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1.
Gillian A. Francis & David O'Beirne 《International Journal of Food Science & Technology》1998,33(5):465-476
A solid-surface model system was used to study the effects of gas atmospheres encountered in modified atmosphere packaging of vegetables on the survival and growth of Listeria monocytogenes and competing micro-organisms. The effects of increasing CO2 levels (from 5% to 20%), 100% N2 and 3% O2 were determined. The model system allowed for estimation of the growth of L. monocytogenes alone or in the presence of competing microflora. CO2 concentrations of 5–10% (with 5% O2 in N2 ) had no inhibitory effect, by comparison with air, on the growth and survival of pure cultures of L. monocytogenes . At 20% CO2 population densities were reduced up to day 8, but the final population densities reached were not. An atmosphere of 100% N2 allowed survival of pure cultures of L. monocytogenes , but populations did not significantly change ( P > 0.05) during storage, whereas a low O2 (3%, balance N2) atmosphere allowed significant growth ( P < 0.05) of L. monocytogenes . Growth and inhibitory activities of Enterobacter cloacae and E. agglomerans were inversely related to the concentration of CO2 . By contrast, the growth and anti-listerial activities of Leuconostoc citreum increased with elevated CO2 concentrations. In the low O2 atmosphere, L. monocytogenes grew considerably better in the presence of populations from the indigenous microflora of lettuce than when in pure culture. The results indicate that the gas atmospheres present within modified atmosphere packages of minimally processed vegetables may affect the interactions between the pathogen and the natural competitive microflora sufficiently to indirectly enhance L. monocytogenes growth. 相似文献
2.
Gillian A. Francis & David O'Beirne 《International Journal of Food Science & Technology》2001,36(5):477-487
The survival and growth of Listeria monocytogenes and L. innocua on ready-to-use (RTU) packaged vegetables (lettuce, swedes, dry coleslaw mix, bean-sprouts) were studied. The effects of acid adaptation of Listeria spp. on their survival during subsequent storage were also investigated. Listeria innocua behaviour was similar to that of L. monocytogenes on all vegetables examined. The survival and growth patterns of Listeria varied with the packaged product. Populations on packaged lettuce and swedes significantly increased ( P < 0.05, by 1–1.5 log cycles) during a 14-day storage period. During the same period, Listeria counts gradually decreased (by 1–1.5 log cycles) on coleslaw mix. Acid adaptation enhanced survival of Listeria spp. during storage in packages of vegetables which had relatively high in-pack CO2 levels (i.e. 25% in packaged coleslaw, bean-sprouts). It is concluded that adapting listerial cells to mildly acidic conditions rendered cultures more resistant to relatively high (25–30%) CO2 atmospheres. 相似文献
3.
Modified atmosphere packaging of shredded lettuce 总被引:1,自引:0,他引:1
A. BALLANTYNE R. STARK J. D. SELMAN 《International Journal of Food Science & Technology》1988,23(3):267-274
A retail package system was used to study the atmosphere modification which developed within packages of shredded Iceberg lettuce, sealed in trays with a range of polymer films of different gas permeabilities (oxygen permeability of 3000 to 10,000 ml/m2 /day/atm. at 25°C). Modified atmospheres were produced both naturally by respiration, and by application of gas flushing techniques.
The effects of these modified atmosphere conditions on visual and sensory quality of shredded lettuce was observed by monitoring colour change and development of off-odours. An equilibrated modified atmosphere containing 1–3% O2 and 5–6% CO2 was established with 35 um low density polyethylene film after flushing with 5% O2, 5% CO2 in N2 . This resulted in a shelf-life of approximately 14 days at 5°C, almost double that of the controls. 相似文献
The effects of these modified atmosphere conditions on visual and sensory quality of shredded lettuce was observed by monitoring colour change and development of off-odours. An equilibrated modified atmosphere containing 1–3% O
4.
