Packaging Bags Research Articles

Survival of Listeria monocytogenes in Postpasteurized Precooked Beef Roasts

The potential for Listeria monocytogenes to survive various times and temperatures of postpasteurization in precooked beef roasts was investigated. Precooked eye of round roasts were inoculated with 109 cells of L. monocytogenes per package prior to packaging in cook-in bags and postpasteurization. Four groups of roasts (n = 54) each containing 27 uninoculated and 27 inoculated roasts were allotted to four pasteurization treatments consisting of two different exposure temperatures (91°C, 96°C) and two different dwell times (3 min, 5 min). Equal numbers of inoculated and uninoculated roasts from each treatment were then stored at 4 and 10°C. Triplicate samples of inoculated and uninoculated roasts were sampled on day 1, 4, 8, and 12 for product stored at 10°C and 1, 8, 14, 28, and 56 d for product stored at 4°C. Survivors were encountered for every treatment employed. The lethality of the treatment was directly related to an increase in dwell time and postpasteurization temperature. Treatment 4 (96°C, 5 min) was found to decrease the L. monocytogenes population the greatest (p < 0.05) and also maintained a lower (p < 0.05) count from its initial inoculum level during storage at both 4 and 10°C.

Curing, wash water chlorination and packaging to improve the post-harvest quality of Xanthosoma cormels

Curing Xanthosoma caracu Koch et Bouche cormels at 30 or 35°C and 95–100% relative humidity (RH) for 7 days significantly reduced weight loss and decay during storage under simulated ambient conditions of 25°C and 75% RH, compared to curing at 40°C or not curing. Wash water chlorination (1% NaOCI) significantly reduced decay compared to untreated water washing or dry brushing, but did not reduce decay compared to no cleaning. Packaging corms in perforated plastic bags or burlap bags significantly reduced water loss and maintained better appearance, but effects on decay were inconsistent. Storage in non-perforated plastic bags greatly increased decay and sprouting of the cormels. The combined effects of curing, wash water chlorination and packaging in perforated plastic bags markedly improved the appearance and marketability of the cormels.

Use of electron spin resonance for the determination of staling of roast coffee in polyethylene bag packs

Arabica roasted beans packed in polyethylene bags were investigated at intervals by chemical analysis (acidity index) and by electron spin resonance (ESR) over a period of 30 days. The ESR measurements were repeated on the same samples after being exposed to air over a period of 30 days. Simultaneously, the acidity index of beans in an open bag was determined at regular intervals. ESR studies were also performed on ground beans, which were maintained in contact with air in two different containers. For all samples, the ESR intensity decreased as a function of time, whereas the acidity index increased simultaneously. The rate of change depended upon the treatment of the sample as well as on the storage time in the bag. On the basis of the ESR results an ageing velocity is defined, which allows for the quantification of the staling of roast coffee.

Cytokinins Affect Respiration, Ethylene Production, and Chlorophyll Retention of Packaged Broccoli Florets

Broccoli (Brassica oleracea L. var. italica `Citation') florets were treated postharvest with either benzyladenine or trans-zeatin at either 10 or 50 ppm before packaging in perforated polyethylene bags and storage at 16C. The most pronounced effects were observed with benzyladenine at 50 ppm. Compared to controls, respiration rate was reduced 50% and ethylene production increased 40% throughout the first 4 days of storage. Total chlorophyll content had dropped 60% in controls, but was unchanged in cytokinin-treated florets, which had a 90% longer shelf life than controls. These effects depended on the amount of cytokinin applied and were of greater magnitude with benzyladenine than with zeatin.

