Antimicrobial Activity and Functionality of Reduced Sodium Chloride and Potassium Sorbate in Uncured Poultry Products

Uncured turkey and chicken breast meat products, formulated with NaCl (0.65 and 1.30%) and potassium sorbate (0 and 0.26%), were tested for antimicrobial activity and functional properties. The chopped products were inoculated (Clostridium sporogenes, 10/g) in cans and in packages and abused at 20°C. Microbial growth and gas production were rapid at both NaCl levels tested. Inclusion of potassium sorbate in the formulation delayed initiation and rate of microbial growth and gas production. Potassium sorbate also reduced (P<0.05) weight losses during cooking of the low NaCl turkey product. Rates of gas production were similar in canned and vacuum packaged products. Differences in microbial growth and gas production between chicken and turkey products were minor.     

Microbial and Sensory Quality of Boneless Dry-Cured Hams as Affected by Mechanical Pressing and Potassium Sorbate

The effects of mechanical pressing and a 10% potassium sorbate dip on microbial and organoleptic properties of boneless dry-cured hams were studied. Pressing resulted in higher nitrite levels, higher cooking losses and lower Warner-Bratzler shear values (P <0.05) but did not affect (P>0.05) yields, final microbial counts or sensory characteristics. Potassium sorbate improved visual mold scores (P<0.05) and generally reduced surface aerobic yeast and mold and staphylococci counts, with several reductions being significant at the 0.01 or 0.05 levels. It also reduced saltiness and flavor intensity scores (P <0.01) but had no effect on other sensory attributes or on cooking losses.     

Study of benzoate, propionate, and sorbate salts as mould spoilage inhibitors on intermediate moisture bakery products of low pH (4.5-5.5)

A hurdle technology approach has been applied to control common mold species causing spoilage of intermediate moisture bakery products (Eurotium spp., Aspergillus spp., and Penicillium corylophilum), growing on a fermented bakery product analogue (FBPA). The factors studied included a combination of different levels of weak acid preservatives (potassium sorbate, calcium propionate, and sodium benzoate; 0-0.3%), pH (4.5-5.5), and water activity (a(w); 0.80-0.90). Potassium sorbate was found to be the most effective in preventing fungal spoilage of this kind of products at the maximum concentration tested (0.3%) regardless of a(w). The same concentration of calcium propionate and sodium benzoate was effective only at low a(w) levels. On the other hand, potassium sorbate activity was slightly reduced at pH 5.5, the 0.3% being only effective at 0.80 a(w). These findings indicate that potassium sorbate may be a suitable preserving agent to inhibit deterioration of a FBPA of slightly acidic pH (near 4.5) by xerophilic fungi. Further studies have to be done in order to adjust the minimal inhibitory concentration necessary to obtain a product with the required shelf life.     

Sensory, Physical, and Cooking Characteristics of Bacon Processed with Varying Levels of Sodium Nitrite and Potassium Sorbate

Sensory, physical, and cooking properties were evaluated on bacon processed under commercial operations in four separate plants. Three formulations with various levels of sodium nitrite and potassium sorbate were used: (1) 0 ppm sodium nitrite, (2) 40 ppm sodium nitrite 2600 ppm potassium sorbate, and (3) 120 ppm sodium nitrite. Sliced bacon was evaluated after 10, 30, 50, and 70 days of storage. “Chemical”-like flavors, prickly mouth sensations, and “sweet aromatic” aromas were found in bacon processed with 40 ppm sodium nitrite and 2600 ppm potassium sorbate. “Microbial” flavors were found in 0 ppm sodium nitrite bacon after 50 and 70 days of storage. Bacon stored for 30 days had less cooking loss and sensory panel scores indicative of more mouth coating with fat than did bacon stored for 10 days. The degree of leanness in bacon strips had more of an influence on textural, physical, and cooking characteristics than did sodium nitrite and potassium sorbate levels.     

