Effects of lactic and acetic acid salts on quality characteristics of enhanced pork during retail display

The objective of this study was to evaluate the sensory and physical characteristics of pork chops from loins enhanced to 110% of original weight with either (1) potassium lactate, potassium diacetate, phosphate and salt, (2) sodium lactate, phosphate and salt, (3) potassium lactate, phosphate and salt, (4) sodium acetate, phosphate and salt, or (5) phosphate and salt. A trained sensory panel evaluated pork flavor, saltiness, bitterness, soapy flavor, acid flavor, juiciness and tenderness of cooked chops. Visual color of raw chops was also evaluated. After 96 h in display, chops enhanced with lactate/diacetate had significantly lower (P<0.01) aerobic plate counts than control (unpumped) chops, or those pumped with other solutions. Lactate/diacetate-enhanced chops maintained higher a* and b* values during display, and had less visual discoloration after 96 h display. Chops pumped with lactate, acetate or the lactate/diacetate mixture were more tender and juicy, and had more pork flavor than controls or those pumped with phosphate/salt only. There appears to be a significant advantage to using a lactate/diacetate enhancement solution over either lactate or acetate alone.     

Psychrotrophic clostridia causing spoilage in cooked meat and poultry products.

Certain types of commercially produced noncured turkey breast and roast beef are precooked in situ, stored at 4 degrees C or below, and typically given use by dates of greater than 50 days. While of rare, sporadic occurrence, an unpleasant spoilage characterized by strong H2S odor and gas production has been observed in these products. This spoilage is due to the growth of psychrotrophic anaerobic sporeformers. Isolates from roast beef resemble Clostridium laramie while isolates from uncured turkey have been designated C. ctm for cooked turkey meat. The turkey breast isolates were characterized by temperature growth ranges, carbohydrate fermentations, and other biochemical reactions. Growth of all isolates was inhibited in broth media by 3.0% NaCl, 100 ppm nitrite, 2.0% sodium lactate, or 0.2% sodium diacetate. Inoculated studies were performed with three isolates in cooked turkey product. All three isolates grew and spoiled product at 10 and 3.3 degrees C, and one isolate grew at 0.5 and -3 degrees C. Some differences in growth were observed with the lactate and diacetate treatments in turkey meat among the three isolates. One isolate appeared to utilize the lactate, two were inhibited. Overall, 0.1% diacetate consistently delayed growth, although to different degrees, for all isolates.     

Effects of Shelf-Life Enhancers on E. coli K12 Survival in Solutions Used to Enhance Beef Strip Steaks

ABSTRACT:  The objective of this study was to evaluate the effects of enhancement solutions containing sodium lactate or sodium lactate/sodium diacetate on E. coli K12 transmission to beef strip steaks and in purge. Solutions containing salt, phosphate, and shelf-life enhancers were injected to 10% over initial weight of the steaks. Lactate or lactate/diacetate addition to a solution inoculated with 6 log₁₀ E. coli K12 CFU/mL was equally effective in limiting growth resulting in a 1-2 log₁₀ CFU/g reduction when compared to salt/phosphate in steaks. When inoculation level was 3 log₁₀ CFU/mL in the enhancement solution, microbial growth was detectable only in the purge of steaks enhanced with salt/phosphate only. Lactate increased CIE L* value and b* and decreased a* values when compared to the control. Lactate-/diacetate-containing solutions decreased L* values when compared to lactate alone. Lactate/diacetate also reduced purge loss from steaks compared to lactate and salt/phosphate solutions.     

Storage stability of low-fat sodium reduced fresh merguez sausage prepared with olive oil in konjac gel matrix

This paper evaluates the nutritional values and stability during refrigerated storage of fresh beef merguez sausage as affected by a reformulation process which modified the fat content both by reducing fat (replacing beef fat with konjac gel) and incorporating olive oil (replacing beef fat with olive oil stabilized in a konjac matrix) and by reducing sodium content, replacing sodium chloride with a salt mixture (containing potassium chloride, calcium chloride and magnesium chloride). A preservative (sodium metabisulphite) was also used to extend the shelf-life of the product. The fat was reduced by 32 to 80% and sodium by over 36%. The reformulation did not negatively affect the sensory evaluation. Low microbiota growth rate and biogenic amines were attributed mainly to the presence of sodium metabisulphite. This preservative could be used in the reformulation to enhance safety and/or extend the shelf-life of this type of product.     