ABSTRACT: Listeria monocytogenes , a psychrotrophic foodborne pathogen, is a recurring postprocess contaminant on ready-to-eat meat (RTE) products including frankfurters. Flash (Steam) Pasteurization (FP) and ultraviolet light (254 nm-UVC) has been shown to reduce levels of L. monocytogenes and L. innocua on frankfurters. In this study, the use of UVC light followed by FP to inactivate L. innocua, a nonpathogenic surrogate for L.monocytogenes , on frankfurters that contained sodium diacetate and potassium lactate (SDA/PL) in a pilot-plant setting was investigated. Application of UVC (1.0 J/cm2 ), followed by FP (0.75 s steam/121 °C) resulted in inactivation of 3.19 log L. innocua , while application of UVC (4.0 J/cm2 ), followed by FP (3 s steam/121 °C) resulted in inactivation of 3.89 log of L. innocua . A refrigerated storage study (8 °C) of frankfurters that contained SDA/PL that were treated with UVC followed by FP revealed the growth of L. innocua was inhibited for approximately 8 wk following application of the interventions. The use of UVC in combination with FP had little effect on frankfurter color and texture. The combination of UVC, FP, and SDA/PL was found to be an effective hurdle process for decontamination of frankfurter surfaces. 相似文献
5.
Rong Y. Murphy R.E. Hanson N.R. Johnson L.L. Scott N. Feze K. Chappa 《Journal of food science》2005,70(2):M138-M140
ABSTRACT: This study was to evaluate the effectiveness of steam or steam in combination with an antimicrobial agent to control Listeria monocytogenes on ready-to-eat (RTE) franks. The franks were surface-inoculated to contain 6 or 3 log10 (colony-forming units [CFU])/cm2 of L. monocytogenes and treated with steam or steam in combination with an antimicrobial agent, immediately followed by vacuum-sealing the top films of frank packages (6 franks per package in a single layer). Three log (CFU) /cm2 of reductions were achieved at the both inoculation levels for L. monocytogenes on franks. At an inoculation level of 3 logs, no outgrowth of L. monocytogenes was obtained on the treated franks after storing at 4.4°C or 16°C for a combined 47 d. This study provided an alternative approach for controlling L. monocytogenes in packaged franks. 相似文献
6.
Microwave Oven Heating for Inactivation of Listeria Monocytogenes on Frankfurters before Consumption
Mawill Rodríguez-Marval Ifigenia Geornaras Patricia A. Kendall John A. Scanga Keith E. Belk John N. Sofos 《Journal of food science》2009,74(8):M453-M460
ABSTRACT: Microwave oven heating was evaluated for inactivation of Listeria monocytogenes on inoculated and stored frankfurters. Frankfurters formulated without/with 1.5% potassium lactate and 0.1% sodium diacetate were inoculated with L. monocytogenes (1.9 ± 0.2 log CFU/cm2 ), vacuum-packaged, and stored (4 °C) to simulate conditions prior to purchase by consumers. At storage days 18, 36, and 54, packages were opened and placed at 7 °C, simulating aerobic storage in a household refrigerator. At 0, 3, and 7 d of aerobic storage, 2 frankfurters were placed in a bowl with water (250 mL) and treated in a household microwave oven at high (1100 W) power for 30, 45, 60, or 75 s, or medium (550 W) power for 60 or 75 s. Frankfurters and the heating water were analyzed for total microbial counts and L. monocytogenes populations. Exposure to high power for 75 s reduced pathogen levels (0.7 ± 0.0 to 1.0 ± 0.1 log CFU/cm2 ) to below the detection limit (<−0.4 log CFU/cm2 ) on frankfurters with lactate/diacetate, even after 54 d of vacuum-packaged storage followed by 7 d of aerobic storage. For frankfurters without lactate/diacetate, high power for 75 s caused reductions between > 1.5 and 5.9 log CFU/cm2 from control levels of 1.5 ± 0.1 to 7.2 ± 0.5 log CFU/cm2 . Depending on treatment and storage time, the water used to reheat the frankfurters had viable L. monocytogenes counts of <−2.4 to 5.5 ± 0.5 log CFU/mL. The results indicated that frankfurters should be reheated in a microwave oven at high power for 75 s to inactivate up to 3.7 log CFU/cm2 of L. monocytogenes contamination. 相似文献
7.
