Effect of carbon monoxide in modified atmosphere packaging, storage time and endpoint cooking temperature on the internal color of enhanced pork

The objective of this research was to evaluate the effects of gas atmosphere, refrigerated storage time, and endpoint temperature on internal cooked color of injection-enhanced pork chops. Enhanced chops were packaged in 0.36% CO/20.34% CO₂ (CO-MAP), 80% O₂/20% CO₂ (HO-MAP), or PVC-overwrapped (PVC-OW; controls), stored at 4 °C for 0, 12, 19 or 26 days, displayed for 2 days then cooked to six endpoint temperatures (54, 60, 63, 71, 77, and 82 °C). L^*, a^*, and b^* values, hue angle and chroma were determined on the internal cut surface of cooked chops. Chops packaged in CO-MAP had the highest a^* values; a^* value began increasing on day 14. The lowest hue angles occurred in chops cooked to lower endpoint temperatures. Chops in CO-MAP had lower hue angles and higher chroma than those in HO-MAP and PVC-OW. Above 71 °C, hue angle and chroma increased. Overall, CO-MAP packaged chops stored for longer time periods then cooked to lower endpoint temperatures appeared reddest. HO-MAP packaged chops were less red, did not change over time, and appeared more well done at lower endpoint temperatures than those in other gas atmospheres. CO-MAP packaged chops retained redness even after cooking at 82 °C.     

Effect of carbon monoxide and high oxygen modified atmosphere packaging and phosphate enhanced, case-ready pork chops

The objective of this study was to evaluate the effects of CO-MAP compared to traditional high oxygen MAP (HiOx-MAP) packaging and enhanced with different phosphate on enhanced pork quality. Pork loins were enhanced to 10.5% over initial weight to contain 0.3% salt and 0.4% phosphate (either sodium tripolyphosphate [STP] or a blend of STP and sodium hexametaphosphate) on a finished weight basis. Chops were cut, packaged in atmospheres containing 0.4% CO/30.0% CO₂/69.6% N₂ (CO-MAP) or 80% O₂/20% CO₂ (HiOx-MAP), aged in the dark, then placed in a lighted retail display case for 48 h. Chops packaged in CO-MAP were redder (higher Minolta a^* values) and darker (lower Minolta b^* values) than chops packaged in HiOx-MAP. Based on sensory scores, the CO-MAP chops were pinker than the HiOx chops after cooking. CO-MAP chops also experienced less purge loss than chops in HiOx-MAP. Results indicate that CO-MAP had no effect on flavor or consumer acceptability and only minimal effects on other characteristics.     

Effect of carbon monoxide and high oxygen modified atmosphere packaging and phosphate enhanced,case-ready pork chops

The objective of this study was to evaluate the effects of CO-MAP compared to traditional high oxygen MAP (HiOx-MAP) packaging and enhanced with different phosphate on enhanced pork quality. Pork loins were enhanced to 10.5% over initial weight to contain 0.3% salt and 0.4% phosphate (either sodium tripolyphosphate [STP] or a blend of STP and sodium hexametaphosphate) on a finished weight basis. Chops were cut, packaged in atmospheres containing 0.4% CO/30.0% CO₂/69.6% N₂ (CO-MAP) or 80% O₂/20% CO₂ (HiOx-MAP), aged in the dark, then placed in a lighted retail display case for 48 h. Chops packaged in CO-MAP were redder (higher Minolta a¹ values) and darker (lower Minolta b¹ values) than chops packaged in HiOx-MAP. Based on sensory scores, the CO-MAP chops were pinker than the HiOx chops after cooking. CO-MAP chops also experienced less purge loss than chops in HiOx-MAP. Results indicate that CO-MAP had no effect on flavor or consumer acceptability and only minimal effects on other characteristics.     

含CO气调包装对冷却肉肉色的影响

以宰后冷却24h的猪背最长肌为材料,用四组含不同浓度CO的混合气体进行气调包装,于4±1℃下贮藏,分别在第0、5、1O、15、20天测定相关指标。结果表明：CO气调包装能明显改善肉色,并使冷却内在贮藏期中保持稳定的鲜红色。与无氧组相比,CO和O2的共同存在可以使冷却肉肉色更加自然。     

The effect of modified atmosphere packaging with carbon monoxide on the storage quality of master-packaged fresh pork

Modified atmosphere packaging with carbon dioxide is effective for prolonging shelf-life of fresh meat. Addition of carbon monoxide to the system provides the advantage of enhancing meat colour. The study objective was to determine the effect of CO₂-MAP + 0.4% CO, vs. 100% CO₂-MAP, on the bacteriology and colour of retail-ready fresh pork stored for 8 weeks in a master-package system. Total plate counts were not affected and listeria was present on meat from both treatments. Colour was enhanced with the inclusion of CO, while no effect on lipid oxidation was observed. Use of CO in MAP provides sufficient storage life and product colour quality to permit shipment of fresh pork to distant markets. However, given the stable fresh colour of CO-treated meat and the lack of inhibition of pathogen growth by CO, there is concern that CO-MAP under certain conditions may pose a food safety risk.     

