Inhibition of Salmonella by Sodium Nitrite and Potassium Sorbate in Frankfurters

All beef frankfurters and beef-pork frankfurters containing various levels of sodium nitrite (0, 50, or 156 ppm) or potassium sorbate (0, 0.26, or 0.39%) alone or in combination (50 ppm nitrite + 0.26% sorbate) were prepared. Frankfurters were inoculated with nalidixic acid resistant Salmonella and incubated at 15°C and 27°C for up to 21 days. Frankfurters formulated with 50 or 156 ppm nitrite and incubated at 27°C, or 50 ppm nitrite and incubated at 15°C failed to inhibit the growth of Salmonella. Sorbate alone and sorbate in combination with 50 ppm nitrite were equally effective in inhibiting Salmonella at either temperature and were equivalent to 156 ppm nitrite in inhibiting Salmonella at 15°C.     

Effect of Sodium Acid Pyrophosphate in Combination with Sodium Nitrite or Sodium Nitrite/Potassium Sorbate on Clostridium botulinum Growth and Toxin Production in Beef/Pork Frankfurter Emulsions

Combinations of sodium acid pyrophosphate (SAPP) with added sodium nitrite and/or potassium sorbate were tested at various pH levels to determine effectiveness in delaying Clostridium botulinum growth and toxin production in frankfurter emulsions. Formulations containing sodium nitrite (40 ppm), potassium sorbate (0.26%) and SAPP (0.4%) resulted in a greater delay of toxin production (12–18 days) than other combinations (6–12 days) having similar pH values. Treatments containing 0.4% SAPP appeared to be more inhibitory than their counterparts without SAPP, displaying less numbers of toxic samples during the 53-day storage period at 27°C. Aerobic mesophilic colony counts and residual nitrite data showed little difference among treatments.     

Effect of Packaging Film and Vacuum Level on Regular and Sorbate-Cured Bacon

Bacon was produced with either 40 ppm NaNO₂/0.26% potassium sorbate, or 120 ppm NaNO₂. Slices were packaged in either nylon/Surlyn or nylon/Saran/Surlyn pouches and sealed at either a high or intermediate vacuum level. At 0, 10, 21 and 28 days after packaging, residual nitrite, rancidity, pH, residual salt and pigment conversion were measured. Residual nitrite and pH were lower while nitrosopigment conversion was higher in bacon packaged with the high-barrier film. Vacuum level, however, had no effect on any measured characteristic. The sorbate/reduced nitrite cure resulted in lower pigment conversion, lower residual nitrite, and a higher TBA number.     

Effect of Belly Handling (Chilled, Frozen, Prerigor) and Smoking Delay on Regular and Sorbate-Cured Bacon

Bellies from three handling methods; fresh, frozen, or prerigor were cured with either 40 ppm sodium nitrite/0.26% potassium sorbate or 120 ppm sodium nitrite. After pumping, one group of bellies was processed (cooked and smoked) immediately, and the remaining group was held 72 hr before processing. Residual nitrite was significnatly higher in regular cure bacon and in bellies processed immediately. By 28 days after packaging, little difference was seen in residual nitrite as a result of any treatment. Regular bacon and immediate processing resulted in greater nitrosopigment conversion. Prerigor bacon had greater pigment conversion and greater residual NaCl concentrations while fresh and frozen bellies were similar. Nitrosamine levels were not influenced by belly handling variables.     

Relationship between the solubility,dosage and antioxidant capacity of carnosic acid in raw and cooked ground buffalo meat patties and chicken patties

Antioxidant capacity of oil soluble and water dispersible carnosic acid (CA) extracted from dried rosemary leaves using HPLC was evaluated at two different dosages (22.5 ppm vs 130 ppm) in raw and cooked ground buffalo meat patties and chicken patties. Irrespective of total phenolic content, CA extracts reduced (p < 0.05) the thiobarbituric acid reactive substances (TBARS) by 39%–47% and 37%–40% in cooked buffalo meat and chicken patties at lower dosage (22.5 ppm) relative to control samples. However, at higher dosage (130 ppm) the TBARS values were reduced (p < 0.05) by 86%–96% and 78%–87% in cooked buffalo meat and chicken patties compared to controls. The CA extracts were also effective in inhibiting (p < 0.05) peroxide value and free fatty acids in cooked buffalo meat and chicken patties. The CA extracts when used at higher dosage, were also effective in stabilizing raw buffalo meat color.     