Effects of the indigenous microflora of minimally processed lettuce on the survival and growth of Listeria innocua 总被引:1,自引:0,他引:1
Gillian A. Francis & David O'Beirne 《International Journal of Food Science & Technology》1998,33(5):477-488
Interactions between the natural background microflora of shredded lettuce and Listeria innocua (in lieu of Listeria monocytogenes ) were studied. The effect of increasing the initial size of indigenous populations (from 103 to 106 –107 CFU g−1 ) was tested for its ability to reduce L. innocua growth on shredded lettuce. Co-culture experiments were performed in model media, where bacterial isolates from the indigenous microflora were tested for possible inhibitory effects. Varying the size of the indigenous populations had no effect on L. innocua survival or growth. However, interactions with individual species and mixed populations from lettuce did affect the survival and growth of L. innocua in model media. In general, mixed populations diminished L. innocua growth. In the undiluted lettuce medium, the various species tested individually either reduced or did not affect the growth of L. innocua . However, when the medium was diluted, some species extended the survival of L. innocua . Competition between the indigenous microflora and L. innocua resided mostly with the Enterobacter spp. and not with the pseudomonads. Enterobacter cloacae was particularly effective in reducing L. innocua growth. Lactic acid bacteria also reduced L. innocua growth in undiluted media. It is concluded that interactions with the natural background microflora may play an important role in determining the dynamics of Listeria populations on shredded lettuce. 相似文献
8.
R.R. Boyer K. Matak S.S. Sumner B. Meadows R.C. Williams J.D. Eifert W. Birbari 《Journal of food science》2009,74(5):M219-M223
ABSTRACT: Listeria monocytogenes is the pathogen of concern in ready-to-eat (RTE) meat products. Salt brines are used to chill processed meats. L. monocytogenes and lactic acid bacteria (LAB) can grow under saline conditions, and may compete with each other for nutrients. The objective of this study was to determine the effect of lactic acid bacteria ( Enterococcus faecalis , Carnobacterium gallinarum , and Lactobacillus plantarum ) on the survival of L. monocytogenes and Listeria innocua in brines stored under low temperatures for 10 d. Sterile tap water (STW) and 2 brine solutions (7.9% and 13.2% NaCl) were inoculated with 1 of 5 cocktails ( L. monocytogenes , L. innocua , LAB, L. monocytogenes + LAB, or L. innocua + LAB) at initial concentrations of 7 log CFU/mL. Brines were stored for 10 d at 4 or 12 °C. Three replications of each brine concentration/cocktail/temperature combination were completed. No significant reductions of L. monocytogenes occurred in 7.9%[w/v] or 13.2%[w/v] brines when LAB were present; however, there were significant reductions after 10 d of L. monocytogenes in the STW solution when LAB were present (1.43 log CFU/mL at 4 °C and 3.02 log CFU/mL at 12 °C). L. innocua was significantly less resilient to environmental stresses of the brines than L. monocytogenes , both with and without LAB present ( P ≤ 0.05). These strains of lactic acid bacteria are not effective at reducing L. monocytogenes in brines at low temperatures. Furthermore, use of L. innocua as a model for L. monocytogenes is not appropriate under these environmental conditions. 相似文献
9.
