Maintenance of safety and quality of refrigerated ready-to-cook seasoned ground beef product (meatball) by combining gamma irradiation with modified atmosphere packaging

Abstract: Meatballs were prepared by mixing ground beef and spices and inoculated with E. coli O157:H7, L. monocytogenes, and S. enteritidis before packaged in modified atmosphere (3% O₂+ 50% CO₂+ 47% N₂) or aerobic conditions. The packaged samples were irradiated at 0.75, 1.5, and 3 kGy doses and stored at 4 °C for 21 d. Survival of the pathogens, total plate count, lipid oxidation, color change, and sensory quality were analyzed during storage. Irradiation at 3 kGy inactivated all the inoculated (approximately 10⁶ CFU/g) S. enteritidis and L. monocytogenes cells in the samples. The inoculated (approximately 10⁶ CFU/g) E. coli O157:H7 cells were totally inactivated by 1.5 kGy irradiation. D¹⁰‐values for E. coli O157:H7, S. enteritidis, and L. monocytogenes were 0.24, 0.43, and 0.41 kGy in MAP and 0.22, 0.39, and 0.39 kGy in aerobic packages, respectively. Irradiation at 1.5 and 3 kGy resulted in 0.13 and 0.36 mg MDA/kg increase in 2‐thiobarbituric acid‐reactive substances (TBARS) reaching 1.02 and 1.49 MDA/kg, respectively, on day 1. Irradiation also caused significant loss of color and sensory quality in aerobic packages. However, MAP effectively inhibited the irradiation‐induced quality degradations during 21‐d storage. Thus, combining irradiation (3 kGy) and MAP (3% O₂+ 50% CO₂+ 47% N₂) controlled the safety risk due to the potential pathogens and maintained qualities of meatballs during 21‐d refrigerated storage. Practical Application: Combined use of gamma irradiation and modified atmosphere packaging (MAP) can maintain quality and safety of seasoned ground beef (meatball). Seasoned ground beef can be irradiated at 3 kGy and packaged in MAP with 3% O₂+ 50% CO₂+ 47% N₂ gas mixture in a high barrier packaging materials. These treatments can significantly decrease risk due to potential pathogens including E. coli O157:H7, L. monocytogenes, and S. enteritidis in the product. The MAP would reduce the undesirable effects of irradiation on quality, and extend the shelf life of the product for up to 21 d at 3 °C.     

In vitro application of selected essential oils and their major components in controlling fungal pathogens of crown rot in Embul banana (Musa acuminata– AAB)

The necessity for pesticide‐free fresh produce have prompted investigating the effect of selected essential oils and their major components on inhibition of conidial germination, appressoria formation and membrane permeability changes of the pathogens responsible for crown rot of banana. Eugenol, which is the major component of the essential oil of Ocimum basilicum, was the most effective chemical component in inhibiting conidial germination of Colletotrichum musae and Fusarium proliferatumin vitro while Cymbopogon citratus oil was the least effective. Both O. basilicum and C. citratus oils and their major components (Eugenol, citral a + b) inhibited appressoria formation by C. musae and changed the selective permeability of conidial membranes. Ocimum basilicum oil, eugenol and citral a + b could be satisfactorily used for inhibition of conidial germination and disruption of conidial activity of banana pathogens.     

Extending storage life of fresh ginseng by modified atmosphere packaging

Fresh ginseng (Panax ginseng) was packaged with LDPE and PVC films. The respiration rates of fresh ginseng were determined in modified atmosphere packaging (MAP) at 0, 10 and 20 °C. The changes in chemical compositions were also measured before and after storage. The results showed that respiration rates of fresh ginseng were suppressed more effectively in MAP, especially in a poly(vinyl chloride) (PVC) package. The storage life of fresh ginseng was significantly extended with better appearance and firmness for 210 days. The decay rate was only 1.3% and 1.0% in both low density polyethylene (LDPE) and PVC film package after 210 days of storage at 0 °C, respectively. The results of saponin analysis indicated that the contents of total saponin were not changed much in all treatments. Reducing sugar was increased by 2.7 to 5.3 times, while pectin decreased by 1.1 to 1.4 times after 210 days of storage at the range of 0–20 °C. Total sugar content also increased during storage, especially in LDPE packages and high temperature. It was considered that MAP was very effective storage method for keeping quality better with minimal quality loss and lower decay rate at lower temperature. Copyright © 2005 Society of Chemical Industry     

