Inhibition, survival and growth of Listeria monocytogenes on poultry as influenced by buffered lactic acid treatment and modified atmosphere packaging.

The effect of the treatment with various concentrations (2%, 5% and 10% w/v) of lactic acid/sodium lactate buffer (pH 3.0), modified atmosphere (MAP) packaging (90% CO2 and 10% O2) and 10% (w/v) lactic acid/sodium lactate buffer (pH 3.0) combined with MAP on Listeria monocytogenes Z7 serotype 1 and on the shelf life of chicken legs stored at 6 degrees C was investigated. The initial contamination level of L. monocytogenes on the chicken legs surface was 8.3 x 10(2) cfu/cm2 of skin. After 2 days of storage at 6 degrees C the number of L. monocytogenes on legs treated with 2%, 5%, 10% lactic acid/sodium lactate buffer (pH 3.0) and 10% lactic acid/sodium lactate buffer (pH 3.0) combined with MAP was significantly lower than the initial number of L. monocytogenes. Later, growth of L. monocytogenes was observed. After 13 days of storage at 6 degrees C the number of L. monocytogenes on legs treated with 10% lactic acid/sodium lactate buffer (pH 3.0) combined with MAP was still similar to the initial number. Legs treated with 2%, 5%, 10% lactic acid/sodium lactate buffer (pH 3.0), MAP and 10% lactic acid/sodium lactate buffer (pH 3.0) combined with MAP, have a shelf life at 6 degrees C of respectively 8, 9, 10, 13 and 17 days. This means a prolongation of 2, 3, 4, 7 and 11 days, respectively for storage at 6 degrees C. The antimicrobial effect of lactic acid buffer systems (pH 3.0) increased with increasing concentrations of lactic acid in the buffered system. The best results were obtained by the combined use of 10% acid/sodium lactate buffer (pH 3.0) and MAP.     

Decontamination with lactic acid/sodium lactate buffer in combination with modified atmosphere packaging effects on the shelf life of fresh poultry.

The effect of the treatment with various concentrations (2%, 5%, 7.5% and 10% w/v) of lactic acid/sodium lactate buffer (pH 3.0) combined with modified atmosphere packaging (MAP) (90% CO2/10% O2) on the shelf life and organoleptic quality of fresh chicken legs stored at 6 degrees C was investigated. The CO2 concentration of all samples packed in modified atmosphere (MA) decreased during the first 3 days of storage, followed by a gradual increase after the third day, while O2 showed a corresponding decrease. The buffering capacity of the buffer systems seem to be sufficient to maintain a low pH of the skin during storage. Legs treated with 2, 5, 7.5, and 10% (w/v) lactic acid/sodium lactate buffer (pH 3.0) combined with MAP have a shelf life at 6 degrees C of 14, 15, 16 and 17 days, respectively. The shelf life when the product was not treated with lactic acid was 1, 2.3 and 4 days shorter, respectively.     

Significance of Enterobacteriaceae as index organisms for hygiene on fresh untreated poultry,poultry treated with lactic acid and poultry stored in a modified atmosphere

The significance of colony counts of Enterobacteriaceae on poultry, made at 37°C and at 42°C, and of Escherichia coli, as indicators of hygiene following storage at 6°C was investigated. Untreated chicken legs, legs decontaminated with 10% (w/v) lactic acid buffer, legs packaged in modified atmosphere (MA) and decontaminated (lactic acid buffer) legs packed in MA, were used as model systems.The enumeration of Enterobacteriaceae from plates incubated at either 37°C or at 42°C, indicated the hygienic condition of freshly processed items but not of those that have been stored at 6°C. Enumeration of Escherichia coli constitutes the most realistic means of defining the hygienic condition of poultry after storage of the product at 6°C. Moreover, it was found to be a good indicator of temperature abuse during storage.Decontamination with lactic acid in a buffered solution of 10% (w/v) at pH = 3·0 produced a c. 1 log₁₀ cycle immediate reduction in Enterobacteriaceae colony counts followed by a bacteriostatic effect on the psychrotrophic members of this group amounting to up to 3 log₁₀ during storage at 6°C.     