Effect of Belly Composition on Sorbate-Cured Bacon

A comparison was made between fat-type and lean-type bellies cured with either 40 ppm sodium nitrite/0.26% potassium sorbate or 120 ppm sodium nitrite. Residual nitrite levels were higher in fat bacon regardless of cure. Sorbate-cured bacon resulted in signiticantly higher TBA numbers than did regular-cure bacon. Nitrosopigment to total pigment ratio did not vary with cure, but did remain significantly higher in fat bacon and roughly paralleled residual nitrite levels. Analysis for nitrosamines indicated greater concentrations in fat bellies compared to lean. Nitrosamines were suppressed though not eliminated, by the sorbate cure in both fat and lean bellies.     

INDIVIDUAL AND COMBINED LISTERICIDAL EFFECTS OF SODIUM LACTATE, POTASSIUM SORBATE, NISIN AND CURING SALTS AT REFRIGERATION TEMPERATURE

The individual and combined antilisterial activity of the preservatives sodium lactate (4%), potassium sorbate (0.3%) and nisin (400 IU/ml), in either the presence or absence of the curing salts nitrite (125 ppm) and polyphosphate (0.5%), was assessed in buffered BHI broth (pH 5.5) during incubation at 4C. A cocktail of the strain Listeria monocytogenes NCTC 7973 and two food derived strains was used as the inoculum in challenge studies. In the absence of the preservatives , L. monocytogenes grew in the presence of polyphosphate but not in the presence of nitrite or a combination of nitrite and polyphosphate. The antilisterial action of nitrite was predominantly bacteriostatic in nature. Lactate acting alone, or in the presence of curing salts, produced a bacteriostatic effect. Sorbate acting alone had a bacteriostatic effect. Sorbate acting in the presence of nitrite or nitrite and polyphosphate produced a marked listericidal effect, reducing the population by 6.7 logs and 5.4 logs, respectively. Nisin acting alone produced an almost immediate 90% listericidal response (1 log population decrease), but initial numbers were restored within 14 days by regrowth. Regrowth was eliminated when nisin was used in combination with lactate, nitrite or nitrite and polyphosphate. The combination of lactate and sorbate offered no advantage over the use of sorbate alone. Sorbate and nisin acting in combination produced an enhanced listericidal effect, which was also seen in the presence of curing salts, but was delayed. No listericidal advantage over sorbate-nisin combination was achieved through the use of the lactate-sorbate-nisin combination. The combined use of sorbate and nisin offers promise as a means of eliminating L. monocytogenes from low pH cured meat products. The efficacy of this preservative combination remains to be evaluated in a meat system before its practical application can be considered .     

INHIBITION OF AEROBIC AND ANAEROBIC GROWTH OF STAPHYLOCOCCUS AUREUS IN A MODEL SAUSAGE SYSTEM

Sodium nitrite, potassium sorbate, and glycerol monolaurate all inhibited anaerobic growth of Staphylococcus aureus more than its aerobic growth in an agar-meat model sausage system, and all were more inhibitory when lactic acid was added. Whereas anaerobic growth of S. aureus was inhibited by concentrations of 100, 2500, and 2500 ppm, respectively, of nitrite, potassium sorbate, and glycerol monolaurate, corresponding concentrations of 150, 5000, and 5000 ppm were required to inhibit aerobic growth ((20 meq lactic acid added).
Sorbic acid, a 3:1 mixture of sorbic acid and glycerol monolaurate by weight, and butylated hydroxyanisole (BHA), however, did not show differential inhibitory effects toward aerobic and anaerobic growth of S. aureus and also were more effective inhibitors with addition of lactic acid. Sorbic acid suppressed staphylococcal growth in the model sausage system at 500 ppm, the mixture of sorbic acid and glycerol monolaurate at 750 ppm, and BHA at 10,000 ppm (20 meq lactic acid added).     

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.     