Frankfurters with Lean Finely Textured Tissue as Affected by Ingredients

Increasing salt concentration from 1.5 to 2.5% increased the emulsion stability of frankfurters made with lean finely textured tissue (LFTT). Sodium tripolyphosphate (STPP) at 0.25% improved stability and texture as well as processing and consumer cooking yields. Kappa (K)-carra-geenan (0.5%) reduced cooking losses and increased firmness. Isolated soy protein (ISP) at 2% also improved product stability and firmness but lowered sensory scores. The effect of ISP on sensory scores was greater for those frankfurters produced from lean finely textured beef than for those with lean finely textured pork. Increasing NaCl concentration or including STPP and K-carrageenan may improve comminuted meat products which contain 50% LFTT substituted for lean meat.     

Effect of Heat Treatment and Selected Antimicrobials on the Shelf-life and Safety of Cooked, Vacuum-Packaged, Refrigerated Pork Chops

The shelf-life of refrigerated (2–4°C) pork chops inoculated with Clostridium sporogenes PA3679 and Staphylococcus aureus Z88 was examined in products sliced from loins cooked to 66°C (150°F), dipped in 5% polyphosphate blend, 2.5% potassium sorbate or 2% acetic acid solutions, vacuum-packaged and stored at 2–4°C. The effect of a second in-the-bag cooking step to 66°C (150°F) after vacuum packaging was also studied. Pork chops not reheated after packaging showed incipient spoilage after 15 days at 2–4°C, depending on surface treatment. The second cooking increased the shelf-life of refrigerated product to more than 60 days and reduced counts of inoculated cultures to undetectable levels. However, on exposure of the chops to simulated mishandling (24–25°C), clostridial growth was detected in all samples except those dipped in polyphosphate or acetic acid solutions.     

Effect of citric acid and citrate on the shelf stability of canned liver paste processed at reduced F(0) values

Citric acid and the combination of citric acid and citrate, in a few cases enriched with potassium sorbate, were tested for their stabilizing effect in a canned liver paste processed at reduced F(0) values. pH values of the rest products ranged from 5·24 to 5·76; a(w) values varied from 0·950 to 0·972. F(0) values of 0·05, 0·30 and 0·85 were applied. Before sterilization, the paste doughs were contaminated with mixtures of bacterial spores. Heated packages were challenged by incubation at 30 and 55°C for up to about 2 years. Incubated packages with the standard formulation at an F(0) of 0·05 showed the first blown cans at 30°C after 24 days. Starting from this point, at this F(0) value products with a variable, but increased, bacteriological stability were observed. At an F(0) of 0·30 a perfectly stable product at 30°C was observed after addition of 0·14% w/w citric acid only (product pH 5·69). Moreover, all tested combinations of additives at F(0) values of 0·30 and 0·85 yielded stable products at this incubation temperature. At the higher F(0) value a clear effect with respect to delaying thermophilic spoilage was observed. The effect of the application of potassium sorbate-in combination with both other additives-at F(0) values of 0·30 and 0·85 proved to be negligible.     

Influence of Sodium Tripolyphosphate on the Binding and Antimicrobial Properties of Reduced NaCl-Comminuted Meat Products

The binding and antimicrobial properties of comminuted meat products were evaluated at varying levels of NaCl and of sodium tripolyphosphate (STPP). The meat batters were inoculated with Clostridium sporogenes spores (10/g) either before (cans) or after (vacuum packages) thermal (70°C) processing. Product binding was inferior when the NaCl level was reduced to 1.1% (50% reduction). STPP increased pH by 0.17-0.23 units and restored binding of low NaCl products. During storage (20°C) microbial growth and product spoilage were more rapid with decreasing brine level, irrespective of presence or absence of STPP.     

