Microbiological and chemical quality of ground beef treated with sodium lactate and sodium chloride during refrigerated storage

The effects of sodium lactate (NaL) and sodium chloride (NaCl), either alone (30 g/kg) or in combination (20+20 g/kg), on the microbiological and chemical quality of raw ground beef during vacuum-packaged storage at 2°C were investigated. The results showed that addition of NaL alone or in combination with NaCl significantly delayed the proliferation of aerobic plate counts, psychrotrophic counts, lactic acid bacteria and Enterobacteriaceae and extended the shelf life of the product up to 15 and 21 days, respectively, versus 8 days only for control. Over the storage time (21 days), NaL maintained the ground beef at almost constant pH, while the pH of control or NaCl-treated samples significantly decreased. Lipid oxidation (TBA value) was not affected by addition of NaL. At storage day 21 however, TBA values of both NaL-treated (0.309) and control (0.318) samples were significantly lower than those of samples treated with NaCl (0.463). The combination of NaCl with NaL significantly reduced the oxidative changes caused by NaCl (0.384 versus 0.463). Therefore, NaL alone or in combination with NaCl could be utilized successfully to reduce the microbial growth, maintain the chemical quality, and extend the shelf life of ground beef during refrigerated storage.     

底物和环境因子对鱼源腐败希瓦氏菌和假单胞菌生长动力学的影响

水产品在贮运和加工过程中极易腐败,微生物是引起腐败的主要原因,腐败希瓦氏菌和假单胞菌分别是低温有氧贮藏海水鱼和淡水鱼时的特定腐败菌。为探讨环境因子和底物对特定腐败菌的影响,以源自大黄鱼和罗非鱼中的腐败希瓦氏菌和假单胞菌为对象,探究不同底物、温度、pH和NaCl影响下的菌体生长动态,采用Gompertz方程拟合生长曲线,定量分析对其最大比生长速率(μ_max)和迟滞期(λ)的影响,并使用Belehradek方程描述其μ_max与温度间的关系。结果表明:底物对腐败希瓦氏菌和假单胞菌生长影响较为明显;而温度对其生长影响最为显著,是影响腐败速率的决定性因素;pH对腐败希瓦氏菌生长影响较大,pH为7时其μ_max高于pH为6时,但对假单胞菌无明显影响,pH为4和5时,两者均不生长;NaCl含量对腐败希瓦氏菌生长有显著影响,随着NaCl含量的升高,其μ_max和λ降低。该研究可为探究水产品腐败菌调控因子筛选、靶向抑菌和延长产品货架期等提供支撑。     

Delayed Clostridium perfringens growth from a spore inocula by sodium lactate in sous-vide chicken products

Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag marinated chicken breast that included 0%, 1.5%, 3%, or 4.8% sodium lactate (NaL; w/w). The packages were processed to an internal temperature of 71.1 degrees C, ice chilled and stored at 4, 19, and 25 degrees C. The total C. perfringens population was determined by plating diluted samples on Tryptose-sulfite-cycloserine agar followed by anaerobic incubation for 48 h at 37 degrees C. At 25 degrees C, addition of 1.5% NaL was effective in delaying growth for 29 h. Increasing the NaL level to 4.8%, C. perfringens growth from a spore inoculum during storage at 25 degrees C for 480 h was not observed. At 19 degrees C, the growth was > 6 log 10 cfu/g by 288 h in control samples. In samples with 3.0% or 4.8% NaL, the growth of C. perfringens from spores was dramatically restricted with little or no growth in 648 h at 19 degrees C. C. perfringens growth was not observed at 4 degrees C regardless of NaL concentration. The D-values at 55 degrees C ranged from 47.40 (no NaL) to 57.58 min (1.5% NaL). Cyclic and static temperature abuse of refrigerated products for 20 h did not permit C. perfringens growth. However, temperature abuse of products for periods 24 h or longer in the absence of NaL led to growth of C. perfringens from a spore inoculum. An extra degree of safety may be assured in such products by supplementation with NaL at 1.5-4.8% NaL level.     