Correlation of Tests for Material Dustiness with Worker Exposure from the Bagging of Powders

Abstract A significant correlation was found between worker dust exposure from a bag packing operation and the results of two dustiness testers. The dustiness testers were the Heubach Dust Measurement Appliance and the Midwest Research Institute (MRI) Dustiness Tester. Both the Heubach and MRI dustiness tester predicted dust exposures to within an order of magnitude for the operation studied. The width of the prediction interval reflects typical variability in worker dust exposure measurements. Although the correlation between dustiness test results and dust exposures may be different for other operations, these results suggest that dustiness tests can be used to compare the relative potential of different materials to cause dust exposures. Heitbrink, W.A.; Todd, W.F.; Fischbach, T.J.: Correlation of Tests for Material Dustiness with Worker Exposure from the Bagging of Powders. Appl. Ind. Hyg. 4:12–16; 1989.

Studies on the shelf life and quality of Robusta bananas as affected by post-harvest treatments

SummaryThe effects of skin coating with ‘Waxol’ (6%) and ‘Tal Prolong’ (1.0% and 2.0%) combined with packing in polyethylene bags and the use of the ethylene absorbent ‘Purafil’, on the physiochemical changes and ripening of cv Robusta banana were compared at ambient storage conditions (21–28°C; 70–90° RH). There were no differences in ripening between untreated and Waxol (6%)-treated fruits but 1% and 2% Tal Prolong delayed ripening by 4 to 5 days. Waxol-and Prolong-treated fruits kept in ventilated polyethylene packs showed delayed ripening by 6 days, and untreated fruits kept in sealed Purafil packs also showed a 7-day delay in ripening. This delayed ripening was correlated with reduced rates of softening, and the development of yellow surface colour and with increases in moisture, the pulp:peel ratio, acidity, tannin, total sugar, starch and alcohol-insoluble residue contents in the pulp of the fruit. Weight loss during storage was considerably less in fruits kept in polyethylene bags than in unpacked...

Growth of Salmonella typhimurium and Mesophilic Organisms on Beef Steaks as Influenced by Type of Packaging

Two trials, each utilizing 72 samples of fresh beef loin steak, were done to determine the effects of various packing systems upon growth of Salmonella typhimurium. Samples were inoculated with 105 cells/cm2 of the organism and randomly assigned to four packaging treatments: (1) overwrapping in oxygen-permeable film; (2) vacuum packaging; (3) packaging in barrier bags flushed with a 60% CO2: 40% O2 gas atmosphere then evacuated and sealed; and (4) packaging in barrier bags filled with a 60% CO2: 40% O2 gas atmosphere. Twelve steak samples were inoculated with S. typhimurium and 6 were uninoculated and served as a control in each treatment group. Samples were displayed in retail meat cases at 10 C for 3, 6 or 9 days, when they were evaluated for shrinkage and numbers of mesophilic organisms and S. typhimurium. Percent shrinkage was not affected (P>0.05) by packaging treatment. Counts of mesophilic organisms were similar (P>0.05) for vacuum- and gas-treated steaks, which were significantly lower (P<0.05) than counts from film overwrapped samples. Numbers of S. typhimurium increased significantly (P<0.05) during storage on samples wrapped with oxygen permeable film but remained low and fairly constant for vacuum- or gas-treated steaks. After 9 days of display, the film overwrapped steaks had greater (P<0.05) numbers of S. typhimurium than those of other treatments, whereas steaks held within the 60% CO2: 40% O2 gas atmosphere had lowest numbers overall.

Facial Blemishes and Their Treatment

An approach to head and neck skin lesions is presented as an alternative to excisional surgery. Dermaplaning, curettage, electrodesiccation, cryosurgery, and chemosurgery are presented as alternative approaches to the eradication of selective skin lesions.