Enhanced antimicrobial effects of combination of lactate and diacetate on Listeria monocytogenes and Salmonella spp. in beef bologna

The antimicrobial activities of salts of organic acids such as lactate and acetate are well documented, but there is limited information on their effect when used in combination. We previously reported enhanced inhibition of Listeria monocvtogenes and Salmonella enterica serovar Enteritidis in sterile comminuted beef at 5 and 10 degrees C by combinations of sodium lactate (SL) (2.5%) and sodium diacetate (SDA) (0.2%). The present study was undertaken to evaluate the inhibitory effect of these salts, alone and in combination, in ready-to-eat (RTE) meat. Single strains and six-strain mixtures of each of the pathogens ( approximately 3 log CFU/g) were tested in beef bologna during aerobic storage at 5 and 10 degrees C for up to 60 days. The growth rate of the six-strain mixture of Listeria was faster than that of the single strain (Scott A) in the lactate/diacetate-free product. While each of the salts delayed growth of the listeriae at 5 degrees C, the effect of their combination was listericidal for the single strain and listeriostatic for the six-strain mixture. Enhanced inhibition by the salt combination was also observed at 10 degrees C. Salmonella numbers declined to undetectable levels in the untreated meat product and in each of the treatments after 20-30 days. However, the decline was more rapid in meat with the combination of the salts during storage at both 5 and 10 degrees C. Each of the salts further delayed the growth of the background microflora during storage at 5 degrees C, with their combinations showing the most effect.     

Effects of brine ingredients and temperature on cook yields and tenderness of pre-rigor processed roast beef

In semimembranosus (SM) muscles removed pre- and post-rigor and injected 10% (wt/wt) with brines formulated to give 2% salt, 1.5% glucose, 0.3% phosphate, 0.15% calcium chloride or 3% sodium lactate in the finished product and cooked within 1 h of injection, cook yields were not significantly affected by processing pre- or post-rigor. Within treatments, however, brine composition had a significant (P < 0.05) effect on cook yields; highest yields were obtained using salt (although this was not significantly different from the water injected control) and lowest yields with calcium chloride. Adding phosphate resulted in lower peak shear force values, and less energy was required to break the sample. The most tender roasts from pre-rigor meat were produced using salt, phosphate or lactate brines and the least tender using calcium chloride. Brine temperature (0-12 °C) during injection had little effect on cook yields or tenderness of the roast beef manufactured pre-rigor. The results indicate that accelerated processing of roast beef can result in finished product with acceptable yields and tenderness if salt and phosphate brines are used.     

Shelf-life of Algin/Calcium Restructured Turkey Products Held under Aerobic and Anaerobic Conditions

The shelf-life of restructured products made with ground turkey or turkey breast pieces and formulated with combinations of 0.5–1.0% sodium alginate, 0.1–0.2% calcium carbonate and 0.15–0.30% lactate (ACL) was compared to product containing a combination of 1.4% NaCl and 0.32% sodium tripolyphosphate and to no-additive controls stored at 4°C under aerobic and anaerobic conditions. No significant (p > 0.05) differences were observed between ACL and salt/phosphate restructured turkey products in the rate and extent of growth of psychrotrophs or lactic acid bacteria. The salt/phosphate combination, however, repressed (p<0.05) the growth of pseudomonads. Overall, inclusion of ACL did not influence spoilage of restructured turkey meat products held under aerobic or anaerobic conditions.     