THE EFFECT OF LYSOZYME AND BUTYLATED HYDROXYANIZOLE ON SPOILAGE AND PATHOGENIC BACTERIA ASSOCIATED WITH FOODS

The effect of pH (5 to 7), NaCl concentration (0.5 to 5%) and chelating agents on the antibacterial activity of lysozyme and butylated hydroxyanizole (BHA) was investigated by the Spiral Gradient End Point test. Of all the bacteria tested (including 7 Gram-positive and 8 Gram-negative organisms), lysozyme was active only against Lactococcus lactis NCK 400. When EDTA was added, lysozyme was inhibitory for all of the Gram-positive and 4 of the Gram-negative species. Butylated hydroxyanizole was active against all the organisms tested, except for 2 pseudomonads, but these were inhibited when EDTA was added. The inhibition effected by lysozyme and BHA, both in the presence and absence of EDTA, was greatest at low pH and high NaCl concentrations. The inhibition by lysozyme was unaffected by other chelators (sodium citrate and monoglycerol citrate). However, sodium citrate promoted the inhibitory effect of BHA towards Gram-negative bacteria and monoglycerol citrate lowered the minimum inhibitory concentration required by BHA to inhibit 5 of the 7 Gram-positive bacteria by 10%.     

乳酸钠抑制铜绿假单胞菌生长的机理

为探索乳酸钠(NaL)抑制铜绿假单胞菌(Pseudomonas aeruginosa)生长的机理,从NaL影响目标菌细胞膜(壁)结构完整性和胞内ATP的合成两方面进行了探讨。研究结果表明,0.02 g/mL NaL显著破坏了细胞膜结构的完整性,对照组破坏程度较小,两者差异显著(P<0.05);另一方面,0.02 g/mL NaL抑制了胞内ATP合成,而对照组中ATP含量明显高于NaL试验组(P<0.05)。试验结果为合理、高效利用乳酸钠为新型肉类防腐剂提供了理论依据。     

Sensory, Microbial and Chemical Characteristics of Fresh Aerobically Stored Ground Beef Containing Sodium Lactate and Sodium Propionate

Hamburger patties with sodium lactate (NaL; 0, 3, or 4%) with or without sodium propionate (NaP; 0.1, or 0.2%) were stored aerobically at 4°C for 0, 1, 2, or 3 days, and evaluated for sensory attributes, Aerobic Plate Counts (APCs), lipid oxidation, pH, and water activity. NaL slowed microbial growth; addition of 0.2% NaP to 3% NaL increased antimicrobial effects equal to that of 4% NaL. NaL in combination with NaP reduced lipid oxidation over control or NaL patties. Patties with NaL had higher beef/brothy and beef fat scores and were sweeter, springier, more cohesive, and less crumbly than control patties and addition of 0.2% NaP increased juiciness.     

Evaluation of NaCl,pH, and lactic acid on the growth of Shiga toxin-producing Escherichia coli in a liquid Cheddar cheese extract

A Cheddar cheese model system, Cheddar cheese extract, was used to examine how different levels of known microbial hurdles (NaCl, pH, and lactic acid) in Cheddar cheese contribute to inhibition of bacterial pathogens. This knowledge is critical to evaluate the safety of Cheddar varieties with altered compositions. The range of levels used covered the lowest and highest level of these factors present in low-sodium, low-fat, and traditional Cheddar cheeses. Four pathogens were examined in this model system at 11°C for 6 wk, with the lowest levels of these inhibitory factors that would be encountered in these products. The 4 pathogens examined were Salmonella enterica, Staphylococcus aureus, Listeria monocytogenes, and Shiga toxin-producing Escherichia coli (STEC). None of these organisms were capable of growth under these conditions. The STEC exhibited the highest survival and hence was used to examine which of these inhibitory factors (NaCl, pH, and lactic acid) was primarily responsible for the observed inhibition. The STEC survival was examined in Cheddar cheese extract varying in NaCl (1.2 vs. 4.8%), lactic acid (2.7 vs. 4.3%), and pH (4.8 vs. 5.3) at 11°C for 6 wk. The microbial hurdle found to have the greatest effect on STEC survival was pH. The interactions between pH and levels of protonated lactic acid and anionic lactic acid with STEC survival was also evaluated; only the concentration of protonated lactic acid was determined to have a significant effect on STEC survival. These results indicate that, of the pathogens examined, STEC is of the greatest concern in Cheddar varieties with altered compositions and that pH is the microbial hurdle primarily responsible for controlling STEC in these products.     