Delaying Deterioration of Romaine Lettuce by Vacuum Cooling and Modified Atmosphere Produced in Polyethylene Packages1

Abstract Yellowing and decay of leaves were reduced when romaine lettuce (Lactuca sativa L. cv. Hazera Yellow) was prepackaged in closed polyethylene (PE) bags in which O2 concentration was reduced by flushing with N2. Similar, but less effective results were obtained when the lettuce was prepackaged in closed PE bags (not flushed with N2 gas), or when open bags were placed in PE-lined cartons, as well as when lettuce was vacuum precooled after packaging in open bags. Vacuum precooling of PE-lined cartons of lettuce did not further delay deterioration, since the process of vacuum cooling eliminated the modified atmosphere previously produced in PE liners. The efficacy of PE-lined cartons and that of closed PE bags in delaying deterioration of lettuce was related to reduction of O2 and accumulation of CO2 in the ambient atmosphere in the package. Concentrations of CO2 in PE-lined cartons, which reached 8 to 12% at the end of holding at 18 to 20°C following storage at 1°C, had no adverse effect on romaine lettuce. However, about 64% of the heads of ‘Great Lakes’ lettuce packed in similar packages during cold storage showed CO2 damage, even when CO2 was not higher than about 3%.

Acceptability of Microwave Reheated Precooked Chicken After Packaging, Freezing and Storing

Chicken pieces were breaded and precooked in corn oil under pressure, individually packaged, frozen, stored for three months, reheated in a microwave oven and evaluated by a taste panel. Variations in freezing rates were accomplished by freezing in air −37°C. (air blast) or with Freon®-12 (−42°C). Packaging variables included bulk packaging in polyethylene bags; packaging individual pieces in Saran-Mylar-laminate pouches before and after freezing; air packaging in aluminum trays with coated paper lids; and coating pieces with acetylated monoglyceride, followed by packaging in aluminum trays. Storage variables included constant −18°C. and fluctuating temperatures.The microwave reheated pieces were equally acceptable when bulk packed in polyethylene bags or vacuum packaged in Saran-Mylar laminated pouches. Results were similar for those frozen by air-blast or using Freon®-12. Air packaged pieces had significantly lower juiciness, flavor and general acceptability scores than pieces from other packaging treatments, and those held at constant temperature had significantly higher scores than did those held under fluctuating temperatures.

Self‐heating and ignition of chemically activated carbon

AbstractFollowing the occurrence of fires in chemically activated carbon in transit, a study has been made of the self‐heating and ignition properties of this material.Thermal ignition theory has been applied to the results of laboratory scale self‐ignition experiments and has enabled realistic prediction of critical sizes of pile for self‐heating to ignition at ordinary ambient temperatures. However, predictions of times to ignition at ordinary temperatures are much larger than found in practice.A distinction emerges between a long‐term self‐heating process responsible for the observed ignition of the ‘weathered’ carbon and short‐term processes which probably include the establishment of moisture equilibrium with the atmosphere and which are largely completed during the standard ‘weathering’ time of 8 days. The long‐term process is not affected by this weathering but is dependent on the temperature of carbonisation and weathering at elevated temperatures (e.g. 100°C).Safe carriage of the carbon in economically worthwhile quantities is ensured by packing in polyethylene bags. These can sustain a small amount of damage with impunity.

THE PACKAGING OF TOMATO JUICE IN COMPLEX MATERIALS

This paper presents the experimental results for the packaging of tomato juice in bags that are made from complex plastic materials, through some preservation processes. The product is packaging in bags made from the complex plastic material PA / PVDC (polyamide / polyvinylidene chloride). In such a material, the products preserved their characteristics – sensorial, physic-chemical and microbiological up to three months.

Ionizing radiation and packaging effects on respiratory behavior, fungal growth, and storage-life of peaches, Prunus persica