Shelf life extension of lamb meat using thyme or oregano essential oils and modified atmosphere packaging

The effect of thyme (TEO) and oregano (OEO) essential oils as well as modified atmosphere packaging (MAP) in extending the shelf life of fresh lamb meat stored at 4 °C was investigated. In a preliminary experiment TEO and OEO were used at concentrations 0.1 and 0.3% v/w while MAP tested included MAP1 (60% CO(2)/40% N(2)) and MAP2 (80% CO(2)/20% N(2)). Microbiological, physicochemical and sensory properties of lamb meat were monitored over a 20 day period. Sensory analysis showed that at the higher concentration both essential oils gave a strong objectionable odour and taste and were not further used. Of the two essential oils TEO was more effective as was MAP2 over MAP1 for lamb meat preservation. In a second experiment the combined effect of TEO (0.1%) and MAP2 (80/20) on shelf life extension of lamb meat was evaluated over a 25 day storage period. Microbial populations were reduced up to 2.8 log cfu/g on day 9 of storage with the most pronounced effect being achieved by the combination MAP2 plus TEO (0.1%). TBA values varied for all treatments and remained lower than 4 mg MDA/kg throughout storage. pH values varied between 6.4 and 6.0 during storage. Color parameters (L and b) increased with storage time while parameter (a) remained unaffected. Based primarily on sensory analysis (odour) but also on microbiological data, shelf life of lamb meat was 7 days for air packaged samples, 9-10 days for samples containing 0.1% of TEO and 21-22 days for MAP packaged samples containing 0.1% TEO.     

涩柿MAP保鲜技术研究

软化和褐变是柿果保鲜两大技术难题,实验以桂林涩柿为材料,研究(0±0.3)℃下,在不同贮运保鲜期高压PE膜、微孔PE膜、KMS膜(自制防雾PE膜)等MAP的保鲜效果,定期检测果肉硬度(FF)、可溶性固形物(SSC)、可滴定酸含量(TA)、褐变指数(BI)和好果率。结果表明:桂林柿果MA贮藏120d,KMS膜保鲜效果最好,袋内气体浓度达到平衡时,O2为5.5%、CO2为7.0%,FF为11.14kg/cm2,SSC为12.91%,TA为0.59%,BI增加了0.72,好果率为82.9%,均显著优于对照。     

Novel approach to oxygen control in modified atmosphere packaging of bakery products

PDA plates inoculated with mould spores were packaged in air and in a mixture of CO₂/N₂ (60 : 40) with headspace oxygen adjusted to range from <0·05% to 10% (v/v) and stored at 25°C. Those packaged in air showed mould growth after 1–1·5 d, while those in the gas mixture showed growth between 4–6 d after headspace oxygen reached a minimum concentration of 0·4%. Uninoculated plates packaged in air showed no change in headspace oxygen concentration over 30 d at 25°C, while those in the gas mixture with initial headspace oxygen of <0·05% showed a steady increase of oxygen, through packaging film permeability, at an average rate of 0·06%/d. If uninoculated plates were packaged in air together with a sachet of oxygen absorbant called Ageless, the headspace oxygen was quickly reduced to <0·05% within 9 h and remained unchanged thereafter.Crusty rolls with a_w of 0·95 and pH of 5·62 developed mould after 5–6 d when packaged in air, 9–11 d in 100% N₂ and 16–18 d in CO₂/N₂ (60 : 40). However, when Ageless was incorporated into all the packages the product remained mould free for >60 d. This study shows that oxygen absorbants offer the bakery industry a viable alternative to gas flushing.     

气调包装对番石榴贮藏品质的影响

研究12℃时4%O2+5%CO2+91%N2的气调包装对番石榴贮藏品质的影响。与相同温度下未气调包装相比,气调包装能够延缓果实的软化,推迟果肉内过氧化物酶活性和还原糖含量的达峰时间,降低了VC和可滴定酸的分解速率,抑制了丙二醛的生成速率。结果表明,气调包装的番石榴保质期比未气调样品延长了一倍,其在番石榴贮藏保鲜中有一定的推广应用价值。     

Sprouting and quality control of fresh ginger rhizomes by modified atmosphere packaging with film perforation

The quality of ginger rhizomes packaged in low density polyethylene bags (modified atmosphere packaging — MAP) without perforations (P-0), with 2 perforations (P-2), and 12 perforations (P-12) have been investigated for 5 months at 12±1°C. Sprouting and rotting rates of ginger in P-2 and P-12 were lower than ginger in P-0. Weight loss was higher in P-12 than P-0 and P-2. Surface L* (lightness) and a* (redness) values in P-2 and P-12 were lower and higher, respectively, than those found for P-0. Sensory appearance and overall acceptability were rated significantly better in P-2 and P-12 than in P-0. Internal color, firmness, soluble solids, and pH of ginger in MAP were not affected by presence of perforations. Therefore, MAP with the appropriate number of perforations (in this work, 2 perforations) could be a useful method to control sprouting and maintain quality except for surface color of stored ginger rhizomes.     