Modelling the interactions between Lactobacillus curvatus and Enterobacter cloacae. I. Individual growth kinetics

Mixed cultures of Lactobacillus curvatus and Enterobacter cloacae were chosen as a model system to quantitatively study microbial interactions involved in food spoilage and food preservation. In this paper models were developed to predict the individual behaviour of L. curvatus and E. cloacae in pure suspension cultures as a function of the glucose and lactate concentration and the pH. In a second paper these models will be used to predict the moment of interaction in mixed suspension cultures and the cell concentrations at this moment. The effect of pH on the maximum specific growth rate could be described by a parabolic equation for L. curvatus and E. cloacae. E. cloacae is clearly more sensitive to a pH decrease than L. curvatus, as may be concluded from the theoretical minimum pH for growth of 5.6 for E. cloacae and 4.3 for L. curvatus. For both organisms no effect of glucose on the maximum specific growth rate could be detected and Monod kinetics with a low Monod constant was assumed. For L. curvatus the effect of lactate on the maximum specific growth rate at different initial pH values could be described by a linear relationship. For E. cloacae a slight effect of lactate on the maximum specific growth rate could only be detected at pH 7. However, this effect was negligible compared to the effect of the pH. For both organisms the lag time was modelled by the inverse of the specific growth rate. It can be concluded that, with regard to interactions between L. curvatus and E. cloacae, the pH is likely to be the most important factor in the case where L. curvatus is the dominant organism. Substrate limitation is likely to become important in the case where E. cloacae is the dominant organism or for media with a high buffer capacity.     

Storage Stability of Ground Pork Containing Meat from an Advanced Meat Recovery System

Pork trim-finely textured (PTFT), generated by advanced meat recovery which mechanically removes meat from bones under pressure, has properties that may cause shelf-life instability. Lipid oxidation, microbial growth and pH of retail displayed fresh ground pork patties were not affected (P>0.05) by addition of up to 15% PTFT. Ground pork with 15% PTFT and 3.3% sodium lactate (NaL) stored in chubs at–2.2°C for 14 days was ground and modified atmosphere packaged (MAP) or overwrapped (OW) and retail displayed for 4 days. Lipid oxidation increased (P<0.05) due to PTFT incorporation but was reduced by NaL. MAP and/or NaL reduced microbial counts and lipid oxidation. MAP maintained redness (a*) and prevented metmyoglobin formation.     

Predictive model for the combined effect of temperature,sodium lactate,and sodium diacetate on the heat resistance of Listeria monocytogenes in beef

The effects of heating temperature (60 to 73.9 degrees C), sodium lactate (NaL; 0.0 to 4.8% [wt/wt]), and/or sodium diacetate (SDA; 0.0 to 0.25% [wt/wt]) and of the interactions of these factors on the heat resistance of a five-strain mixture of Listeria monocytogenes in 75% lean ground beef were examined. Thermal death times for L. monocytogenes in filtered stomacher bags in a circulating water bath were determined. The recovery medium was tryptic soy agar supplemented with 0.6% yeast extract and 1% sodium pyruvate. Decimal reduction times (D-values) were calculated by fitting a survival model to the data with a curve-fitting program. The D-values were analyzed by second-order response surface regression for temperature, NaL level, and SDA level. The D-values observed for beef with no NaL or SDA at 60, 65, 71.1, and 73.9 degrees C were 4.67, 0.72, 0.17, and 0.04 min, respectively. The addition of 4.8% NaL to beef increased heat resistance at all temperatures, with D-values ranging from 14.3 min at 60 degrees C to 0.13 min at 73.9 degrees C. Sodium diacetate interacted with NaL, thereby reducing the protective effect of NaL and rendering L. monocytogenes in beef less resistant to heat. A mathematical model describing the combined effect of temperature, NaL level, and SDA level on the thermal inactivation of L. monocytogenes was developed. This model can predict D-values for any combination of temperature, NaL level, and SDA level that is within the range of those tested. This predictive model will have substantial practical importance to processors of cooked meat, allowing them to vary their thermal treatments of ready-to-eat meat products in a safe manner.     