Investigations were conducted in 1960 to study effects of fast electron and gamma radiations and packaging films on respiratory rate, control of fungal deterioration, and subsequent refrigeration life of peaches. The fungi responsible for deterioration of peaches were also studied in vitro to determine if they were susceptible or resistant to ionizing (fast electron and gamma) radiations. Respiratory behavior of the fruits under normal as well as modified conditions was assessed with a Claypool and Keefer-type respirometer and Orsat-type gas analyzer. Two kinds of polyethylene films were used for packaging fruits. The fruits after treatments and packaging were stored at 40°F and 85 per cent relative humidity and at 75°F and 35 per cent relative humidity. Effects of ionizing radiations Peaches (var. Elberta) Fast electron and gamma radiation increased respiration and controlled fungus growth. A fungus study in vitro was conducted at ambient (75°F) temperature and relative humidity (35 per cent). The results obtained with fast electron radiation showed that the fungus inhibition effect of radiation was directly proportional to the dosage applied. Effects of ionizing radiations and packaging films Peaches (vars. Elberta and Gem) Peaches (var. Elberta) were packaged in Duratite (type of polyethylene) film and then were irradiated with fast electrons, while peaches (var. Gem) were irradiated with gamma rays before they were packaged in Duratite and another polyethylene film. In fast electron radiation experiments the CO 2 accumulation inside the Duratite bags increased with the increasing radiation dosages; whereas in gamma radiation, dosages applied behaved similarly for both the films except that the levels of CO 2 maintained in polyethylene film were lower than in Duratite film. At radiation dosage of 5 × 10 5 rad, injuries on peaches (var. Gem) were shown as brown areas on the surface of the fruit. Fast electron radiation dosages of 1 × 10 5 and 3 × 10 5 rad were effective in controlling fugus growth and in keeping fruit for longer periods of time than in controls and 5 × 10 5 rad treatment. The evaluation of marketable quality of the fruits in gamma radiation experiments was similar to that obtained with fast electron radiation with the exception that the gamma radiation dosage of 3 × 10 5 rad was best in controlling spoilage by fungi while the fast electron treatment of 1 × 10 5 rad was the best protective dosage. In general, fruits packaged in polyethylene seemed to be better protected than fruits packaged in Duratite bags. The fungi observed on peaches were predominantly Penicillium and Rhizopus species. In general it can be summarized that ionizing radiations (dose 1 to 3 × 10 5 rad) in conjunction with packaging in polyethylene bags increased the refrigerated life of fresh peaches by 15 to 20 days.

Studies on the utilization of persimmons (Diospyros Kaki LINN. f.). V

In the previous paper, it was reported that the most desirable temperature for the storage of fruits of Fuyu variety was 0°C. The present experiment was made to investigate the practical effects of several packing materials on the weight loss and shriveling, growth of microorganisms and lengthening of storage period by maintaining a proper constitution of .atmosphere around the fruit. Post-ripening and, deterioration at room temperature after removal from cold storage were also tested. The sample fruits were obtained from the Kagawa University farm on November 13, and 27, 1958. These fruits were kept at room temperature overnight, then packed and stored on the following day at 0°C and 85_??_90 per cent relative humidity. Seven experimental items were studied: 1. control, 2. packing with excelsior in wooden boxes, 3. packing with rice hull in wooden boxes, 4. packing in sealed desiccators, 5. packing in polyethylene bags of 0.03mm, 6. packing in polyethylene bags of 0.06mm, 7. packing in polyethylene bags of 0. 08mm. The dimensions of polyethylene bags were 14×28 cm and three persimmons were packing in each bag. The results are as follows. 1. The fruits both in polyethylene bags and in desiccators lost only 1 per cent or less of weight, while in control (1), packing with excelsior (2) or with rice hull (3), the loss was 6_??_7 per cent in weight after 2_??_3 months. The fruits became visibly shriveled and spongy-like in its texture when it lost 5 per cent of weight. 2. Carbon dioxide content within the polyethylene bags and desiccators rapidly increased during the early storage period, and reached 5 per cent (in 0.03mm polyethylene bags) to 50 per cent or more (in desiccator) after I month. In the polyethylene bags of 0.08mm and desiccator, the carbon dioxide accumulated to a dangerous level and the fruit showed physiological damage in a longer storage period. 3. The advance of after-ripening and deterioration of Fuyu fruits sealed in the polyethylene bags was slower than that in open bags when moved out to room temperature from the cold storage, and the polyethylene bags of 0.06mm retarded the after-ripening most effectively. 4. On the basis of these results, a temperature of 0°C, relative humidity of almost 100 per cent and combinations of 5 per cent carbon dioxide and 5_??_8 per cent oxygen seem to be the optimum conditions for the storage of Fuyu fruits. The most successful method of storing was to pack them in polyethylene bags of 0.06mm and then to store them at 0°C.