Gas exchange in modified atmosphere packaging. 2: Experimental results with strawberries

Strawberries were used to test a new model describing gas transport through micro-perforated polypropylene films and fruit respiration involved in modified atmosphere packaging. Some experiments were conducted with empty packs initially filled with either 100% N₂ or 100% O₂. Simulations agreed very well with experiments only if we replaced the cross-sectional area of the micro-perforations by areas of approximately half the actual areas in order to account for the resistance of air around the perforations. It is also possible to fit the model to gas concentration changes in packs filled with strawberries, although deviations have been due to the contamination of strawberries by fungi. the model was used to quantify the consequences of the variability of pack properties (number of micro-perforations per pack and cross-sectional area of these perforations) on equilibrium gas concentrations and to define minimum homogeneity requirements for modified atmosphere packaging.     

Shelf life of ready to use peeled shrimps as affected by thymol essential oil and modified atmosphere packaging

In this work the influence of different packaging strategies on the shelf life of ready to use peeled shrimps was investigated. First, the effectiveness of the coating (Coat) and the active coating loaded with different concentrations of thymol (Coat-500, Coat-1000, and Coat-1500) on the quality loss of the investigated food product packaged in air was addressed; afterwards, the thymol concentration that had shown the best performance was used in combination with MAP (5% O₂; 95% CO₂). Microbial cell load of main spoilage microorganisms, pH and sensorial quality were monitored during the refrigerated storage. Results of the first step suggested that the sole coating did not affect the microbial growth. A slight antimicrobial effect was obtained when the coating was loaded with thymol and a concentration dependence was also observed. Moreover, the active coating was effective in minimizing the sensory quality loss of the investigated product, it was particularly true at the lowest thymol concentration. In the second step, the thymol concentration (1000 ppm) that showed the strike balance between microbial and sensorial quality was chosen in combination with MAP. As expected, MAP significantly affected the growth of the mesophilic bacteria. In particular, a cell load reduction of about 2 log cycle for the samples under MAP respect to that in air was obtained. Moreover, the MAP packaging inhibited the growth of the Pseudomonas spp. and hydrogen sulphide-producing bacteria. The MAP alone was not able to improve the shelf life of the uncoated samples. In fact, no significant difference between the control samples packaged in air and MAP was observed. Whilst, the use of coating under MAP condition prolonged the shelf life of about 6 days with respect to the same samples packaged in air. Moreover, when the MAP was used in combination with thymol, a further shelf life prolongation with respect to the samples packaged in air was observed. In particular, a shelf life of about 14 days for the active coating under MAP compared to the same samples in air (5 days) was obtained.     

Active packaging of cheese with allyl isothiocyanate, an alternative to modified atmosphere packaging

The natural antimicrobial compound allyl isothiocyanate (AITC), found in mustard oil, is effective against cheese-related fungi both on laboratory media and cheese. Penicillium commune, Penicillium roqueforti, and Aspergillus flavus were more sensitive to AITC when it was added just after the spores had completed 100% germination and branching had started on Czapek yeast extract agar than were spores in the dormant phase. The use of 1 AITC label (Wasaouro interior labels, LD30D, 20 by 20 mm) in combination with atmospheric air in the packaging extended the shelf life of Danish Danbo cheese from 4 1/2 to 13 weeks. Two AITC labels extended the shelf life from 4 1/2 to 28 weeks. Both 1 and 2 labels in combination with modified atmosphere packaging extended the shelf life of the cheese from 18 to 28 weeks. This study showed that AITC was absorbed in the cheese, but it was not possible to detect any volatile breakdown products from AITC in the cheese. Cheese stored for up to 12 weeks with an AITC label had an unacceptable mustard flavor. The mustard flavor decreased to an acceptable level between weeks 12 and 28. Cheese stored in atmospheric air had a fresher taste without a CO2 off-flavor than did cheese stored in modified atmosphere packaging. AITC may be a good alternative to modified atmosphere packaging for cheese. The extended shelf life of cheese in the package is very desirable: the cheese can be transported longer distances, and the packaging can be used for the final maturing of the cheese. Furthermore, AITC can address problems such as pinholes and leaking seals in cheese packaging.     