新疆椒麻鸡中腐败细菌的分离与鉴定

为了探究新疆椒麻鸡腿贮藏期间品质变化并对其货架期进行预测。本文以新疆椒麻鸡腿为研究对象,以酸碱度值（Potential of hydrogen,pH）、色泽、硫代巴比妥酸值（Thiobarbituric acid reactive substances,TBARS）、挥发性盐基氮（Total volatile basic nitrogen,TVB-N）、菌落总数、大肠菌群及感官品质为评价指标,利用加速性破坏实验,研究不同贮藏温度（35 ℃和45 ℃）下椒麻鸡腿的品质变化,以感官得分70分或菌落总数接近国家标准作为货架期终点,并预测出常温（25 ℃）下椒麻鸡腿的货架期。结果表明：不同贮藏温度下的椒麻鸡腿随着贮藏时间的不断延长,pH呈先下降后上升趋势,L^*值整体呈下降趋势,而a^*值、b^*值、TBARS值、TVB-N含量和菌落总数均呈上升趋势,感官评分则不断下降,在贮藏期且45 ℃的变化速率高于35 ℃,在35 ℃贮藏温度下,理论货架期为24 d,在45 ℃贮藏温度下,理论货架期为9 d,在货架期终点样品品质出现不可接受的损失。根据Q₁₀模型计算出Q₁₀=2.6,根据模型预测出常温（25 ℃）条件下理论货架期为62 d。

     

Inhibitory effect of oxalic acid on bacterial spoilage of raw chilled chicken

Oxalic acid was evaluated as a treatment for reducing populations of naturally occurring microorganisms on raw chicken. Raw chicken breasts were dipped in solutions of oxalic acid (0, 0.5, 1.0, 1.5, and 2.0%, wt/vol) for 10, 20, and 30 min, individually packed in oxygen-permeable polyethylene bags, and stored at 4 degrees C. Total plate counts of aerobic bacteria and populations of Pseudomonas spp. and Enterobacteriaceae on breasts were determined before treatment and after storage for 1, 3, 7, 10, and 14 days. The pH and Hunter L, a, and b values of the breast surface were measured. Total plate counts were ca. 1.5 and 4.0 log CFU/g higher on untreated chicken breasts after storage for 7 and 14 days, respectively, than on breasts treated with 0.5% oxalic acid, regardless of dip time. Differences in counts on chicken breasts treated with water and 1.0 to 2.0% of oxalic acid were greater. Populations of Pseudomonas spp. on chicken breasts treated with 0.5 to 2.0% oxalic acid and stored at 4 degrees C for 1 day were less than 2 log CFU/g (detection limit), compared with 5.14 log CFU/g on untreated breasts. Pseudomonas grew on chicken breasts treated with 0.5% oxalic acid to reach counts not exceeding 3.88 log CFU/g after storage for 14 days. Counts on untreated chicken exceeded 8.83 log CFU/g at 14 days. Treatment with oxalic acid caused similar reductions in Enterobacteriaceae counts. Kocuria rhizophila was the predominant bacterium isolated from treated chicken. Other common bacteria included Escherichia coli and Empedobacter brevis. Treatment with oxalic acid caused a slight darkening in color (decreased Hunter L value), retention of redness (increased Hunter a value), and increase in yellowness (increased Hunter b value). Oxalic acid has potential for use as a sanitizer to reduce populations of spoilage microorganisms naturally occurring on raw chicken, thereby extending chicken shelf life.     

Effect of various chemical decontamination treatments on natural microflora and sensory characteristics of poultry