Physical and Sensory Properties of Chicken Patties Made with Varying Proportions of White and Dark Spent Fowl Muscle

Spent fowl was flaked and formulated to include: (1) 100% dark meat; (2) 75% dark meat, 25% white meat; (3) 50% dark meat, 50% white meat; (4) 25% dark meat, 75% white meat; and (5) 100% white meat. Patties were made and half from each formulation were coated with calcium alginate. Proximate analysis of patties before and after cooking, calculation of cooking loss, and evaluations for textual properties and sensory attributes were performed. As the proportion of white meat increased, the samples contained less fat, had less cooking loss and shrinkage, and received higher sensory preference scores. Patties coated with calcium alginate were more desirable in texture, flavor, juiciness, and overall palatability as compared to the controls.     

Effect of carnosine, salt and dietary vitamin E on the oxidative stability of chicken meat

The effect of carnosine on lipid and cholesterol oxidation in salted chicken thigh meat and its relationship to dietary α-tocopherol supplementation was examined. Broilers (Cobb 500) were fed diets with a basal (30 mg kg(-1)) or supplemental (200 mg kg(-1)) level of α-tocopheryl acetate for 6 weeks. Thigh meat patties were prepared with carnosine (1.5%), salt (1%) or salt plus carnosine. Salt accelerated lipid and cholesterol oxidation following cooking and refrigerated storage. However, carnosine inhibited lipid and cholesterol oxidation in salted patties. Dietary α-tocopherol supplementation also reduced the extent of lipid and cholesterol oxidation in salted patties. The combination of carnosine and dietary α-tocopherol resulted in the greatest lipid and cholesterol stability in salted meat.     

Effect of antioxidants on stabilization of meat products fortified with n-3 fatty acids

The effects of an n-3 oil emulsion, with and without added antioxidants, on lipid oxidation in n-3 polyunsaturated fatty acid (PUFA)-fortified meat products were studied. An emulsion of n-3 PUFAs was prepared (25% algal oil, 2.5% whey protein isolates, 10mM sodium citrate, 0.2% potassium sorbate, 500ppm of 70% mixed tocopherols, 100μM EDTA, pH 3, pasteurized at 75°C for 30min) and incorporated into fresh ground turkey, and fresh pork sausage (20% fat) to achieve a concentration of 500mg n-3 PUFA/110g meat. An antioxidant combination containing rosemary (0.2% w/w; radical quencher), citrate (0.5% w/w; sequestrant) and erythorbate (1g/kg product; reductant) was prepared and incorporated into ground turkey patties (5cm dia, 1.5cm thick) or fresh pork sausages (5cm dia, 1.5cm thick). Meat products were stored at 4°C or -18°C and analyzed for color (L*, a*, b* values), lipid oxidation (TBARS and lipid hydroperoxides) and n-3 PUFA profile. a* Values of refrigerated ground turkey patties decreased with storage, and an antioxidant combination effect was observed after 4 days (P<0.05). For fresh pork sausages at 4°C, control+antioxidant (CON+ANTI), and n-3+antioxidant (n-3+ANTI) groups showed greater a* values than controls (CON) indicating that the antioxidant combination stabilized meat color. TBARS and lipid hydroperoxides of both n-3 PUFA-enhanced meat products increased with storage (P<0.05); there were no significant changes in TBARS or lipid hydroperoxides for treatments containing the antioxidant combination (P<0.05). The actual level of n-3 PUFA incorporation in both meat products was greater than 87%; n-3 PUFA concentrations did not change within any treatment during storage (P>0.05). These results provide support for including antioxidant protection in n-3 PUFA fortified meat products.     

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.     

Evaluation of the effects of sodium chloride,potassium sorbate,nisin and lysozyme on the probability of growth of Clostridium sporogenes

The aim of this study was to evaluate the combined effect of salt (sodium chloride, 0–8% w/v), sorbate (potassium sorbate, 0–4.5% w/v), nisin (0–500 ppm) and lysozyme (0–500 ppm) on the survival of Clostridium sporogenes as a non‐toxigenic surrogate of Clostridium botulinum in terms of the probability of growth by using a central composite rotatable design. The results indicated that salt and sorbate were the most effective factors in preventing the growth of Cl. sporogenes in high‐moisture (>95%) and low‐acid conditions. The probability of growth of Cl. sporogenes in broth was reduced by combinations of salt and sorbate. Nisin and lysozyme had insignificant effects on the probability of growth of Cl. sporogenes (P > 0.05). Lysozyme individually and in combination with nisin had no inhibitory effect on Cl. sporogenes. Overall, the addition of sorbate and lysozyme may allow the salt concentration to be reduced while preventing growth.     