含CO气调包装对冷却肉货架期和肉色的影响

以宰后冷却24h的猪里脊肉为材料,用四组含不同浓度CO的混合气体进行气调包装,于4±1℃条件下贮藏,分别在第0、5、10、15、20d测定相关指标.结果表明.CO气调包装可以明显改善肉色,使冷却肉在贮藏期中保持稳定的鲜红色.与无氧组相比,CO和O,的共同存在可以使肉色更加自然.选定的最佳气体配比0.4%CO、24%O:、50%CO2、25.6%N 可以大大改善冷却肉的肉色,并使冷却肉的货架期超过10d.四组处理样品在贮藏到第15d时,TVB-N值超过15mg/100g,细茵总数超过10.cfu/g,各处理对冷却肉的货架期影响差异不显著.     

Evaluation of carbon monoxide treatment in modified atmosphere packaging or vacuum packaging to increase color stability of fresh beef

Our goal was to obtain > 21 days red color stability for carbon monoxide (CO)-treated beef steaks in vacuum packaging (VP). In preliminary tests, pretreatment for 24 h in a 5% CO modified atmosphere package (MAP) was needed to maintain redness after re-packaging in VP. Pressure pretreatment with 5% CO for 2 h developed redness, but was impractical for large-scale application. Color stability and microbial load were then compared after treatment of steaks in 5% CO-MAP for 24 h, then VP; 100% CO-MAP for 1 h, then VP; steaks and ground beef in 0.5% CO-MAP; and steaks and ground beef in polyvinyl chloride (PVC) wrap. Steaks remained red for 5, 6, 8 and <1-week storage at 2°C, respectively. Steaks microbial load exceeded spoilage levels (>10(6)cfu/cm(2)) at 5, 6, 7 and <2-weeks, respectively. Thus, extended color stability in VP was achieved by pretreatment with 5% CO for 24 h or 100% CO for 1 h.     

Effect of vacuum and modified atmosphere packaging on the quality of pork loin

The effect of packaging in protective atmospheres on the process of lipid oxidation, colour and water retention capacity of pork loin chops during refrigerated storage was investigated. The use of modified atmospheres with a high oxygen concentration (70%) acted as a pro-oxidation factor both for fatty acids and for cholesterol (an increase of 86.4% on the initial COPS content). No significant advantages were found in the use of these atmospheres concerning the colour of the meat. Vacuum packaging was seen to be an interesting alternative in the packaging of pork, due to the fact that it increases oxidative stability, which brings about greater colour stability and therefore increases the shelf life. The only disadvantage of this type of packaging is that it increases initial weight loss (5.1% on day 2 of storage).     

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.     

Use of carbon monoxide combined with carbon dioxide for modified atmosphere packaging of pre- and postrigor fresh pork sausage to improve shelf life

Fresh pre- and postrigor pork sausage patties were manufactured in the Iowa State University Meat Laboratory and packaged either in modified atmosphere (MAP) with 0.4% carbon monoxide (CO) and 99.6% carbon dioxide (CO2) or on foam trays overwrapped with oxygen-permeable film (OW). Packages were stored at 2 to 40C under fluorescent lights for up to 31 days. Aerobic, anaerobic, and psychrotrophic plate counts, raw and cooked color, purge, and lipid oxidation were measured during storage. Results indicated that both pork sausage products in MAP had lower aerobic and psychrotrophic counts and less lipid oxidation throughout storage (P < 0.05). Raw color of both products in MAP was redder than the OW patties (P < 0.05), but the prerigor pork sausage in MAP benefited more from the CO atmosphere in terms of raw color than the postrigor pork sausage in MAP. Cooked color of the prerigor pork sausage in MAP was significantly redder than cooked color of the postrigor pork sausage. Both pork sausage products in MAP were also lighter (L* value) than the OW patties for raw and cooked color. Therefore, the combination of CO and CO2 in MAP was beneficial in extending the shelf life of pre-and postrigor fresh pork sausage by reducing aerobic and psychrotrophic microbial growth and improving oxidative stability and color, compared to conventional OW packaging. However, increased purge, increased anaerobic growth, and changes in cooking behavior were also observed for the products in MAP during storage (P < 0.05).     