Regulation (EC) No. 853/2004 of the European Parliament and of the Council provides a legal basis permitting the use of antimicrobial treatments to remove surface contamination from poultry. This paper reports the results of research into the effects on natural microflora, pH, and sensorial characteristics achieved by dipping chicken legs (15 min, 18+/-1 degrees C) into solutions (wt/vol) of 12% trisodium phosphate (TSP), 1200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), 220 ppm peroxyacids (Inspexx 100; PA), and water. Samples were collected immediately after evisceration, subjected to the treatments listed or left untreated (control) and tested after 0, 1, 3 and 5 days of storage (3 degrees C+/-1 degrees C). For most microbial groups similar counts were observed on water-dipped and on untreated legs. All the chemical compounds were effective in reducing microbial populations throughout storage, with TSP, ASC and CA showing the strongest antimicrobial activity. The average reductions (mean+/-standard deviation) relative to untreated samples caused by chemical treatments when considering simultaneously all storage days ranged (log(10) cfu/g skin) from 0.53+/-0.83 (PA) to 1.98+/-0.62 (TSP) for mesophilic aerobic counts, from 0.11+/-0.89 (PA) to 1.27+/-1.02 (CA) (psychrotrophs), from 1.34+/-1.40 (PA) to 2.15+/-1.20 (CA) (Enterobacteriaceae), from 1.18+/-1.24 (PA) to 1.98+/-1.16 (CA) (coliforms), from 0.66+/-0.99 (PA) to 1.86+/-1.80 (TSP) (Micrococcaceae), from 0.54+/-0.74 (TSP) to 2.17+/-1.37 (CA) (enterococci), from 0.72+/-0.66 (TSP) to 2.08+/-1.60 (CA) (Brochothrix thermosphacta), from 0.78+/-1.02 (PA) to 1.99+/-0.96 (TSP) (pseudomonads), from 0.21+/-0.61 (PA) to 1.23+/-0.60 (TSP) (lactic acid bacteria), and from 1.14+/-0.89 (PA) to 1.45+/-0.61 (ASC) (moulds and yeasts). The microbial reductions throughout storage increased, decreased, or did not vary, in accordance with microbial group and chemical involved. Similar pH values were observed for untreated samples and for those dipped in PA and water on all sampling days. ASC-treated samples showed a lower pH than controls to day 1. TSP-treated legs exhibited the highest pH values and CA-treated ones the lowest, throughout storage. Hedonic evaluation (nine-point structured scale, untrained panellists) showed similar colour, smell and overall acceptability scores for dipped and untreated samples on day 0 and day 1. From day 3 sensorial attributes scored lower for untreated, PA- and water-dipped legs, as compared to legs treated with TSP, ASC and CA. Only for these three groups of samples were average scores higher than 6 (shelf-life limit value) observed by the end of storage. Results from the present study suggest that the treatments tested improve the microbial quality of chicken without adverse sensorial effects.     

Control of Microbial Spoilage on Fresh Poultry using a Combination Potassium Sorbate/Carbon Dioxide Packaging System

The effects of potassium sorbate combined with vacuum or carbon dioxide modified atmosphere packaging on natural poultry spoilage flora were examined. Fresh chicken thighs were dipped into either 2.5% potassium sorbate solution or distilled water, adjusted to pH 6.0 and packaged on trays in Nylon/Plexar/Surlyn bags. Atmospheres of either air, vacuum or 100% C0₂ were created in the packages which were then stored at 10 ± 1°C for 10 days. Changes in aerobic plate counts, lactic acid bacteria and pseudomonads were monitored. The combination of CO₂ packaging and sorbate treatment provided the most effective inhibitory system against the poultry spoilage organisms, especially Pseudomonas species, without creating a selective environment for the growth of lactic acid bacteria and premature souring of the product. The shelf life of the sorbate/CO₂ samples was extended 3 days over the control/air samples at 10°C.     

Storage Stability of Chicken as Affected by Map and Lactic Acid Treatment

The effects of MAP and/or pretreatment with lactic acid buffer were studied on the shelf-life of broiler carcasses, under conditions simulating market storage (4 and 7°C) in the State of Kuwait. Pretreatment with lactic acid buffer increased treated carcass shelf-life by 6–7 days when stored at 4°C and 5–6 days at 7°C. Likewise, pretreatment of MAP carcasses with the same buffer extended the shelf-life to >36 and 35 days, compared with 22 and 13 days for the untreated MAP carcasses. Pretreatment of poultry with lactic acid buffer, with or without MAP, provides a potential alternative for improving the storage quality of poultry.     

Effects of Trisodium Phosphate and Sodium Chloride Dipping on the Microbial Quality and Shelf Life of Refrigerated Tray-packaged Chicken Breasts

Effects of trisodium phosphate (TSP) and/or sodium chloride (NaCl) dipping on microbial quality and shelf life of chicken breasts were investigated during refrigeration. Chicken breasts were dipped in aqueous solution (w/v) of 10% TSP, 10% NaCl, combination of TSP and NaCl (7.5% + 7.5%) or distilled water (control) for 10 min, followed by tray-packaging storage at 2 degrees C. During storage, chicken breasts dipped in TSP maintained almost constant pH, while pH of control or NaCl-treated samples significantly increased (P<0.05). TSP dipping resulted in initial reduction of 0.48 and 0.91 log(10) CFU/g in aerobic plate counts and Enterobacteriaceae count, respectively, when compared with control. By storage day 6, APC of control chicken breasts reached 6.91 log(10) CFU/g, while TSP-treatment either alone or in combination with NaCl significantly delayed microbial growth (P<0.05) and extended shelf life of refrigerated chicken breasts up to 12 days, at which APC were 6.87 and 6.39, respectively, versus 9.58 log(10) CFU/g for control. Significant reductions in psychrotrophic and Enterobacteriaceae count were detected at the end of storage period in chicken breasts treated with TSP alone or in combination with NaCl, whereas such treatments had no significant effects on lactobacilli or mold and yeast populations.     