The effect of pH,sodium chloride,sodium nitrite and storage temperature on the growth of Clostridium perfringens and faecal streptococci in laboratory media

The effects of salt concentration (1–12% w/v) in combination with unheated sodium nitrite (0–400 μg/ml) on growth of mixed strains of Clostridium perfringens and of faecal streptococci at three pH values (5.6, 6.2, 6.8) and storage temperatures ranging from 10°C to 35°C is reported. At pH 6.2, following storage at 15°C, 1% salt and 50 μg/ml nitrite inhibited growth of C. perfringens. At 20°C and pH 6.2, 200 μg/ml nitrite plus 3% salt, or 50 μg/ml plus 4% salt were required to inhibit growth. Growth of C. perfringens was prevented by levels of curing salts used commercially providing the pH was 6.2 or below. At pH 6.8 or above at least 4% salt and 50 μg/ml nitrite was required to prevent growth at 20°C. The faecal streptococci grew in medium containing 6% salt and 400 μg/ml nitrite irrespective of pH or storage temperature. In 8% salt growth was prevented by storing at or below 17.5°C or, if pH was 6.2 or lower, by adding 200 μg/ml nitrite irrespective of storage temperature. Growth of faecal streptococci was not controlled by concentrations of curing salts which would be acceptable in meat products.     

鸡肉卤制过程中卤汤循环使用时安全性的控制研究

控制鸡肉卤制过程中卤汤循环使用时的安全性,为稳定鸡肉品质及工业生产时使用添加剂补料提供方法参考和科学依据。本研究以鸡翅根为原料,控制每次卤汤中山梨酸钾、D-异抗坏血酸钠和氯化钠含量以及料液比相同,探讨卤汤循环使用时配料(山梨酸钾、D-异抗坏血酸钠)对鸡肉的抑菌效果和抗氧化作用以及卤汤中山梨酸钾、D-异抗坏血酸钠、pH、TBARS、亚硝酸盐的变化规律并进行曲线拟合预测趋势。结果表明:卤汤中山梨酸钾添加量为0.375 g/kg、D-异抗坏血酸钠添加量为200 mg/100 g时,随着卤制次数的增加,鸡肉卤制品的菌落总数显著降低(p0.05),卤制5次后其数值降至103 cfu/g;TBARS变化不显著(p0.05);山梨酸钾和D-异抗坏血酸钠均呈现波动变化,幅度稳定在2%。随着卤制次数增多,卤汤酸度显著增加(从6.7到5.79),TBARS增加(从0到0.614mg/kg),亚硝酸盐含量升高(从0到0.0845mg/kg)。三个测定指标(pH、TBARS、亚硝酸盐含量)采用高斯拟合得出随卤制次数的增加变化趋稳,能控制鸡肉卤制过程中卤汤循环使用时的安全性。     

Addition of tea catechins and vitamin C on sensory evaluation, colour and lipid stability during chilled storage in cooked or raw beef and chicken patties