Irradiation of pre-packaged sliced cooked meat products with low and normal sodium content

Irradiation experiments were carried out with pre-packaged sliced cooked meat products with different initial counts of Enterobacteriaceae and mesophilic aerobic bacteria. In low-sodium meat products Enterobacteriaceae could effectively be inactivated in refrigerated or frozen products by irradiation with a dose of 1 or 2 kGy respectively, provided the number of these bacteria was below 10(3) to 10(4) per g. The low-sodium meat products involved endured above treatment without being seriously affected as to sensory qualities. Shelf-life of salted cooked meat products could be prolonged by irradiating the frozen product. Irradiation with a dose of 2 kGy enabled uncooled storage of the product for a restricted period (5-7 days). Best results were obtained for meat products with a salt content in the brine phase of greater than 4.0% (w/w) and having a good hygienic quality, i.e. an initial bacterial count below 10(4)/g. Packaging in a gas atmosphere (CO2) slightly enhanced protection as compared to vacuum packaging. Off-flavours as a result of irradiation of salted cooked meat products varied from slight to strong and depended on the type of product.     

豇豆乳酸发酵工艺控制及酸豇豆炒肉末保质初探

豇豆乳酸发酵过程中,以0.5‰双乙酸钠作防腐剂,用米醋调节pH值至4.0～4.5,补充1%冰糖,食盐浓度控制5%对促进乳酸菌迅速形成优势菌群抑制杂菌有利,同时添加0.2%CaCl2可延缓组织软化;对酸豇豆炒肉末商品化生产,酸豇豆先干炒脱水、0.05%山梨酸钾与0.05%苯甲酸钠混合防腐、铝膜复合袋包装、85℃水浴30min间隔24h。两次杀菌可尽量延长产品货架期,确保产品脆度、色泽和风味。     

Combining reformulation,active packaging and non-thermal post-packaging decontamination technologies to increase the microbiological quality and safety of cooked ready-to-eat meat products

BackgroundCooked ready-to-eat (RTE) meat products are subjected to contamination of spoilage microorganisms such as lactic acid bacteria and pathogens such as Listeria monocytogenes. These microorganisms contaminate cooked RTE meat products after the cooking step and may further grow during shelf-life potentially leading to spoilage or foodborne diseases, respectively. In the current context of salt, fat and chemical preservatives reduction in meat products formulations, a combined strategy that considers the development of more robust formulations, active packaging and the use of non-thermal post-packaging decontamination strategies seems required to ensure shelf-stable and safe RTE cooked food products.Scope and approachThe main objective of this review was to discuss the aspects related to reformulation, active packaging and the application of non-thermal decontamination technologies at the post-packaging step of cooked RTE meat products, their advantages, limitations and main challenges for their implementation.Key findings and conclusionsIn general, post-packaging decontamination technologies aim to reduce or inactivate pathogens and spoilage microorganisms present on the surface of ready-to-eat meat products. Low-temperature plasma, high-pressure processing (HPP), pulsed electric fields, pulsed ultraviolet light and ultrasound are promising alternatives in this segment. However, the choice of the most appropriate approach for post-packaging decontamination of cooked ready-to-eat meat products depends on the type of product and the technological objectives. Meat products formulation and packaging material properties should be considered while defining a post-packaging decontamination approach. Although they are advantageous, non-thermal technologies may present certain limitations such as the increase of oxidative reactions over the shelf-life.     

Control of Listeria monocytogenes in ready-to-eat meats containing sodium levulinate, sodium lactate, or a combination of sodium lactate and sodium diacetate

ABSTRACT:  This study investigated the use of sodium levulinate to prevent outgrowth of Listeria monocytogenes in refrigerated ready-to-eat (RTE) meat products. Turkey breast roll and bologna were formulated to contain 1%, 2%, or 3% (w/w) sodium levulinate, 2% sodium lactate, a 2% combination of sodium lactate and sodium diacetate (1.875% sodium lactate and 0.125% sodium diacetate), or no antimicrobial (control). Samples of the RTE products were sliced, inoculated with 10² to 10³ CFU/cm² of a 5-strain cocktail of L. monocytogenes , vacuum packaged, and stored at refrigeration temperature for 0 to 12 wk. Counts reached 10⁸ CFU/cm² on control turkey roll product after 8 wk, and over 10⁷ CFU/cm² on control bologna after 12 wk. Addition of 2% or more sodium levulinate to turkey roll and 1% or more sodium levulinate to bologna completely prevented growth of L. monocytogenes during 12 wk of refrigerated storage. A consumer taste panel with pathogen-free samples found no differences in the overall liking among the preparations of turkey roll or among preparations of bologna. These results show that sodium levulinate is at least as effective at inhibiting outgrowth of L. monocytogenes in RTE meat products as the current industry standards of lactate or lactate and diacetate, and levulinate addition does not alter the overall liking of the RTE meat products.     