Shelf life of beef from local Spanish cattle breeds stored under modified atmosphere

Beef steaks from six Spanish cattle breeds (Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, Rubia Gallega and Retinta) were packaged under modified atmosphere (60% O(2), 30% CO(2) and 10% N(2)). Water loss, pH, thiobarbituric acid values (TBA), aerobic plate counts, lactic acid bacteria and Enterobacteriaceae counts, CIE L*a*b* colour values and the sensory properties of odour and colour were recorded before packaging (day 0) and after 5, 10 and 15 days of storage. A significant interaction (P<0.05) between breed and storage time was found for all variables, except water loss. Values of pH were between 5.3 and 5.6; maximum water loss (2.64%) was reached after 10 days of storage; aerobic plate counts, lactic acid bacteria and Enterobacteriacea counts were lower than 10(7) CFU/g, and L* increased with storage time while a* decreased (P<0.05). The maximum shelf life of beef assessed by sensory evaluation (regarding colour and odour degradation) was between days 5 and 10 in meat from Retinta breed and between days 10 and 15 in meat from the other breeds, shelf life was probably limited by lipid oxidation.     

Survival and growth of Escherichia coli O157:H7, Yersinia enterocolitica and Salmonella enteritidis on decontaminated and untreated meat

Decontamination of meat or carcasses may have an effect in reducing the number of pathogens. Recontamination with other pathogens during cutting or packaging may, however, result in higher growth on decontaminated than on untreated meat due to the lack of competing non-pathogenic microorganisms. In this study we compared the growth of pathogens during storage at 10°C (worst case condition) on untreated meat and meat that had been decontaminated by steam vacuuming combined with spraying with 0.2 M lactic acid. Salmonella enteritidis inoculated on chicken multiplied quickly and reached log 7 cfu per cm(2) after 4 days of aerobic storage at 10°C, but growth was not significantly higher on decontaminated than on untreated chicken. The number of Yersinia enterocolitica inoculated on decontaminated pork skin reached log 9 cfu per cm(2) after 5 days of aerobic storage at 10°C. Overall, growth on vacuum-packed decontaminated and untreated pork under the same conditions was not significantly different, although there tended to be less growth on the untreated samples. The number of Escherichia coli O157:H7 on decontaminated beef increased by nearly 3 log cycles after 5 days of aerobic storage at 10°C compared to only a 1 log cycle increase on untreated beef. For the vacuum-packed beef, growth of E. coli O157:H7 on the fresh meat was very slow, while there was about a 3 log increase on the decontaminated beef. A higher average growth on the decontaminated beef was also found in an experiment with a very low inoculum (27 cfu per cm(2)). During storage of vacuum-packed samples there was multiplication of E. coli O157:H7 on the decontaminated beef, but virtually none on the untreated beef. This study shows that multiplication of S. enteritidis on chicken and Y. enterocolitica on pork skin was not significantly higher on decontaminated compared to untreated meat. The increased multiplication of E. coli O157:H7 on decontaminated beef, especially when vacuum-packed, gives cause for concern. Preventive measures might be a strict HACCP approach to the handling of the decontaminated meat before packaging or use of a protective culture of lactic acid bacteria.     

Effects of chlorine dioxide, cetylpyridinium chloride, lactic acid and trisodium phosphate on physical, chemical and sensory properties of ground beef

The impact of beef trimmings treated with either 0.5% cetylpyridinium chloride (CPC), 200-ppm chlorine dioxide (CLO), 2% lactic acid (LA) or 10% trisodium phosphate (TSP) and an untreated control (C) prior to grinding, on instrumental color, sensory characteristics, TBARS values, pH and Lee-Kramer shear under simulated retail display were evaluated. Trimmings were ground, pattied and sampled at 0, 1, 2, 3 and 7 days of display. Patties from LA, CPC and CLO treatments were lighter (L*; P<0.05) and TSP patties were redder (a*; P<0.05) than C. Panelists found TSP and CPC patties were similar or superior in beef and off odor to C on days 3 and 7 of display. Therefore, treatment of beef trimmings before grinding with TSP, CPC, CLO or LA may not only improve ground beef safety, but maintain or enhance patty shelf life.     