EFFECTS OF pH, LACTATE CATION (K, Na, Ca), AND LACTATE ION CONCENTRATION ON IN VITRO METMYOGLOBIN-REDUCING ACTIVITY

Lactic acid salts with three different cations (K, Na, Ca) were investigated at three lactate (L) concentrations (0.1, 0.3 and 0.6 M) to evaluate in vitro metmyoglobin-reducing activity (MRA) at three pH levels (5.7, 6.4 and 7.4). All lactates generated MRA at normal meat pH (5.7), with greater MRA at pH 7.4 than at both pH 6.4 and 5.7 ( P <  0.05). No consistent differences were noted among lactates for generating MRA, except at pH 7.4 where CaL was greatest ( P <  0.05). At pH 6.4 and 7.4, MRA increased ( P <  0.05) as lactate concentration increased. This study provides evidence that lactate oxidation at postmortem muscle pH generates reducing equivalents and that addition of CaL, NaL or KL should increase MRA and color stability.

PRACTICAL APPLICATIONS

Lactate products are commonly used by the meat industry for microbial control, specifically of Listeria monocytogenes . Previous research has shown lactates to increase meat color stability as well. This research examines whether lactate products, with three different cations, can generate metmyoglobin-reducing activity (MRA) to a similar extent. Results of this study indicate that the three lactates increase MRA in vitro , even at postmortem meat pH (5.7). These data should lead to further testing of lactate products in both fresh and processed meat systems in different packaging formats, which would add additional information to meat processors' decision-making process.     

Microbiological, Sensory and Chemical Characteristics of Vacuum-Packaged Cooked Beef Top Rounds Treated with Sodium Lactate and Sodium Propionate

Cooked, vacuum-packaged beef top rounds containing 3% sodium lactate (NaL) or 3 or 4% NaL in combination with 0.1 or 0.2% sodium propionate (NaP) were stored for up to 84 days at 4°C. Addition of any of the treatments greatly reduced total Aerobic Plate Counts (APC). Positive flavor notes associated with fresh beef were enhanced by ingredient addition and tended to be highest in roasts with 3% NaL + 0.2% NaP. Cooked roast beef color was enhanced by addition of NaL alone or in combination with 0.1% NaP. Lipid oxidation and water activity were decreased by addition of NaL with NaP and pH and cooked yield were increased with any level or combination of ingredients.     

THE EFFECT OF MONO AND POLYGLYCEROL LAURATE ON SPOILAGE AND PATHOGENIC BACTERIA ASSOCIATED WITH FOODS

The antibacterial activity of monolaurin and triglycerol 1,2 laurate alone and combined with three different chelating agents, at different pH (7, 6, 5.5 and 5), different NaCl concentrations (0.5 to 7%) and various combinations of pH and NaCl concentrations was investigated. The activity of these agents against 16 bacteria (7 Gram-positive and 9 Gram-negative) was studied using the spiral gradient end point test to determine the minimum inhibitory concentration (MIC).
Monolaurin was effective against all the Gram-positive bacteria studied, but was only effective against the Gram-negative bacteria in the presence of EDTA. The inhibition was greatest at low pH and high NaCl concentrations. Concern has been expressed about the use of monolaurin in foods because of its poor solubility. Polyglycerol esters are more soluble and antimicrobial activity of these compounds has been observed. Triglycerol 1,2 laurate exerted some inhibitory effects, but was not as inhibitory as monolaurin even in the presence of the chelating agent and under conditions of low pH and high NaCl levels. Other chelators investigated (monoglyceride citrate and sodium citrate) did not promote the inhibitory effect of monolaurin.     

Influence of lactate and acetate salt adaptation on Salmonella Typhimurium acid and heat resistance

The aim of the present study was to determine the survival of Salmonella Typhimurium adapted with sodium lactate (NaL), potassium lactate/sodium acetate mixture (KL/NaA) or sodium acetate (NaA) in simulated gastric fluid (SGF) and during heat treatment. NaL-, KL/NaA- and NaA-adapted cells were prepared by incubating in tryptic soy broth (TSB) containing these salts at 5, 5 and 3% (w/v) concentration levels, respectively, for 24 h at 37 °C. The Baranyi model was used to compare the growth kinetic parameters of adapted cells. The acid and heat resistance of adapted cells were determined by incubating in SGF (pH 2.04) at 37 °C and in TSB at 55.8, 57.8 and 59.8 °C, respectively. Adapted cells had significantly (P < 0.05) longer lag phase duration (LPD) and slower maximum growth rate (MGR) than non-adapted cells. The acid resistance of KL/NaA-adapted cells was not significantly (P > 0.05) different from that of non-adapted cells. NaL-adapted cells were more susceptible to the low pH environment, whereas NaA-adapted cells showed enhanced acid resistance compared to non-adapted and other adapted cells. Unlike acid resistance, both NaL- and NaA-adapted cells showed enhanced heat resistance with increased D-values, regardless of treatment temperatures. Thus, this study indicates that adaptation of S. Typhimurium to 5% NaL or 3% NaA could enhance their ability to survive thermal processes or in the human stomach, possibly increasing the risk of Salmonella outbreaks.     