Inhibitory effects of organic acid salts on growth of Clostridium perfringens from spore inocula during chilling of marinated ground turkey breast

Inhibition of Clostridium perfringens germination and outgrowth by salts of organic acids such as sodium lactate, sodium acetate, buffered sodium citrate and buffered sodium citrate supplemented with sodium diacetate was evaluated during continuous chilling of ground turkey. Turkey breast meat was injected with a brine-containing NaCl, potato starch and potassium tetra pyrophosphate to yield final in-product concentrations of 0.85%, 0.25% and 0.20%, respectively. The meat was ground, mixed with either sodium lactate (1%, 2%, 3% or 4%), sodium acetate (1% or 2%), buffered sodium citrate (Ional, 1%) or buffered sodium citrate supplemented with sodium diacetate (Ional Plus trade mark, 1%), in addition to a control that did not contain added antimicrobials. Each product was mixed with a three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.8 log10 spores/g. Inoculated products (10 g) were packaged into cook-in-bags (2 x 3 in.), vacuum sealed, cooked at 60 degrees C for 1 h, and subsequently chilled from 54.4 to 7.2 degrees C in 15, 18 and 21 h following exponential chilling rates. Products were sampled immediately after cooking and then after chilling. Chilling of cooked turkey following 15, 18 and 21 h chill rates resulted in germination and outgrowth of C. perfringens spores to 6.6, 7.58 and 7.95 log10 CFU/g populations, respectively, from initial spore populations of ca. 2.80 log10 CFU/g. Incorporation of sodium lactate (1%), sodium acetate (1%), Ional or Ional Plus (1%) substantially inhibited germination and outgrowth of C. perfringens spores compared to controls. Final C. perfringens total populations of 3.12, 3.10, 2.38 and 2.92 log10 CFU/g, respectively, were observed following a 15-h exponential chill rate. Similar inhibitory effects were observed for 18 and 21 chill rates with the antimicrobials at 1% concentrations. While sodium lactate and sodium acetate concentrations of 1% were sufficient to control C. perfringens germination and outgrowth (<1.0 log10 CFU/g growth) following 15 h chill rates, higher concentrations were required for 18 and 21 h chill rates. Ional at 1% concentration was effective in inhibiting germination and outgrowth to <1.0 log10 CFU/g of C. perfringens for all three chill rates (15, 18 and 21 h) tested. Use of sodium salts of organic acids in formulation of ready-to-eat meat products can reduce the risk of C. perfringens spore germination and outgrowth during chilling.     

Low-fat meat products-technological problems with processing

Diet and health advice serve as a driving force to redirect the types of foods considered to be most beneficial in terms of improved health and quality of life for Americans. Although meat cuts have become leaner, products such as ground beef, fresh pork sausage, coarse ground sausages and emulsified sausages traditionally have higher levels of fat. However, these products offer the greatest opportunity for fat reduction by reformulation with fat substitutes. Fat replacements should contribute a minimum of calories to a product and should not be detrimental to organoleptic qualities. Most substitutes can be categorized as: leaner meats, added water, protein-based substitutes, carbohydrate-based substitutes and synthetic compounds, Reducing the fat content to ～10% often results in cooked ground beef that is bland and dry with a hard, rubbery or mealy texture. Reformulation with fat substitutes can cause a reduction in particle binding, darker product color, lack of beef flavor, reduced browning reactions and shorter microbiological shelf-life. Other problems that occur with low-fat (5-10%) fresh or cooked/smoked sausages are reduced cook yields, soft mushy interiors, rubbery skin formation, excessive purge in vacuum packages, shorter shelf-life and changes in sensory qualities after cooking or reheating. However, some combinations of fat replacements that mimic the mouthfeel and textural characteristics of fat offer potential for development of low-fat meat products.     