Responses of CA-stored Bramley's Seedling and Cox's Orange Pippin apples to modified atmosphere retail packaging

The responses of Bramleys and Coxs apples to modified atmosphere (MA) retail packaging were studied in samples of fruit removed from controlled-atmosphere (CA) storage at monthly intervals through the marketing season, packed in MA or perforated control packs and held under simulated marketing conditions at 15C. The degree of modification of the pack atmospheres and the effects of MA packaging on fruit ripening changes were influenced by the duration and conditions of storage prior to packing. In addition, differential effects of MA packaging on the extent of retardation of flesh softening and skin yellowing were found as the storage period was extended. During 2 or 4 weeks at 15C, however, MA packs made from low density polyethylene (LDPE, 30 p) were effective in retarding changes in firmness and skin colour of Bramleys, previously stored for < 22 weeks (October-March) in 8% C02+ 13% O2 or for < 30 weeks (October-May) in 6% C02+3% 02. Similarly, during a 2-week marketing period at 15C, LDPE or ethylenevinylacetate (EVA, 30 II.) MA packs were effective in retarding some ripening changes in Coxs previously stored for < 31 weeks (Oc- tober-May) in < 1% C02+1.25% 02. The practical benefits of MA retail packaging for the marketing of apples are also discussed.     

Combined effect of natural essential oils, modified atmosphere packaging, and gamma radiation on the microbial growth on ground beef

Selected Chinese cinnamon, Spanish oregano, and mustard essential oils (EOs) were used in combination with irradiation to evaluate their ability to eliminate pathogenic bacteria and extend the shelf life of medium-fat-content ground beef (23% fat). Shelf life was defined as the time when the total bacterial count reached 10(7) CFU/g. The shelf life of ground beef was determined for 28 days at 4 degrees C after treatment with EOs. The concentrations of EOs were predetermined such that sensory properties of cooked meat were maintained: 0.025% Spanish oregano, 0.025% Chinese cinnamon, and 0.075% mustard. Ground beef samples containing EOs were then packaged under air or a modified atmosphere and irradiated at 1.5 kGy. Ground beef samples (10 g) were taken during the storage period for enumeration of total mesophilic aerobic bacteria, Escherichia coli, Salmonella, total coliforms, lactic acid bacteria, and Pseudomonas. Mustard EO was the most efficient for reducing the total mesophilic aerobic bacteria and eliminating pathogenic bacteria. Irradiation alone completely inhibited the growth of total mesophilic aerobic and pathogenic bacteria. The combination of irradiation and EOs was better for reducing lactic acid bacteria (mustard and cinnamon EOs) and Pseudomonas (oregano and mustard EOs). The best combined treatment for extending the shelf life of ground beef for up to 28 days was EO plus irradiation (1.5 kGy) and modified atmosphere packaging.     

Preservation of precut white cheese by modified atmosphere packaging

Effects of modified atmosphere packaging (MAP) on storage stability and quality of precut fresh and aged white cheese were investigated. Fresh or aged white cheese was cut into small cubes and packaged in five different atmospheres [0% O₂ + 0% CO₂ + 100% N₂ (MAP1), 10% O₂ + 0% CO₂ + 90% N₂ (MAP2), 0% O₂ + 75% CO₂ + 25% N₂ (MAP3), 10% O₂ + 75% CO₂ + 15% N₂ (MAP4) and aerobic (air)]. Control samples were packaged in brine and vacuum for fresh and aged white cheese, respectively. Changes in gas composition, total plate count, lactococci, lactobacilli, yeast and mould counts, proteolysis, lipolysis, pH, colour, texture and sensory properties were investigated during refrigerated storage. The best packaging treatment for the fresh cheese was MAP3, as it inhibited mould growth and protected the hardness. MAP2 can be recommended for the packaging of the aged cheese, as it decreased lipolysis.     