Thermal Inactivation and Postthermal Treatment Growth during Storage of Multiple Salmonella Serotypes in Ground Beef as Affected by Sodium Lactate and Oregano Oil

ABSTRACT:  We assessed the heat resistance of  Salmonella  in raw ground beef in both the absence and presence of sodium lactate, oregano oil, and in combinations of these 2 GRAS-listed ingredients, and determined their bactericidal or bacteriostatic activities during postthermal treatment storage at 15 °C. A cocktail of 8 serotypes of  Salmonella  spp. was inoculated into ground beef supplemented with sodium lactate (NaL) (1.5% and 3%) and/or oregano oil (0.5% and 1%) to obtain approximately 8 log CFU/g. The ground beef samples (3 g) were vacuum-packed and heated at 60, 65, or 71 °C in a circulating water bath for selected times to inactivate approximately 5 to 6 log CFU/g of the pathogen, and then stored at 15 °C for 15 and 30 d. Results show that especially at the lower cooking temperatures, addition of oregano oil increased the inactivation rate of  Salmonella  spp., whereas addition of NaL alone exhibited a protective effect against lethality and decreased the rate. Addition of combinations of oregano oil and NaL overcame this protective effect. During subsequent posttreatment storage for 15 d,  Salmonella  populations in the controls and in samples containing 0.5% oregano (60 and 65 °C) or 1% oregano oil (60 °C) increased to 4.5 to 6 log CFU/g. The values for all other samples were at or near undetectable levels. Results from the 30-d storage study were similar. These findings indicate that lactate and oregano oil may be used to render  Salmonella  spp. more susceptible to the lethal effect of heat and to inhibit growth of  Salmonella  spp. that survive heat treatments.     

Modeling and predicting the growth of lactic acid bacteria in lightly preserved seafood and their inhibiting effect on Listeria monocytogenes

A cardinal parameter model was developed to predict the effect of diacetate, lactate, CO2, smoke components (phenol), pH, NaCl, temperature, and the interactions between all parameters on the growth of lactic acid bacteria (LAB) in lightly preserved seafood. A product-oriented approach based on careful chemical characterization and growth of bacteria in ready-to-eat seafoods was used to develop this new LAB growth model. Initially, cardinal parameter values for the inhibiting effect of diacetate, lactate, CO2, pH, and NaCl-water activity were determined experimentally for a mixture of LAB isolates or were obtained from the literature. Next, these values and a cardinal parameter model were used to model the effect of temperature (T(min)) and smoke components (P(max)). The cardinal parameter model was fitted to data for growth of LAB (mu(max) values) in lightly preserved seafood including cold-smoked and marinated products with different concentrations of naturally occurring and added organic acids. Separate product validation studies of the LAB model resulted in average bias and accuracy factor values of 1.2 and 1.5, respectively, for growth of LAB (mu(max) values) in lightly preserved seafood. Interaction between LAB and Listeria monocytogenes was predicted by combining the developed LAB model and an existing growth and growth boundary model for the pathogen (O. Mejlholm and P. Dalgaard, J. Food Prot. 70:70-84). The performance of the existing L. monocytogenes model was improved by taking into account the effect of microbial interaction with LAB. The observed and predicted maximum population densities of L. monocytogenes in inoculated lightly preserved seafoods were 4.7 and 4.1 log CFU g(-1), respectively, whereas for naturally contaminated vacuum-packed cold-smoked salmon the corresponding values were 0.7 and 0.6 log CFU g(-1) when a relative lag time of 4.5 was used for the pathogen.     