Use of organic acids for the control of Clostridium perfringens in cooked vacuum-packaged restructured roast beef during an alternative cooling procedure

This study was conducted to determine how well Clostridium perfringens spores germinate and grow in restructured roast beef treated with different commercial organic salts during an alternative chilling procedure. The meat was prepared according to an industrial recipe (10% water, 1.5% sodium chloride, and 0.5% sodium triphosphate). The base meat was treated with sodium citrate at 2 or 4.8% (wt/wt), buffered to a pH of 5.6, 5.0, or 4.4 (six treatments); a 60% (wt/wt) solution of sodium lactate at 2 or 4.8% (wt/wt); sodium acetate at 0.25% (wt/wt); or sodium diacetate at 0.25% (wt/wt). Untreated meat was used as a control. Meat samples were inoculated with a three-strain cocktail of C. perfringens spores (strains ATCC 10388, NCTC 8238, and NCTC 8239). Meat was vacuum packaged in bags and cooked in a stirred water bath to an internal temperature of 75 degrees C for 20 min, and then the bags were cooled from 54.4 to 4.4 degrees C within 18 h. Samples were taken after inoculation, after cooking, and after chilling. Spore and vegetative cell counts were obtained after incubation at 37 degrees C for 8 to 10 h in Fung's Double Tubes containing tryptose sulfite agar without egg yolk enrichment. Cooking was not sufficient to eliminate C. perfringens spores. Over the 18-h cooling period, sodium citrate, sodium lactate, and sodium diacetate reduced the growth of C. perfringens to < 1 log unit, a growth level that meets U.S. Department of Agriculture performance standards. The use of sodium citrate or sodium lactate at a concentration of > or = 2% (wt/wt) inhibited C. perfringens growth over the 18-h cooling period.     

Co-culture experiments demonstrate the usefulness of Lactobacillus sakei 10A to prolong the shelf-life of a model cooked ham

This study investigated the usefulness of two selected lactic acid bacteria, Lactobacillus sakei subsp. carnosus (10A) and the lactocin S producing L. sakei 148 (LS5), to extend the shelf-life of cooked meat products. The interaction between these potential protective cultures and the spoilage organisms, Leuconostoc mesenteroides (LM4) and Brochothrix thermosphacta (BT1), were examined in co-culture studies on a model cooked ham product at 7 degrees C under vacuum packaged conditions. Furthermore, the influence of the glucose content of the model cooked ham on the interaction phenomena was investigated. When artificially contaminating the model cooked ham with BT1 at 10(2) cfu/g in combination with 10A at 10(5) cfu/g, the growth of BT1 was significantly slower compared to a simultaneous mono-culture experiment. In a similar experiment with LM4, LM4 reached a level of 10(7) cfu/g +/-14 days later when LM4 grew together with 10A compared to its growth in mono-culture. The lactocin S producing LS5 did not demonstrate an inhibitory action towards LM4 or BT1 and is therefore not useful as protective culture on cooked meat products. The glucose level of the model cooked ham had no influence on the observed antagonistic interactions of 10A towards LM4 or BT1, indicating that the action of the biopreservative 10A in cooked meat products is independent of the substrate glucose.     

Effects of salt and some antioxidants upon the TBA numbers of meat

The effects of salt alone (2%) or coated with α-tocopherol or with Tenox 4 (BHA-citric acid-propylene glycol) or in a mixture containing BHA and BHT with salt on the TBA numbers of raw and cooked beef were determined after holding for 0 or 2 days at 4°C. Salt accelerated lipid oxidation both during cooking and subsequent storage. The α-tocopherol-coated salt also increased lipid oxidation, but only during storage after cooking. Both Tenox 4-coated salt and the mixture of BHA and BHT with salt completely inhibited lipid oxidation in cooked meat, both during cooking and upon subsequent storage. Results suggest that selected antioxidants can be used to inhibit the development of warmed-over flavor (WOF) in cooked meats.     

Design of a new cooked meat sausage enriched with calcium

The effect of calcium lactate, calcium gluconate and calcium citrate addition on the sensory properties of cooked meat sausages has been studied. Conventional and reduced-fat products (approx. 40%) were manufactured. The calcium salts studied were added in sufficient amounts to 100g of final product to give 20% and 25% of calcium RDA (1200mg). The energy value reduction in the final products was close to 30%. The instrumental measurement of colour and texture was performed. The presence of calcium salts only slightly decrease the lightness of the sausage and few changes were observed in relation to the texture. These were mainly related to increased hardness, observed at levels of calcium at 25% RDA. Sensory properties were estimated by a hedonic test. In general terms, they were very acceptable, which indicated that it is possible to manufacture conventional and reduced-fat cooked meat products enriched with calcium as a new healthier meat product.     