ABSTRACT: Listeria monocytogenes , a psychrotrophic foodborne pathogen, is a recurring postprocess contaminant on ready-to-eat meat (RTE) products, including frankfurters. Potassium lactate (PL) and sodium diacetate (SDA) are FDA-approved antimicrobials that inhibit the growth of L. monocytogenes when incorporated into the formulation of fine emulsion sausage. Flash (steam) pasteurization (FP) has been shown to reduce levels of L. monocytogenes , and its surrogate L. innocua , on frankfurter surfaces. The ability of FP to inactivate and prevent the growth of the L. monocytogenes surrogate L. innocua in a pilot plant setting was investigated. FP treatment (1.5 s, 121 °C) of single layers of frankfurters that were surface-inoculated with either 5, 4, or 3 log CFU/g of L. innocua immediately before FP (1.5 s, 121 °C) resulted in log reductions of 1.97 (± 0.11), 2.03 (± 0.10), or 2.07 (± 0.14), respectively. Inoculum level had no effect on the inactivation of L. innocua . Following 8 wk of refrigerated storage (4 °C), L. innocua levels decreased by 0.5 log in non-FP-treated frankfurter packs, while the 2 log reduction of L. innocua was maintained for FP-treated frankfurters. FP (1.5 s, 121 °C) had no effect on frankfurter color or texture. Because the numbers of L. monocytogenes associated with contaminations of ready-to-eat meats are typically very low, the use of FP in combination with PL and SDA has the potential to reduce the number of frankfurter recalls and foodborne illness outbreaks. 相似文献
10.
Shaowei Liu Virenda M. Puri & Ali Demirci 《International Journal of Food Science & Technology》2009,44(1):29-35
The suitability of Listeria innocua for use as an indicator for replacing Listeria monocytogenes during the cheese-making and ripening of Camembert cheese was evaluated. Pasteurized whole milk inoculated with either L. innocua or L. monocytogenes was used to make Camembert cheese, which were ripened in three stages. All cheese was ripened in three stages: room temperature (∼20 °C) and relative humidity of 60% for 36 h; 12 °C and relative humidity of 93% for 2 weeks; and 7 °C and relative humidity of 85% for 3 weeks. Results showed that population values of L. innocua and L. monocytogenes on day 1 were 7.16 and 6.11 log10 CFU/g, respectively, which declined to 6.54 and 5.45 log10 CFU/g, respectively, during subsequent 20 days. Thereafter, L. innocua and L. monocytogenes populations increased to 7.38 and 6.06 log10 CFU/g on day 35 of ripening, respectively. During ripening, surface and interior of cheeses were analysed for populations of L. innocua and L. monocytogenes , respectively. The data were collected on day 1, 5, 10, 15, 20, 25, 30, and 35 of ripening. Generally, the growth of L. innocua and L. monocytogenes is faster in surface than in centre. Top centre, bottom centre and bottom surface locations had similar population values during ripening. There were no significant differences ( P > 0.05) between batch and section of cheese. The ripening time and locations had significant effect ( P < 0.05) on the survival and growth of L. innocua and L. monocytogenes . The trends of survival and growth of L. innocua and L. monocytogenes were similar. These results indicated that L. innocua can be considered as an indicator for L. monocytogenes during ripening of Camembert cheese. 相似文献
11.
Friedly EC Crandall PG Ricke S O'Bryan CA Martin EM Boyd LM 《Journal of food science》2008,73(4):M174-M178
ABSTRACT: Listeria innocua M1 has been used by many researchers as a nonpathogenic thermal processing surrogate for Listeria monocytogenes . However, L. innocua M1 has been criticized because its thermal survivability characteristics are not as closely parallel to L. monocytogenes as some would like in a variety of foods and processing conditions. The present study was conducted to compare multiple L. innocua and L. monocytogenes strains to validate L. innocua M1 as the ideal surrogate under high-temperature thermal processing conditions for L. monocytogenes . The D - and z -values of L. innocua M1, L. innocua strain SLCC 5639 serotype (6a), SLCC 5640 (6b), SLCC 2745 (4ab), and L. monocytogenes F4243 (4b) were calculated for raw hamburger patties. Hamburger patties were inoculated with 107–8 CFU/g of L. monocytogenes or L. innocua . Samples were heat treated at 4 temperatures (62.5 to 70 °C). At each temperature, the decimal reduction time ( D -value) was obtained by linear regression of survival curves. The D - and z -values were determined for each bacterium. The D -values of L. innocua and L. monocytogenes serotypes ranged from 3.17 to 0.13 min at 62.5 to 70 °C, and the z -values of L. innocua and L. monocytogenes were 7.44 to 7.73 °C. Two of the 4 L. innocua serotypes used in this experiment have the potential for use as surrogates in hamburger meat with varying margins of safety. L. innocua M1 should serve as the primary nonpathogenic surrogate with the greatest margin of safety in verifying a new thermal process to destroy L. monocytogenes . 相似文献
12.