Thermal inactivation of Escherichia coli O157:H7 in beef treated with marination and tenderization ingredients

Internalization of Escherichia coli O157:H7 in nonintact beef products during mechanical tenderization or during injection of marination and tenderization ingredients is of concern if such products are undercooked. This study tested organic acids (0.2% citric acid and 0.3% acetic acid), potassium and calcium salts (1.8% potassium lactate, 0.63% calcium lactate, 0.86% calcium ascorbate, and 0.23% calcium chloride), and sodium chloride (2.5%) for their influence on thermal destruction of E. coli O157:H7 in ground beef serving as a model system. Ground beef batches (700 g; 5% fat) were mixed with equal volumes (22 ml) of each treatment solution or distilled water and portions (30 g) of treated ground beef were extruded in test tubes (2.5 by 10 cm). A five-strain mixture of E. coli O157:H7 (0.3 ml; 7 log CFU/g) was introduced at the center of the sample with a pipette. After overnight storage (4 degrees C), simulating product marination, samples were heated to 60 or 65 degrees C internal temperature, simulating rare and medium rare doneness of beef, in a circulating water bath. At 65 degrees C, treatments with citric and acetic acid showed greater (P < 0.05) reduction (4 to 5 log CFU/g) of E. coli O157:H7 than all the other ingredients and the control (3 to 4 log CFU/g). Sodium chloride reduced weight losses (16 to 18% compared with 20 to 27% by citric or acetic acid) and resulted in a 4-log reduction in counts during cooking to 65 degrees C. Ingredients such as citric or acetic acid may improve thermal inactivation of E. coli O157:H7 internalized in nonintact beef products, while sodium chloride may reduce cooking losses in such products.     

Calcium Chloride and Potassium Sorbate Reduce Sodium Chloride used during Natural Cucumber Fermentation and Storage

Cucumber fermentation characteristics and pickle quality were evaluated in brines containing equilibrium concentrations of 0-0.4% CaCl₂, 0-0.4% potassium sorbate and 0-10% NaCl. Changes in brine pH and acidity, cucumber texture and color, coliforms, lactic acid and total bacteria, yeasts and molds were followed over time. Results indicated that cucumber spoilage would eventually take place if NaCl or potassium sorbate were not present in the brine. The presence of CaCl₂ helped maintain cucumber firmness. A synergistic action between NaCl, CaCl₂ and potassium sorbate was seen, which allowed good quality pickles to be produced when moderate amounts of all three components were present in the brine (5% NaCl, 0.2% CaCl₂, 0.2% potassium sorbate).     

Aspergillus Flavus, Aspergillus Niger, and Penicillium Corylophilum Spoilage Prevention of Bakery Products by Means of Weak-Acid Preservatives

ABSTRACT: Apart from Eurotium species, Aspergillus and Penicillium isolates are common contaminants of bakery products. This paper deals with the use of weak-acid preservatives (potassium sorbate, calcium propionate, and sodium benzoate) to prevent spoilage by Aspergillus niger, A. flavus , and Penicillium corylophilum in analogs of a bakery product. A hurdle technology approach has been considered in which factors other than preservatives are pH and water activity. Potassium sorbate has been found to be the most effective in preventing fungal spoilage of this kind of products at the maximum concentration tested (0.3%). Suboptimal doses (0.03%) of all preservatives tested led to an enhancement of growth of Aspergillus and Penicillium isolates. The characteristics of the products involved must be carefully considered before making the decision of adding weak-acid preservatives; moreover, they must be added at the right concentrations. Furthermore, more research is needed on the use of alternative natural preservatives, such as essential oils.     

Effects of Potassium Sorbate Alone and in Combination with Sodium Chloride on the Growth of Salmonella typhimurium 7136

The effects of potassium sorbate alone and in combination with 2 or 3% sodium chloride (NaCl) on the growth of Salmonella typhimurium ATCC 7136 were examined. Growth studies were performed in tryptic soy brogh (adjusted to a final pH 6.3) at 22°C for 15 days and 35°C for 48 hr without shaking. A dual plating procedure was employed to monitor growth (tryptic soy agar) and development of injury in the cell population (Levine's eosine methylene blue agar + 2% NaCl + 0.05% sodium desoxycholate). The difference between these two plate counts served as a measure of the number of injured organisms. It was found that combinations of sorbate and NaCl were more effective in the inhibition of S. typhimurium than sorbate alone under the conditions and variables studied. No injury was observed in the cell population as determined by our assay procedure. The combination of 3% NaCl + 0.3% potassium sorbate was the most effective in inhibiting growth of S. typhimurium at either storage temperature.     