生物保鲜剂结合气调包装对冷却猪肉品质的影响

以空气包装组为对照,在4℃冷藏条件下,研究了单一保鲜剂（ε-聚赖氨酸）和复合保鲜剂（ε-聚赖氨酸、壳聚糖、茶多酚）分别结合气调包装对冷却猪肉品质的影响。通过测定样品的菌落总数、理化等指标,评价两种保鲜方法结合使用的保鲜效果。结果表明:对照组货架期约为6d,经过ε-PL和复合保鲜剂浸泡处理的冷却猪肉货架期分别为10d和16d。生物保鲜剂结合气调包装能显著延长冷却猪肉货架期,其中,真空包装组比气调组的保鲜效果差;80%CO2+20%O2包装组抑菌以及延缓TVB-N上升的效果最佳,复合保鲜剂组在第20d时还没有超出鲜度标准,但对冷却猪肉色泽有一定的负面影响,且保水性较差;20%CO2+80%O2的抑菌效果在气调组中最差,但对猪肉的色泽有很好的保护作用,复合保鲜剂组保质期约19d;50%CO2+50%O2在抑菌效果、色泽保护以及保水性方面都有很好的效果。      

气调包装中氧气含量对冷鲜猪肉品质的影响

为研究气调包装中氧气含量对冷鲜猪肉贮藏期间品质的影响,采用高阻隔性包装材料及两种不同气体比例(80%O2+20%CO2和50%O2+20%CO2+30%N2)对冷鲜猪肉进行气调包装,以托盘包装为对照,对冷鲜猪肉贮藏期间的菌落总数、色差、保水性、剪切力及包装内气体组成等指标进行检测分析。结果表明:气调包装组能够维持贮藏过程中包装盒内气体成分基本恒定;与托盘包装相比,50%O2气调包装可延长冷鲜猪肉货架期6 d,80%O2气调包装冷鲜猪肉货架期更长;气调包装组冷鲜肉红度值a*、黄度值b*显著高于(P0.05)托盘包装组;气调包装冷鲜猪肉保水性比托盘包装差,而两气调包装组之间无显著差异(P0.05);贮藏过程中气调包装组剪切力值大于托盘包装组(P0.05),80%O2气调包装组剪切力值小于50%O2气调包装组(P0.05);结论:气调包装会对冷鲜猪肉保水性、嫩度等品质造成一些不良影响,但可显著延长其货架期,采用80%O2比50%O2保鲜效果更好。     

Effect of different concentrations of carbon dioxide and low concentration of carbon monoxide on the shelf-life of fresh pork sausages packaged in modified atmosphere

This paper reports the effects of different concentrations of carbon dioxide and the presence of low levels of carbon monoxide on quality attributes throughout storage of fresh pork sausages. Four pork forelegs (initial pH 5.5-5.7) were used to prepare a total of 120 fresh sausages, which were packaged in different atmospheres containing (%O(2)/%CO(2)/%N(2)): 0/20/80; 0/60/40; 40/20/40; 40/60/0; 80/20/0; and 0.3% CO/30% CO(2)/rest argon. The packs were stored for 20 days at 2±1 °C in the dark. Three packs for each atmosphere were opened every 4 days for subsequent analysis of pH, colour CIE L*, a*, b*, TBARS formation, microbial psychotrophic aerobes and sensory discolouration and off-odour. Results showed that increasing concentrations of carbon dioxide promoted oxidation of both myoglobin and lipids, most probably due to its effect of lowering pH. Therefore, preservation of colour and odour of fresh pork sausages packaged in modified atmosphere was better achieved using atmospheres containing low CO(2) concentrations (20%) rather than high (60%). However, their shelf-life depended also on the concentration of O(2); 20% CO(2) with high O(2) (80%) enhanced the red colour, but shortened shelf-life, while 20% CO(2) in the absence of O(2) extended freshness to 16 days. The atmosphere containing 0.3% CO, together with 30% CO(2), maintained the red colour for 20 days, but failed to keep fresh odour longer than 16 days.     

The storage life of beef and pork packaged in an atmosphere with low carbon monoxide and high carbon dioxide

Ground beef, beef loin steaks and pork chops were packaged in modified atmospheres of 0.4% CO/60% CO(2)/40% N(2) and 70% O(2)/30% CO(2). In addition ground beef was packaged in clipped chub packs, beef loin steaks were vacuum packaged, and pork chops were packaged in an atmosphere of 60% CO(2)/40% N(2) with each pack containing an O(2) absorber. The packs were stored in the dark at 4 or 8°C for up to 21 days. Meat in 0.4% CO/60% CO(2)/40% N(2) had a stable bright red colour that lasted beyond the time of spoilage. The storage lives in this gas mixture at 4°C, as limited by off-odours, were 11, 14 and 21 days for ground beef, beef loin steaks and pork chops, respectively. The 70% O(2)/30% CO(2) atmosphere resulted in an initially bright red to red colour of the meat, but the colour was unstable and off-odours developed rapidly. The off-odours probably were caused by Brochothrix thermosphacta, which grew in all meat types, or by pseudomonads in ground beef. Meat stored in chub packs, vacuum packs or 60% CO(2)/40% N(2) with an O(2) absorber developed off-odours and microflora similar to those of meat in 0.4% CO/60% CO(2)/40% N(2), but with less acceptable appearances. These results show that a low CO/high CO(2) atmosphere is effective for preserving retail-ready meat. ?     