Biopolymer-based films as carriers of antimicrobial agents

Films were prepared by incorporating different levels of antibacterial agents such as oregano oil, sodium lactate (NaL) and ɛ-polylysine (ɛ-PL) into sorbitol-plasticized whey protein isolate (WPI) films. The moisture uptake behaviour and the water vapour permeability (WVP) of the films were only affected by NaL, as the water sorption and permeability increased with addition of NaL into the protein matrix. An increase of the glass transition temperature of the sorbitol regions, as assessed by Dynamic Mechanical Thermal Analysis (DMTA), was caused by the addition of ɛ-PL, while incorporation of the oregano oil caused plasticization of the film that was depicted by a decrease in the transition temperature of the polymer-rich regions. On the other hand, incorporation of NaL into the films did not significantly alter their thermo-mechanical properties. However, the addition of NaL or ɛ-PL in the film forming solution resulted in a decline of maximum tensile strength (σ_max). Wrapping of beef cuts with the antimicrobial films resulted in a significant reduction of the bacterial population levels. The maximum specific growth rate (μ_max) of total flora (Total Viable Count, TVC) and pseudomonads was significantly reduced (P<0.05), with the use of antimicrobial films containing relatively high levels of oregano oil (1.5% w/w in the film forming solution) or ɛ-PL (0.75% w/w in the film forming solution), while the growth of Lactic Acid Bacteria (LAB) was completely inhibited.     

The growth of Aeromonas hydrophila K144 in ground pork at 5 degrees C

The influence of NaCl, pH, atmosphere, and background microflora on the growth and/or survival of Aeromonas hydrophila K144 was studied in ground pork held at 5 degrees C. In ground pork, A hydrophila was sensitive to pH values below 6.0 in the form of either a low starting pH in the pork itself or induced by lactic acid bacteria action on added glucose. Growth of the organism is inhibited by NaCl levels of 3% (w/w) (approx. 4% brine content). A hydrophila grew in vacuum-packaged ground pork; its growth was diminished by the presence of the naturally occurring meat microflora. Except for pH values below 6.0, conditions which inhibited growth permitted survival of the organisms for extended periods. Data indicate that the growth of A. hydrophila in ground pork can be controlled by factors such as NaCl, pH, and background microflora. In general, measures designed to control other foodborne pathogens appear adequate to limit A. hydrophila.     

乳酸钠对铜绿假单胞菌生长的影响

为探讨乳酸钠对铜绿假单胞菌(Pseudomonas aeruginosa)的特定抑制作用,揭示乳酸钠质量浓度与介质pH值水平影响乳酸钠抑菌效果的规律,以营养肉汤培养基为介质,按照乳酸钠质量浓度(0、0.2、0.5、1.0、1.5、2.0g/100mL)单因素试验及乳酸质量浓度与介质pH值(4.0～6.2)的两因素交互试验设计,25℃恒温培养。结果表明：在适当的pH值范围内,乳酸钠(NaL)表现出良好的抑菌效果：当介质pH值小于NaL质量浓度的抑菌临界pH值时,NaL抑菌效果与其质量浓度成正比,介质pH4.8,抑菌效果2.0g/100mL NaL＞1.0g/100mL NaL＞0.5g/100mL NaL。NaL质量浓度一定,其抑菌效果与介质pH值成反比。     

Efficacy of lactic acid salts and sodium acetate on ground beef colour stability and metmyoglobin-reducing activity

This study examined two concentrations (0.6 and 1.0mol) of three lactic acid salts (calcium lactate, CaL; potassium lactate, KL; and sodium lactate, NaL), with and without 0.01mol sodium acetate (n=3 replications), for effects on ground beef colour stability and metmyoglobin-reducing activity (MRA). Ground beef with CaL was least colour stable (P<0.05). Increasing CaL and NaL concentration decreased (P<0.05) colour stability. Ground beef with acetate only was most colour stable (P<0.05), but it did not result in more MRA (P>0.05) than control ground beef. Including both lactate and acetate was not as effective (P>0.05) in increasing colour stability as acetate alone. In general, both KL levels were equal (P>0.05) to the lower NaL concentration, and all three were superior in colour stability (P<0.05) to CaL and the higher NaL concentration. More MRA was generated by including lactates (P<0.05); KL and NaL had more MRA than CaL (P<0.05). However, these increases in MRA did not result in improved colour stability. Overall, adding KL to ground beef would not increase ground beef colour stability over adding nothing, but CaL and high levels of NaL would decrease colour stability. Using 0.01mol sodium acetate maximized ground beef colour stability.