Chemical and sensory changes in haddock and herring stored under modified atmosphere 总被引:2,自引:1,他引:2
SANNEGOWDA DHANANJAYA GEOFFREY D. STROUD† 《International Journal of Food Science & Technology》1994,29(5):575-583
The effectiveness of storage in atmospheres with increased proportions of CO2 to extend the shelf-life of haddock and herring was examined. Using a 40: 30: 30/CO2 : O2 : N2 atmosphere with haddock no useful extension of shelf-life was achieved at +5°C and only limited extension at 0°C. A more useful extension of shelf-life at 0°C was obtained by storing haddock in a 60: 20: 2O/CO2 : O2 : N2 atmosphere and with herring in a 60:40/CO2 ::N2 : atmosphere. Total volatile bases (TVB) and hypoxanthine values (Hx) correlated with the cooked flavour. There were no significant differences in drip-loss between the modified atmosphere packaging (MAP) stored samples and the controls. Peroxide values (PV) in herring were lower in MAP stored samples. Whole haddock and whole herring were found to have a longer shelf-life when stored in MAP at 0°C than when stored as fillets. 相似文献
13.
ABSTRACT: The impact of sodium nitrite (NaNO2 ) on detection and recovery of Listeria monocytogenes from select ready-to-eat (RTE) foods including smoked salmon, smoked ham, beef frankfurters, and beef bologna was assessed. Nitrite-containing (NC; 100 to 200 ppm NaNO2 ) or nitrite-free (NF) foods were inoculated with a 5-strain cocktail of L. monocytogenes by immersion into Butterfield's buffer solution containing 5.4 to 7.4 × 103 L. monocytogenes per milliliter. Inoculated products were vacuum-packaged and stored at 5 °C. A weekly comparative analysis was performed for presence of L. monocytogenes using 5 detection methods on products held at 5 °C for up to 8 wk. L. monocytogenes initially present at <100 CFU/g during the first 2 wk of storage increased throughout the study, attaining final populations of approximately 1 × 104 to 1 × 105 CFU/g. Lactic acid bacteria predominated throughout the study in all products. Exposure to NaNO2 (100 to 200 ppm) resulted in 83% to 99% injury to the L. monocytogenes strains tested. The genetic-based BAX® System (DuPont™ Qualicon, Wilmington, Del., U.S.A.) and modified USDA/FSIS methods detected 98% to 100% of Listeria -positive food samples and were consistently superior to and significantly different ( P < 0.05) from conventional cultural methods in recovering Listeria from NC samples. Data show that nitrite-induced injury adversely affects detection and recovery of L. monocytogenes from NC food, confirming earlier findings that nitrite-induced injury masks L. monocytogenes detection in NC RTE food products. Nitrite-injured Listeria can subsequently repair upon nitrite depletion and grow to high levels over extended refrigerated storage. 相似文献
14.
HASAN TEMZ UMUT AYKUT ABDULKADR K HURT 《International Journal of Dairy Technology》2009,62(3):378-386
In this study, the shelf life of Lor cheese stored under different atmosphere compositions was assessed and compared. Lor cheeses were held in four different atmospheres containing: vacuum packaging (VP), 40% CO2 /60% N2 , 60% CO2 /40% N2 and 70% CO2 /30% N2 (modified atmosphere packaging). Control cheeses were stored in air. All cheese samples were kept in the refrigerator at 4°C for 45 days and investigated for physicochemical, microbiological and sensory properties. The acidity index value was significantly higher ( P < 0.05) in the control and vacuum packaged samples than in those stored for the same period under CO2 . Microbiological results showed that modified atmosphere packaging delayed microbial growth compared with air and VP samples. Of the three modified atmospheres, gas mixtures 60% and 70% CO2 were the most effective for inhibition of growth of micro-organisms. Sensory evaluation (odour and taste) results showed that Lor cheese packaged under modified atmosphere packaging (60% CO2 /40% N2 and 70% CO2 /30% N2 ) retained good characteristics for 45 days of storage, while vacuum and control samples were sensorily unacceptable after 10 days of storage. 相似文献
15.