The effects of addition of tea catechins (TC) and vitamin C (VC) on sensory evaluation, colour and lipid stability in cooked or raw beef and chicken meat patties during refrigerated storage were studied. Fresh beef striploin and chicken breast muscles were minced, following removal of external fat and connective tissue. Following mincing, beef and chicken were assigned to one of the following five treatments: control (meat treated with no antioxidant); TC200, meat plus 200 mg TC/kg muscle; TC400, meat plus 400 mg TC/kg muscle; VC200, meat plus 200 mg VC/kg muscle, VC400, meat plus 400 mg VC/kg muscle. Sodium chloride (1%) was added to all samples. Patties (125 g portions), formed from the above-treated minced meat, were oven cooked, cooled, and packaged in 30% CO₂:70% N₂. Fresh raw beef and chicken patties were packaged in 80% O₂:20% CO₂. All samples were stored for up to 7 days under fluorescent lighting at 4 °C. Sensory parameters (colour, flavour, taste, tenderness and overall acceptability) were evaluated on cooked beef and chicken patties after 1, 3 and 6 days of storage. Surface colour (Hunter L, a and b values), and lipid oxidation (2-thiobarbituric acid reactive substances) were measured on days 1, 3 and 6 of storage for cooked meats and on days 2 and 7 for raw beef and chicken. Tea catechins addition (200 or 400 mg/kg) to minced meat caused (P < 0.05) discolouration in cooked beef and chicken meat patties and significantly reduced (P < 0.001) lipid oxidation in cooked or raw beef patties compared to the control. Beef, either raw or cooked, was more susceptible (P < 0.01) to oxidation compared to chicken. Raw meat stored in high oxygen conditions was more susceptible to lipid oxidation than cooked meat stored in anaerobic conditions. Tea catechins treatments (TC200 and TC400) inhibited (P < 0.05) lipid oxidation in raw beef to a greater extent than vitamin C treatments (VC200 and VC400). These results indicate that tea catechins are potent natural antioxidants and exhibit greater antioxidant efficacy compared to vitamin C.     

Use of natural antimicrobials to improve the control of Listeria monocytogenes in a cured cooked meat model system

Concern about nitrite in processed meats has increased consumer demand for natural products manufactured without nitrite or nitrate. Studies on commercial meat products labeled as "Uncured" and "No-Nitrite-or-Nitrate-Added" have shown less control of nitrite in these products and greater potential growth of bacterial pathogens. To improve the safety of the "naturally cured" meats, several natural ingredients were studied in a cured cooked meat model system (80:20 pork, 10% water, 2% salt, and 150 or 50 ppm ingoing sodium nitrite) that closely resembled commercial frankfurters to determine their inhibitory effect on Listeria monocytogenes. Results showed that cranberry powder at 1%, 2% and 3% resulted in 2-4 log cfu/g less growth of L. monocytogenes compared to the control with nitrite alone (P<0.05). Other natural compounds, such as cherry powder, lime powder and grape seed extract, also provided measureable inhibition to L. monocytogenes when combined with cranberry powder (P<0.05).     

迷迭香提取物对等离子体处理鸡胸肉饼脂质氧化及品质影响研究

研究了不同浓度迷迭香提取物(RE)对包装内介质阻隔放电(DBD)冷等离子体(CP)处理的鸡胸肉饼脂质氧化及品质特性的影响。鸡肉饼在70 kV条件下DBD-CP处理180 s,在4 ℃贮藏的第0天和第5天测定菌落总数、pH值、颜色和脂质氧化。结果表明,CP处理在0 d时对鸡肉饼的菌落总数无影响,但贮藏5 d后,CP处理使菌落总数显著降低,同时CP处理也加剧了鸡肉饼的脂质氧化。添加0.2%和0.3% RE可降低CP处理和非CP处理鸡肉饼的菌落总数,各浓度RE对CP处理和非CP处理鸡肉饼脂质氧化均有抑制作用,且浓度越高,效果越好。添加RE使鸡肉饼的L*值降低而a*值和b*值升高,添加0.3% RE使鸡肉饼pH值降低。综上所述,迷迭香提取物可用于抑制CP加工肉类的微生物生长,同时能控制脂质氧化,具有较好的应用前景。     

Sanitizing effect of salts on experimentally inoculated organisms on pork carcasses

Pork forequarters procured from freshly slaughtered animals were decontaminated with hot water and inoculated with Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Yersinia enterocolitica, Listeria monocytogenes, Serratia marcescens, Pseudomonas aeruginosa and Proteus vulgaris. The forequarters were individually spray washed with 5% potassium sorbate and a combination of 5% sodium chloride and 2.5% each of sodium acetate, sodium citrate, sodium lactate and potassium sorbate solutions. The total viable count (TVC) of the treated meat samples was reduced by 0.96 and 1.31 log units by spraying with salt and salt combination respectively with marginal changes in colour and odour scores. Inoculated organisms were found to be highly sensitive to salt combination treatment as compared to potassium sorbate alone. Shelf-life of salt and salt combination treated samples was increased to 8 and 11 days as against 4 days in untreated samples. Carcass washing with salt and salt combination was found to be suitable for extension of shelf-life and improvement in the sensory and microbiological quality of meat.