Effect of low-dose radiation on microbiological, chemical, and sensory characteristics of chicken meat stored aerobically at 4 degrees C

The effect of gamma-radiation (0.5, 1, and 2 kGy) on the shelf life of fresh skinless chicken breast fillets stored aerobically at 4 degrees C was evaluated. Microbiological, chemical, and sensorial changes occurring in chicken samples were monitored for 21 days. Irradiation reduced populations of bacteria, i.e., total viable bacteria, Brochothrix thermosphacta, lactic acid bacteria (LAB), and the effect was more pronounced at the highest dose (2 kGy). Pseudomonads, yeasts and molds, and Enterobacteriaceae were highly sensitive to gamma-radiation and were completely eliminated at all doses. Of the chemical indicators of spoilage, thiobarbituric values for nonirradiated and irradiated aerobically packaged chicken samples were in general low (<1 mg of malonaldehyde per kg of muscle) during refrigerated storage for 21 days. With regard to volatile amines, both trimethylamine nitrogen (TMA-N) and total volatile basic nitrogen (TVB-N) values for nonirradiated aerobically packaged chicken increased steeply, with final values of ca. 20.3 and 58.5 mg N/100 g of muscle, respectively. Irradiated aerobically packaged chicken samples had significantly lower TMA-N and TVB-N values (P < 0.05) of ca. 2.2 to 3.6 and 30.5 to 37.1 mg N/100 g of muscle, respectively, during refrigerated storage for 21 days. Of the biogenic amines monitored, only putrescine and cadaverine were detected in significant concentrations in both nonirradiated and irradiated chicken samples, whereas histamine formation was noted only in nonirradiated samples throughout storage. On the basis of sensorial evaluation, low-dose irradiation (0.5 and 1.0 kGy) in combination with aerobic packaging extended the shelf life of fresh chicken fillets by ca. 4 to 5 days, whereas irradiation at 2.0 kGy extended the shelf life by more than 15 days compared with that of nonirradiated chicken.     

Bacteriological quality of broiler carcasses as affected by in-plant lactic acid decontamination

In an attempt to improve the bacteriological quality of broiler carcasses the bactericidal effect of treatments with 1% and 2% lactic acid was investigated. Bacterial colonisation was determined immediately after treatment, after the carcasses had been chilled and during storage at 0 degrees C. Examination included numbers of mesophilic aerobic and psychrotrophic aerobic colony-forming units (CFU), CFU of Enterobacteriaceae at 37 degrees C and CFU of Staphylococcus aureus. Immediately after treatment colonisation per gram skin was generally reduced by about 1 log. Initially 2% lactic acid was not found significantly more effective in reducing colony counts than 1%. However, treatment with 2% lactic acid suppressed post-decontamination colonisation with Enterobacteriaceae more effectively than 1% lactic acid, as determined after 15-18 days storage at about 0 degrees C. Lactic acid treatment was most effective when applied shortly before chilling. Successive treatment at three different stages during slaughtering did not increase reduction of colony counts. It is concluded that decontamination with 1-2% lactic acid at pH 2, when applied shortly before chilling, will markedly improve the bacterial safety and increase the refrigerated shelf life of broiler carcasses.     

Microbiological,colour and sensory changes of refrigerated chicken legs treated with selected phosphates

The influence of dipping chicken legs for 10 min in 5% solutions containing monopotassium phosphate (MKP), monosodium phosphate (MSP), sodium pyrophosphate (SPP), or trisodium phosphate (TSP) on aerobic plate counts (APC), Hunter colour, odour, and appearance of chicken legs were assessed. TSP had greater antimicrobial activity than MKP, SPP or MSP. Chicken legs treated with 5% TSP for 10 min had aerobic plate counts nearly 3 logs lower than controls and other treatments after 12 days of storage at 4°C. Shelf-life of legs could be extended to 16 days with 7.5 or 10% TSP treatment. TSP-treated legs were darker, less red, and less yellow than untreated legs. TSP-treated legs had a detectable chemical odour at levels greater than 10%; however, at 5% TSP, treated legs had odour and appearance resembling fresh controls for up to 16 days at 4°C. Dipping chicken legs in 5–10% TSP could extend shelf-life up to 8 days during refrigerated storage without adversely affecting sensory quality.     