Combination of bulk storage in controlled and modified atmospheres with modified atmosphere packaging system for chilled whole gutted hake

Whole gutted hake placed in boxes of ice were kept in modified and controlled atmospheres for 12 days with the gas mixture 60%CO₂/15%O₂/25%N₂ (v/v/v) at 2 ± 1 °C. Each lot of hake was then subdivided into two other lots and these were packed on trays, some of them in air and some in the same mixture of gases. The trays were kept at 2 °C until spoilage. The shelf‐life of the hake stored in these conditions was assessed by physical (pH), chemical (TVBN (total volatile basic nitrogen) and TMA‐N (trimethylamine nitrogen)) and sensory (inspection and taste panel) analyses. The results of these analyses indicated that the control lot (stored in air throughout) was rejected before the lots kept in adjusted atmospheres. However, the taste panel accepted all the lots, including the control lot, after 24 days of storage. The sample which was kept at 2 °C in a controlled atmosphere for 12 days and then packed in a modified atmosphere of the same gas mixture did not exceed pH 7 after 31 days of storage, nor the limits of TVBN and TMA‐N of 40 and 12 mg per 100 g respectively. As regards oxidative rancidity, TBA (2‐thiobarbituric acid) levels were very low under all storage conditions and did not exceed 2.5 mg malonaldehyde per 100 g muscle. According to the results of this study, bulk storage of whole gutted hake in boxes in ice under a controlled atmosphere could be combined with later packaging in a modified atmosphere on trays stored at 2 °C to extend the shelf‐life of the hake. © 2001 Society of Chemical Industry     

The extension of the shelf-life of 'pesto' sauce by a combination of modified atmosphere packaging and refrigeration

Summary This study was intended to extend, by optimizing modified atmosphere packaging (MAP), the shelf-life of the Italian vegetable sauce used for spaghetti and known as 'pesto'. A mathematical model was developed in order to predict gas composition inside the polymeric package (CO₂ concentration). Predictions of equilibration time and equilibrium gas composition showed moderately good agreement with experimental data. A useful extension of pesto shelf-life, up to 120 days, was achieved by adopting a target atmosphere containing, at steady-state, 10% CO₂ and 90% N₂ at 5 °C. Microbial growth was inhibited by the CO₂ levels, but was not accompanied by significant changes in odour and colour.     

Thymol and modified atmosphere packaging to control microbiological spoilage in packed fresh cod hamburgers

A study on the use of mild technologies to produce packaged fish hamburgers was presented. In particular, the antimicrobial effect of some natural compounds (carvacrol, eugenol, thymol, green tea extract, rosemary extract, grapefruit seed extract and lemon extract), at various concentrations (500–10 000 ppm), was screened in vitro against the main fish spoilage micro‐organisms (Shewanella putrefaciens and Photobacterium phosphoreum). Lemon extract and thymol, in combination with modified atmosphere packaging, showed the greatest inhibition activity, therefore, thymol was subsequently used as an ingredient for producing fish hamburgers. Results pointed out that this combination is effective in controlling the growth of microbial species mainly involved in fresh fish spoilage; in particular, it significantly (P < 0.05) reduced the growth rate of bacterial population, performing about 4.8 log CFU g^?1 and 6.5 log CFU g^?1 reduction of the hydrogen sulphide producing bacteria and psychrotrophic aerobic specific spoilage organisms cell load, respectively, if compared with the control.     

Effect of irradiation and modified atmosphere packaging on the microbiological safety of minced pork stored under temperature abuse conditions

The safety of irradiated pork packed in 25% CO₂:75% N₂ and stored at abuse temperature (10 or 15°C) was assessed by inoculation studies involving Salmonella typhimurium, Listeria monocytogenes, Escherichia coli, Yersinia enterocolitica and Clostridium perfringens . Irradiation to a dose of 1.75 kGy reduced pathogen numbers to below the detection limit of 10² cells g^-1. When higher inoculum levels were used (10⁶ cells g^-1) irradiation at 1.75 kGy reduced pathogen numbers by 1 –>5 log₁₀ cycles depending on strain. Clostridium perfringens was the most resistant, and Y. enterocolitica the most sensitive of the pathogens studied.
In all cases when high numbers (10⁶ to 10⁷g^-1) of spoilage and/or pathogenic bacteria were present initially on the pork the meat appeared spoiled, and although irradiation reduced the number of microorganisms, the meat was still unacceptable from a sensory viewpoint after treatment.
It was concluded that the microbiological safety of irradiated, modified atmosphere packaged (MAP) pork is better than that of unirradiated MAP pork.