Studies on the utilization of persimmons (Diospyros Kaki L. fil). III

The experiment was made to investigate the effect of storage temperature on keeping period and dessert quality of persimmon fruits, and to determine more desirable storage temperature and the maximum length of time for the fruit to be stored advantageously. At the same time, the effect of packing in polyethylene bags was also studied. Two varieties, Hiratanenashi (astringent variety, harvested on October, 17, 1955) and Fuyu (non-astringent variety, harvested on November, 13, 1955), were tested. One half of these fruits were packed in polyethylene bags of 0.02mm in thickness with dimensions of 12×30cm, three persimmons in each bag. Samples were stored at room temperature, 5°, 0°, and -15°C. The results are as follows. 1. The rate of softening, loss of weight and shriveling, and damages were much more rapid at room temperature than at the lower temperature. The contents of sugar, acid and ascorbic acid in the fruit also decreased rapidly with the increase of the storage temperature, but, when the fruit was kept at -15°C, it showed their gradual but slight decrease over a long period of time. It was noted that the content of soluble tannin was decreased during storage at room temperature, 5 and -15°C, while at 0°C the decrease was very slight. 2. Fruits in polyethylene bags were still in good condition with negligible shriveling and lost only about 1 per cent in weight during five months storage. The concentrations of oxygen and carbon dioxide gas in polyethylene bags were not so different as to compared with the atmosphere because the polyethylene bags used in this experiment was gas permiable. Therefore, they seem to be not so effective so far as the after ripening was concerned. 3. Maximum length of time that the fruits may keep their marketable quality was judged from the texture and the condition of decay. Those were approximately as follows. Hiratanenashi; one month at room temperature, one to two months at 5°C, two to three months at 0°C and throughtout the year at -15°C. Fuyu; two months at room temperature, two to three months at 5°C, three to four months at 0°C and throughtout the year at -15°C. 4. Judging through this experiment, the most desirable storage temperature for Hiratanenashi was found to be about -15°C, because of its fine texture, higher content of sugar, seedless character and the removal of astringency during freezing. For Fuyu, 0°C was found to be favourable.

PRESERVATION OF EGGS: III. STUDIES ON THE EFFECT OF OIL TREATMENT AND EGG-CASE LINER BAGS IN THE PRESERVATION OF SHELL EGGS UNDER ADVERSE CONDITIONS

Three replicate lots of eggs, each divided into half-case (15 doz.) sets on the treatments used, were stored at 70° F. and 90% relative humidity for 35 days. Different sets of eggs were conditioned at 32°, 40°, 60°, and 70° F. before being placed in the humidity chamber, but no resulting effect of initial condensate on the eggs and packaging material was demonstrated.Under the conditions of this experiment, oil treatment by the best commercially applicable method, followed by packaging in sealed egg-case liner bags, was found to retard greatly the development of internal defects and severe external mould. Oil treatment alone was definitely beneficial, but the use of egg-case liner bags on untreated eggs was detrimental. While these experiments show that the method of oil treatment combined with bagging was efficacious in these laboratory scale tests, the results obtained from three small test shipments to Great Britain were not in agreement, and indicated that somewhat different storage conditions may be encountered in the export of shell eggs in non-refrigerated holds. The length of time of storage may also be expected to influence directly the degree of spoilage.Differential spoilage of eggs located in the central and top and bottom trays within the case, and at the periphery and in the interior of individual trays, was also noted under certain conditions. This is considered to indicate the importance of humidity gradients within the case.