Inhibitory effect of organic acid salts on spoilage flora in culture medium and cured cooked meat products under commercial manufacturing conditions

Lactobacillus curvatus, isolated from a spoiled vacuum-packaged 'pariza' type meat product, was used to inoculate modified MRS broth containing sodium lactate, sodium acetate and potassium sorbate in different concentrations, alone or in inter se combinations. Two commercial preparations (MIX 1 and MIX 2) were also used containing combinations of the above antimicrobials. Results from the preservatives addition to the culture medium showed highest antimicrobial activity in the case of the sodium lactate (2%, 3% or 4%), sodium acetate (0.5%) and potassium sorbate (0.15%) combination. Results from the preservatives addition to two types of thermally processed meats showed that sodium lactate and the combination of sodium lactate, sodium acetate and potassium sorbate were the most effective; extending the products shelf life an additional 10 days. Finally, MIX 1 and MIX 2 suppressed the lactic acid bacteria (LAB) growth in the culture medium but not in the final product.     

Factors controlling the growth of Clostridium botulinum types A and B in pasteurized, cured meats III. The effect of potassium sorbate

The growth of Clostridium botulinum types A and B spores, at 10¹ or 10³ per container, was studied in a pork slurry system containing nitrite (40 μg/g), sodium chloride (2.5, 3.5, 4.5% w/v) sodium isoascorbate (550 μg/g) at varying pH levels, with or without potassium sorbate (0.26% w/v), without heating and after two heat treatments (80°C for 7 min, and 80°C for 7 min + 70°C for 1 hr) followed by storage at 15, 17.5, 20 or 35°C for up to 6 months. At a given spore inoculum, potassium sorbate significantly decreased toxin production, as did increasing NaCl, decreasing pH or decreasing storage temperature. Heat treatment did not significantly affect spoilage or toxin production overall, but interacted significantly with some factors. The effect of sorbate was greater at 3.5% NaCl than at 2.5%, at pH values below 6.0, and at low storage temperature.     

Efficacy of sorbates on the control of the growth of Eurotium species in bakery products with near neutral pH

The effects of sorbic acid and potassium sorbate on growth of different Eurotium isolates when added to a bakery product analogue were tested under different environmental conditions. Water activity of the products was adjusted to values in the range of 0.75-0.90, and storage temperatures were in the range of 15-30 degrees C. Preservatives were added in concentrations ranging from 0.025% to 0.2%. It was observed that 0.025% and 0.05% concentrations always enhanced the isolates growth, while 0.1% had little preservative effect. Finally, even the highest concentration (0.2%) was not suitable as it only controlled fungal growth under certain water activity and temperature levels. It was concluded that these weak-acid preservatives are not useful when added to bakery products with near to neutral pH.     

Multiresponse Optimization Minimizes Salt in Natural Cucumber Fermentation and Storage

Response surface methodology was used during natural cucumber fermentation and storage to quantitatively determine effects of NaCl (0–10%), CaCl₂ (0–0.4%) and potassium sorbate (0–0.4%) on brine pH, cucumber texture and microbial (yeast/mold) contamination. Multiresponse optimization methods (conventional and improved graphical methods, extended response surface procedure and desirability function approach) were employed to minimize use of NaCl. Cucumbers fermented and stored in brines containing ～3% NaCl, 0.28% CaCl, and 0.3% potassium sorbate were predicted to exhibit vigorous fermentation, be free of yeast/mold contamination, and maintain good firmness after 6 mo storage. Predicted results were experimentally confirmed.     

