 ± 1 oC was found to be 186 ± 9 days and 245 ± 15 days, respectively. Also, data from consumer liking, profiling, physical, chemical and microbial parameters showed significant changes (p < 0.05) in the thermally treated packaged porridge samples over time. As the consumer overall acceptability decreased, the detection of positive attributes (Thick and uniformly coloured texture and appearance; grainy mouth texture; caramel taste and aroma) in the porridge decreased, while the detection of negative attributes (Uneven, decoloured, and curdled texture and appearance; sticky mouth texture; cooked, sour and off smell; cooked, sour and off taste) increased. The present study could establish a significant difference (p < 0.05) in the storage induced properties of UHT and retort processed porridge samples. The analytical evaluation of foxtail millet porridge found that UHT treated porridge was better in quality, but consumers preferred retort processed porridge

Computational shelf-life dating : complex systems approaches to food quality and safety

Shelf-life is defined as the time that a product is acceptable and meets the consumers expectations regarding food quality. It is the result of the conjunction of all services in production, distribution, and consumption. Shelf-life dating is one of the most difficult tasks in food engineering. Market pressure has lead to the implementation of shelf-life by sensory analyses, which may not reflect the full quality spectra. Moreover, traditional methods for shelf-life dating and small-scale distribution chain tests cannot reproduce in a laboratory the real conditions of storage, distribution, and consumption on food quality. Today, food engineers are facing the challenges to monitor, diagnose, and control the quality and safety of food products. The advent of nanotechnology, multivariate sensors, information systems, and complex systems will revolutionize the way we manage, distribute, and consume foods. The informed consumer demands foods, under the legal standards, at low cost, high standards of nutritional, sensory, and health benefits. To accommodate the new paradigms, we herein present a critical review of shelf-life dating approaches with special emphasis in computational systems and future trends on complex systems methodologies applied to the prediction of food quality and safety.Fundo Europeu de Desenvolvimento Regional (FEDER) - Programa POS-ConhecimentoFundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/26133/2005, SFRH/ BPD/20735/200

Analysis of storage stability of intermediate moisture foods

Analysis of storage stability of intermediate moisture foods for space flight feeding with tables of foods and types of manufactur

Mechanisms of deterioration of intermediate moisture food systems

A study of shelf stability in intermediate moisture foods was made. Major efforts were made to control lipid oxidation and nonenzymatic browning. In order to determine means of preventing these reactions, model systems were developed having the same water activity content relationship of intermediate moisture foods. Models were based on a cellulose-lipid and protein-lipid system with glycerol added as the humectant. Experiments with both systems indicate that lipid oxidation is promoted significantly in the intermediate moisture range. The effect appeared to be related to increased mobility of either reactants or catalysts, since when the amount of water in the system reached a level where capillary condensation occurred and thus free water was present, the rates of oxidation increased. With added glycerol, which is water soluble and thus increases the amount of mobile phase, the increase in oxidation rate occurs at a lower relative humidity. The rates of oxidation were maximized at 61% RH and decreased again at 75% RH probably due to dilution. No significant non-enzymatic browning occurred in the protein-lipid systems. Prevention of oxidation by the use of metal chelating agents was enhanced in the cellulose system, whereas, with protein present, the lipid soluble chain terminating antioxidants (such as BHA) worked equally as well. Preliminary studies of foods adjusted to the intermediate moisture range bear out the results of oxidation in model systems. It can be concluded that for most fat containing intermediate moisture foods, rancidity will be the reaction most limiting stability

Storage Stability and Improvement of Intermediate Moisture Foods

Shelf life tests are used to estimate the rate of nonenzymatic browning; however, controlling the reducing sugar levels below 23:1 molar ratio to amines, slows the rate. In addition, liquid glycols surpress browning. The protozoan Tetrahymena pyriformis W can be used to estimate nutrition losses during browning. At high temperatures (80 to 120 C) used in processing intermediate moisture foods (IMF), vitamin C destruction shifts to a zero order mechanism. BHA and BHT are the most effective antioxidants against rancidity. In shelf life testing however, 45 C should be the maximum temperature used. Water binding agents are studied. The five isotherms of thirteen humectants were determined. The results show that neither the method of addition nor sequence of addition affects the a sub u lowering ability of these humectants. Results were used to formulate shelf stable IMF processed cheese foods with at least four months shelf life