Modeling the Growth Characteristics of Listeria monocytogenes and Native Microflora in Smoked Salmon
ABSTRACT: Smoked salmon contaminated with Listeria monocytogenes has been implicated in foodborne listeriosis. The objectives of this study were to model the growth characteristics and examine the growth relationship of L. monocytogenes and native microflora in smoked salmon. Smoked salmon samples with a native microflora count of 2.9 log10 CFU/g were inoculated with a 6-strain mixture of L. monocytogenes to levels of log10 1.6 and log10 2.8 CFU/g, and stored at 4, 8, 12, and 16 °C. Growth characteristics (lag phase duration [LPD, h], growth rate [GR, log10 CFU/h], and maximum population density [MPD, log10 CFU/g]) of L. monocytogenes and native microflora were determined. At 4 to 16 °C, the LPD, GR, and MPD were 254 to 35 h, 0.0109 to 0.0538 log10 CFU/h, and 4.9 to 6.9 log10 CFU/g for L. monocytogenes , respectively, and were 257 to 29 h, 0.0102 to 0.0565 log10 CFU/h, and 8.5 to 8.8 log10 CFU/g for native microflora. The growth characteristics of L. monocytogenes or the native microflora were not significantly different ( P > 0.05), regardless the initial levels of L. monocytogenes . Mathematical equations were developed to describe the LPD, GR, and MPD of L. monocytogenes and native microflora as a function of storage temperature. The growth relationship between L. monocytogenes and native microflora was modeled and showed that the LPD and GR of L. monocytogenes were similar to those of native microflora. These models can be used to estimate the growth characteristics of L. monocytogenes in smoked salmon, and thereby enhance the microbiological safety of the product. 相似文献
16.
IRENE R. GRANT MARGARET F. PATTERSON 《International Journal of Food Science & Technology》1991,26(5):507-519
The effect of combining low-dose irradiation (1.75 kGy) with modified atmosphere packaging (MAP) on the microbiological and sensory quality of pork chops stored at refrigeration temperatures was studied. The microflora of irradiated MAP pork was almost exclusively composed of lactic acid bacteria, predominantly Lactobacillus spp. Modified atmospheres containing either 25 or 50% CO2 , balance N2 , resulted in the best microbial control in irradiated pork held at 4°C, compared to an unirradiated MAP control, and these atmospheres were subsequently used in sensory studies. The atmosphere containing 25% CO2 75% N2 maintained the uncooked colour and odour of irradiated pork chops more effectively than 50% CO2 50% N2 . Therefore packaging in a modified atmosphere containing 25% CO2 , balance N2 , followed by irradiation to a dose of 1.75 kGy is recommended to improve the microbiological and sensory quality of pork chops. 相似文献
17.
S.B. MANO G.D. GARCIA DE FERNANDO D. LOPEZ-GALVEZ M.D. SELGAS M.L. GARCIA M.I. CAMBERO J.A. ORDOÑEZ 《Journal of Food Safety》1995,15(4):305-319
Listeria monocytogenes was inoculated onto fresh pork and turkey slices. Inoculated and control samples were packaged under modified atmospheres (100% N2 , and 20%/80% and 40%/60% CO2 O2 ) or air in plastic bags of low gas permeability. Samples were stored at 1 and 7C. Samples stored in air showed a similar microbiological pattern to that usually observed in fresh meat stored aerobically. Packaging under modified atmospheres extended the meat shelf-life. Bacterial growth was strongly inhibited at 1C, particularly in samples stored under CO2 /O2 enriched atmospheres. Temperature and pH were critical factors for L. monocytogenes growth. This pathogen grew only on pork (initial pH 5.3) packaged in air and stored at 7C. No L. monocytogenes growth was observed at 1C in any atmosphere assayed. However, growth on turkey (initial pH 6.0) was marked at 7C in all atmospheres tested, while at 1C, this bacterium grew weakly only on samples stored in air . 相似文献
18.