Effect of grafting and modified atmosphere packaging on eggplant quality parameters during storage

The physico‐chemical parameters (pH, mechanical firmness and vitamin C) and sensory parameters of grafted and ungrafted eggplant plants were studied in relation to storage time (up to 17 days at 10 °C). Eggplant plants of cultivar ‘Tsakoniki’ were grafted on Solanum torvum and S. sisymbriifolium rootstocks in order to avoid the soil borne disease caused by Verticillium dahliae. The fruits were stored under modified atmosphere packaging (MAP). Vitamin C was negatively affected by grafting it storage, while MAP prolonged the shelf life. Although pH was not affected by grafting but was positively affected by MAP. Flesh firmness was negatively affected by grafting and reduced over storage, but positively affected by MAP. Sensory analysis showed higher ratings of fruits from ungrafted plants for sweetness, acceptance and hardness whereas no difference was detected for overall acceptance. Fruits stored under MAP were better maintained compared with those stored in air.     

不同分割处理对气调包装猪肉贮藏期间品质变化的影响

对猪后腿肌肉分别采用冷分割和热分割处理后进行气调包装,研究了两种处理分割肉在贮藏期间汁液流失率、菌落总数、TVB-N值、pH值和感官指标的变化。结果表明:贮藏期间,冷分割处理的气调包装分割肉在汁液流失率、菌落总数、TVB-N值方面均低于热分处理,冷分割处理可以维持贮藏期间较好的感官指标,但两处理在贮藏期间pH值无显著差异。无论是冷分割处理还是热分割处理的气调包装分割肉,保质期均可达到9d。     

Effect of modified atmosphere packaging and irradiation in combination on content of nitrosamines in cooked pork sausage

The effect of modified atmosphere packaging and irradiation in combination on nitrosodimethylamine (NDMA) and nitrosopyrrolidine (NPYR) levels in pork sausage was studied. Emulsion-type cooked pork sausage was manufactured and packaged in aerobic, CO2 (100%), N2 (100%), and CO2/N2 (25%/75%) environments, respectively, and irradiated at 0, 5, 10, and 20 kGy with gamma irradiation. The nitrosamine contents were significantly reduced by irradiation, and the reduction of nitrosamines was more extensive with modified atmosphere packaging than with aerobic packaging. The correlation coefficient between irradiation dose and nitrosamine content indicated that irradiation can reduce the levels of nitrosamines. The combination of irradiation and modified atmosphere packaging is effective in enhancing the chemical safety of sausage by reducing nitrosamines, if present, as well as enhancing the microbial safety of cooked pork sausage.     

Effect of cooking bag and netting packaging on the quality of pork ham during water cooking

As a preliminary test for combining water cooking with vacuum cooling in soup of pork ham, three package treatments were designed to study the effect of cooking bag and netting on the quality of water cooked ham, i.e. ham cooked with a cooking bag and without a cooking bag (single netting and double netting). For treatments without a cooking bag, the results indicated that there was no significant superiority of ham cooked with double netting compared with ham cooked with single netting on the processing efficiency and quality characteristics. Although the hams cooked with a bag performed better in some chemical retentions and pigment, the water contents were significantly lower than those hams cooked in single netting (P<0.05), and there was a higher shrinkage tendency compared with the hams cooked without a bag. For the processing characteristics and texture properties of pork ham, there were no significant differences observed among the treatments with and without a cooking bag in terms of the combined effect of cooking and cooling (P>0.05). By considering the safety, convenience, cost, and the recovery effect on the quality changes of ham during vacuum cooling in soup, cooking with single netting is a better choice for future research.     

CO气调包装对冷却猪肉货架期及色泽的影响

冷却猪肉采用不同浓度CO气调包装和真空包装,(4±1)℃下贮藏,研究CO气调包装对其货架期和色泽的影响。结果表明,CO气调包装肉在贮藏到第25天时,TVB-N值已超过0.15mg/g,细菌总数超过106cfu/g,与真空包装相比,并不能显著地延长肉的货架期;CO气调包装肉在贮藏期中一直保持稳定的鲜红色,不同浓度CO气调包装对肉色无显著性差异,真空包装肉呈褐色或暗紫色。     

自发气调包装对辣椒贮藏品质的影响

为探究不同自发气调包装对辣椒贮藏品质的影响,以\