Antimicrobials in the formulation to control Listeria monocytogenes postprocessing contamination on frankfurters stored at 4 degrees C in vacuum packages.

Postprocessing contamination of cured meat products with Listeria monocytogenes during slicing and packaging is difficult to avoid, and thus, hurdles are needed to control growth of the pathogen during product storage. This study evaluated the influence of antimicrobials, included in frankfurter formulations, on L. monocytogenes populations during refrigerated (4 degrees C) storage of product inoculated (10(3) to 10(4) CFU/cm2) after peeling of casings and before vacuum packaging. Frankfurters were prepared to contain (wt/wt) sodium lactate (3 or 6%, as pure substance of a liquid, 60% wt/wt, commercial product), sodium acetate (0.25 or 0.5%), or sodium diacetate (0.25 or 0.5%). L. monocytogenes populations (PALCAM agar and Trypticase soy agar plus 0.6% yeast extract [TSAYE]) exceeded 10(6) CFU/cm2 in inoculated controls at 20 days of storage. Sodium lactate at 6% and sodium diacetate at 0.5% were bacteriostatic, or even bactericidal, throughout storage (120 days). At 3%, sodium lactate prevented pathogen growth for at least 70 days, while, in decreasing order of effectiveness, sodium diacetate at 0.25% and sodium acetate at 0.5 and 0.25% inhibited growth for 20 to 50 days. Antimicrobials had no effect on product pH, except for sodium diacetate at 0.5%, which reduced the initial pH by approximately 0.4 U. These results indicate that concentrations of sodium acetate currently permitted by the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) (0.25%) or higher (0.5%) may control growth of L. monocytogenes for approximately 30 days, while currently permitted levels of sodium lactate (3%) and sodium diacetate (0.25%) may be inhibitory for 70 and 35 to 50 days, respectively. Moreover, levels of sodium lactate (6%) or sodium diacetate (0.5%) higher than those presently permitted by the USDA-FSIS may provide complete control at 4 degrees C of growth (120 days) of L. monocytogenes introduced on the surface of frankfurters during product packaging.     

Modeling the lag phase and growth rate of Listeria monocytogenes in ground ham containing sodium lactate and sodium diacetate at various storage temperatures

ABSTRACT:  Refrigerated ready-to-eat (RTE) meats contaminated with Listeria monocytogenes were implicated in several listeriosis outbreaks. Lactate and diacetate have been shown to control L. monocytogenes in RTE meats. The objective of this study was to examine and model the effect of lactate (1.0% to 4.2%) and diacetate (0.05% to 0.2%) in ground ham on the lag phase duration (LPD, h) and growth rate (GR, log CFU/h) of L. monocytogenes at a range of temperatures (0 to 45 °C). A 6-strain mixture of L. monocytogenes was inoculated into ground ham containing lactate and diacetate, and stored at various temperatures. The LPD and GR of L. monocytogenes in ham as affected by lactate, diacetate, and storage temperature were analyzed and accurately represented with mathematical equations. Resulting LPD and GR equations for storage temperatures within the range of 0 to 36 °C significantly represented the experimental data with a regression coefficient of 0.97 and 0.96, respectively. Significant factors ( P < 0.05) that affected the LPD were temperature, lactate, diacetate, and the interactions of all three, whereas only temperature and the interactions between temperature and lactate and diacetate had a significant effect on GR. At suboptimal growth temperatures (≤12 °C) the increase of lactate and diacetate concentrations, individually or in combination, extended the LPD. The effect of higher concentrations of both additives on reducing the GR was observed only at temperatures that were more suitable for growth of L. monocytogenes , that is, 15 to 35 °C. These data may be used to assist in determining concentrations of lactate and diacetate in cooked ham products to control the growth of L. monocytogenes over a wide range of temperatures during manufacturing, distribution, and storage.