Decontamination of deboned chicken legs by vacuum-tumbling in lactic acid solution

Vacuum tumbling in a 1–5% lactic acid solution for a short time (1–10 min) improves the microbiological quality of deboned chicken legs, while inducing a light acidification and water absorption. The most significant variable of the process is the tumbling speed. High tumbling speeds lead to a high decontamination level of the chicken legs with regard to total viable counts and Enterobacteriaceae. Sodium lactate alone is unable to induce any decontamination at the same concentrations. Decontamination is probably more linked to acidification than to lactate ions. The use of vacuum tumbled (1 min in a 1% lactic acid solution) deboned chicken legs in the industrial manufacture of fresh chicken sausages led to a clear decrease in the number of Salmonella‐positive batches. The incidence of positive batches was reduced threefold and the acid decontamination process did not adversely affect the sensory quality of the sausages.     

The effects of conditioning on meat collagen: Part 4-The use of pre-rigor lactic acid injection to accelerate conditioning in bovine meat

Injection of fresh bovine muscle with 0·1 m lactic acid (to a level of 10% of original muscle weight) resulted in a pH decline to a minimum pH of 5·33 at 15°C only 3 h after injection. Untreated muscle reached the same pH after 26 h when held at the same temperature. Fresh, unconditioned meat colour was unaffected by pre-rigor 0·1 m lactic acid injection as assessed by visual inspection. The percentage of perimysial collagen extracted as the soluble form was significantly higher (P < 0·05) from three muscles of varying quality when pre-injected with 0·1 m lactic acid and conditioned from 1 to 14 days, than from conditioned untreated muscles. SDS-polyacrylamide gel electrophoresis of CNBr peptides from insoluble perimysium obtained from three muscles of varying quality revealed no obvious differences due to pre-rigor lactic acid injection before conditioning. However, analysis of the high molecular weight perimysial collagen CNBr peptides from lactic acid treated muscles by two-dimensional SDS-polyacrylamide gel electrophoresis revealed an increased incidence of degradation in this region compared with untreated controls. These data strongly suggest that pre-rigor injection of beef muscle with lactic acid may accelerate conditioning. The implications of this finding are discussed.     

白胡椒和肉桂对冰鲜鸡的保鲜效果研究

以冰鲜鸡的菌落总数、挥发性盐基氮、pH、感官质量作为保鲜效果评价指标,研究了不同浓度的白胡椒和肉桂醇溶提取液处理冰鲜鸡在0～4℃贮藏的保鲜效果。结果表明,白胡椒和肉桂的醇溶提取液在冰鲜鸡中有显著的保鲜作用,其中1.0%白胡椒和1.0%肉桂保鲜效果较好,可明显降低样品菌落总数和挥发性盐基氮(TVB-N)并有效控制pH值上升,样品在10天仍有较好的感官指标,可延长保质期7天。     

The microbiology and storage stability of vacuum packed lamb

Lamb joints (shoulders, loins and legs) stored in vacuum packs at 0–1°C remained unspoiled for 6 weeks, but since the aerobic storage life at 5°C (retail shelf life) of lamb after holding in vacuum packs at 0–1°C for 6 weeks was only 2 days, vacuum storage should be limited to a maximum of 4 weeks in practice. Brochothrix thermosphacta , Moraxella spp, and Moraxella-like organisms were predominant on aerobically spoiled lamb and the preservative effect of vacuum packing resulted from the inhibitory effects of the high carbon dioxide (>20%) and low oxygen concentrations (<1%) which developed in the packs. Brochothrix thermosphacta was not completely inhibited, however, and with lactic acid bacteria was the possible cause of cheesy/sour odours which terminated vacuum packed storage life.     

复合保鲜剂对冷鲜肉货架期的影响

采用复合保鲜剂1%醋酸+3%柠檬酸+0.1%抗坏血酸和1%醋酸+1%乳酸+0.2%茶多酚对冷却肉进行处理,分别在0、3、6、9天测定样品的菌落总数、大肠菌群和挥发性盐基氮,并对样品的颜色和感官性状进行评价。结果表明:复合保鲜剂1%醋酸溶液+1%乳酸+0.2%茶多酚可使鲜肉在第6天时,菌落总数、大肠菌群、挥发性盐基氮在鲜肉要求范围之内,并且感官状态良好,该复合试剂能够达到延长冷鲜肉货架期的目的。