Anlaug Ådland Hansen Turid Mørkøre Knut Rudi Marit Rødbotten Frøydis Bjerke Thomas Eie 《Journal of food science》2009,74(6):M242-M249
ABSTRACT: Pieces of prerigor salmon fillets were packaged in modified atmosphere (60% CO2 and 40% N2 ) and in vacuum. The MA packages had a gas to product volume ratio (g/p ratio) of 3/1 (traditional MAP) and 1/1 (packaged with a CO2 emitter). All the samples were stored at 1.2 °C for 25 d. The MA packages had lower bacterial growth during storage compared to vacuum packages. The analyses of 16S rRNA at day 22 indicated a similar bacterial diversity, independent of packaging methods, dominated by Photobacterium phosphoreum . The results therefore suggest that CO2 inhibited total bacterial count, including, P. phosphoreum . Negative odors and liquid losses were detected earlier for the vacuum-packaged samples (8 d) compared to the MA samples (15 d) and higher levels were detected at the end of the storage period. The breaking strength (firmness) tended to be lower for the MA packaged samples compared with the vacuum samples after 15 d of storage, whereas the redness ( a * value) and the yellowness ( b * value) were significantly higher for the MA samples. In conclusion, MA packaging preserved the quality better during storage than vacuum packaging. MA packaging with a CO2 emitter and reduced g/p ratio gave similar or better results compared with traditional MAP, thus CO2 emitters are well suited for reduction of volume of MA packaged farmed salmon fillet pieces. 相似文献
19.
ABSTRACT: Liquid smoke fractions (S1, S2, S3, and S4) were applied on ready-to-eat (RTE) meat products to control the growth of inoculated Listeria innocua M1. Turkey rolls and roast beef products were dipped in liquid smoke, surface inoculated with L. innocua M1 (102 CFU/25 cm2 RTE meat surface), vacuum packaged, and stored at 4 °C. Section 8.5 of USDA's detection and isolation procedure for L. monocytogenes was employed in conjunction with a Micro-ID™ system for L. innocua M1 identification (ID). Products treated with smoke fractions S1, S2, and S3 were negative for L. innocua M1 at 2 and 4 wk during incubation at 4 °C. Products treated with S4 were positive for L. innocua M1 immediately following inoculation and after storage for 2 and 4 wk. Smoke fractions S1, S2, and S3 exhibited pH values lower than 4.6, acidity values higher than 1.5%, and carbonyl concentrations higher than 110 mg/mL. All liquid smoke fractions contained similar phenol concentrations (0.3 to 0.6 mg/mL), suggesting that phenols may have a limited role in the bactericidal effects of liquid smoke fractions against specific microorganisms. 相似文献
20.
ABSTRACT: Astringent "Rojo Brillante" persimmon fruits were stored in air or in 2 different controlled atmospheres: 10% CO2 + 90% N2 (CA1) or 97 % N2 + air (CA2) for up 50 d at 15 °C. After different periods, the fruit were treated with 95% CO2 for 24 h at 20 °C in order to remove astringency, and then transferred to 20 °C in air free of CO2 for 5 d to simulate shelf life. Other fruits were directly transferred to shelf life without being submitted to deastringency treatment. Storage under CA2 allowed storability of persimmon "Rojo Brillante" during 30 d at 15 °C, maintaining commercial firmness. Moreover, CA2 had an effect on removing astringency when fruits were stored for 30 d at 15 °C, or after 20 d following to shelf life. As consequence, deastringency treatment could be avoided when the fruits were previously stored under this controlled atmosphere. 相似文献