The effect of cooking on the chemical composition of meat products with special reference to fat loss

The chemical composition and energy content of four product categories (sausages, restructured steaks, burgers and minced beef) were determined before and after cooking. Two cooking methods were used for each product category: sausages and burgers were fried or grilled, restructured steaks were grilled or cooked in an oven whilst mince was either boiled or lightly fried and then boiled to simulate domestic practice. Based on an initial 100 g of product and excluding the low fat products included in the survey, the average weights after cooking were 78, 73, 72 and 70 g for the sausages, restructured steaks, burgers and minced beef, respectively; average fat contents before and after cooking were 22 and 17 g for the sausages, 17 and 14 g for the restructured steaks, 25 and 16 g for the beef burgers, and 19 and 7 g for the mince; and average energy contents before and after cooking were 1215 and 1016 kJ for the sausages, 958 and 815 kJ for the restructured steaks, 1244 and 906 kJ for the burgers and 1009 and 544 kJ for the mince. For a given product type, cooking method was relatively unimportant; the cooking loss, fat loss and energy content of the cooked product being more dependent on product formulation and manufacturing process. The survey included a low fat sausage, a low fat burger, a lean mince and an extra lean mince with fat contents of 8.7, 7.5, 12.4 and 5.2%, respectively. Overall weight losses during cooking were similar to standard products, though low fat products lost proportionally more water and less fat. Frying resulted in a slight gain in fat content for the low fat sausages and burgers, based on an initial 100 g of product, though fried low fat products still had lower fat and energy contents than standard products. It is argued that national consumption figures should take into account the losses that occur during cooking to avoid overestimating fat and energy intake levels.     

干酪成熟初期产生生物胺影响因素的研究

研究了成熟3个星期的干酪产生生物胺的4种影响因素（发酵剂，NaCl，山梨酸钾，水分质量分数），通过氨基酸专用高效液相色谱仪对样品进行了测定。结果表明，发酵剂RA024，NaCl质量分数高，山梨酸钾质量分数在0．2％，水分质量分数低可以抑制生物胺的产生。     

Evaluation of Brining Ingredients and Antimicrobials for Effects on Thermal Destruction of Escherichia coli O157:H7 in a Meat Model System

ABSTRACT: Escherichia coli O157:H7 may become internalized during brine injection of meat. This study evaluated the effect of brining ingredients on E. coli O157:H7 in a meat model system after simulated brining, storage, and cooking. Fresh knuckles (5.3 ± 2.4% fat) or beef shoulder (15.3 ± 2.2% fat) were ground individually, mixed with an 8-strain composite of rifampicin-resistant E. coli O157:H7 (7 log CFU/g) and brining solutions. Treatments included no brining, distilled water, sodium chloride (NaCl, 0.5%), sodium tripolyphosphate (STP, 0.25%), sodium pyrophosphate (SPP, 0.25%), NaCl + STP, NaCl + SPP, NaCl + STP + potassium lactate (PL, 2%), NaCl + STP + sodium diacetate (SD, 0.15%), NaCl + STP + PL + SD, NaCl + STP + lactic acid (0.3%), NaCl + STP + acetic acid (0.3%), NaCl + STP + citric acid (0.3%), NaCl + STP + EDTA (20 mM) + nisin (0.0015%) or pediocin (1000 AU/g), NaCl + STP + sodium metasilicate (0.2%), NaCl + STP + cetylpyridinium chloride (CPC; 0.5%), and NaCl + STP + hops beta acids (0.00055%). Samples (30 g) were analyzed for pH, and total microbial and rifampicin-resistant E. coli O157:H7 (inoculum) populations immediately after mixing, storage (24 h at 4 °C), and cooking to 65 °C. Fat and moisture contents and water activity were measured after storage and cooking only; cooking losses also were determined. The effect of beef type on microbial counts, pH, and water activity was negligible. No reductions in microbial counts were obtained by the brining solutions immediately or after storage, except for samples treated with CPC, which reduced (P < 0.05) pathogen counts after storage by approximately 1 log cycle. Cooking reduced pathogen counts by 1.5 to 2.5 logs, while CPC-treated samples had the lowest (P < 0.05) counts compared to any other treatment. These data may be useful in developing/improving brining recipes for control of E. coli O157:H7 in moisture-enhanced beef products.