Control of Listeria Monocytogenes by Lauric Arginate on Frankfurters Formulated with or without Lactate/Diacetate

ABSTRACT:  Listeria monocytogenes  (Lm) is a food safety concern that can be associated with ready-to-eat (RTE) meat and poultry products because of its persistence in the processing environment. Listeriosis has a fatality rate of 28% in immuno-compromised individuals. RTE meats receive a lethal heat treatment but may become contaminated by Lm after this treatment. Federal regulators and manufacturers of RTE meats are working to find additional ways to control postprocess contamination by Lm in RTE meats. This research was initiated to validate combinations of antimicrobials that would produce an immediate lethality of at least 1 log of Lm on artificially contaminated frankfurters, and also suppress Lm growth to less than 2 logs throughout the extended shelf life at refrigerated temperatures (4 °C). Based on our studies, 22-ppm lauric arginate (LAE, ethyl-N-dodecanoyl-L-arginate hydrochloride) gave more than a 1-log reduction of Lm surface inoculated onto frankfurters within 12 h. The combination of either 1.8%/0.13% or 2.1%/0.15% potassium lactate/sodium diacetate (L/D) in combination with 22 ppm LAE caused more than a 2-log reduction at 12 h. Storage studies revealed that complementary interactions of L/D and LAE also met the 2nd requirement. This combination initially reduced Lm by 2 logs and suppressed growth to less than 2 logs even at the end of the 156-d storage life for frankfurters. These results confirmed that the combination of L/D with LAE as a postprocessing–prepackaging application could be useful in complying with the USDA's Alternative 1 that requires validation for the control of Lm on RTE frankfurters.     

Sensory Characteristics of Frankfurters as Affected by Fat, Salt, and pH

Acceptable processing and flavor profile characteristics of frankfurters were achieved near a pH of 6.0. As salt increased, hardness, juiciness, saltiness, and flavor intensity scores increased. As fat increased, juiciness scores decreased (at salt levels > 1.3%) due to substitution of water for fat. In addition, increased fat resulted in decreased off-flavor. Model predictions suggested that acceptable frankfurters could be manufactured with a minimum of 11.25% fat and 1.3% salt at pH 6.0.     

N-Nitrosodimethylamine Formation in Cooked Frankfurters Containing Alaska Pollock (Theragra chalcogramma) Mince and Surimi

Studies were conducted to determine the feasibility of using Alaska pollock mince as a partial substitute for red meats in the formulation of frankfurters. Studies included the effects of fish form (unwashed and washed mince and surimi), percentage substitution (15 and 50) and five different methods of cooking the fish-meat franks on their N-nitrosodimethylamine (NDMA) content. The amount of formed NDMA depended on the method of cooking. Broiling and frying generated the highest levels. Microwave and boiling generated the lowest levels of NDMA, which were equivalent to the level in uncooked franks. Broiling was observed to increase the amount of dimethyl-and trimethylamine formed.     

Effects of Organogel Hardness and Formulation on Acceptance of Frankfurters

Different organogel formulations used as beef fat (BF) replacement (0%, 20%, 40%, 60%, and 80%) were utilized to optimize the mechanical properties of frankfurters. Organogels, made of canola oil (CO), included different concentrations of ethyl cellulose (EC) and sorbitan monostearate (SMS). They consisted of: 8% EC + 1.5% SMS referred to as organogel‐I (OG‐I), 8% EC + 3.0% SMS (OG‐II), and 10% EC + 1.5% SMS (OG‐III), which were found promising in a previous study when used at 100% replacement. Replacement of BF with organogels at all levels could bring down the very high hardness values (texture profile analysis and sensory) of frankfurters prepared using CO by itself, relative to the BF control. OG‐I and OG‐II quantity had no significant effect on hardness and springiness, being similar in many cases to the BF and lower than the CO control. Shear force values of all organogel treatments were not significantly different from one another, and were between the BF and CO controls. Smokehouse yield showed a pattern of decreasing losses with increasing organogel replacement level. Sensory analysis revealed that using CO by itself significantly increased hardness, but structuring the oil (via organogelation), brought it down to the BF control value in all OG‐I and OG‐II formulations. Juiciness was significantly reduced by using liquid oil but increased with raising the amount of organogels. Oiliness sensation increased with higher organogel substitution and was actually higher than the beef control. The study demonstrates the potential use of vegetable oil structuring in replacing the more saturated BF in emulsion‐type meat products.     

Use of culled goat meat in frankfurter production – effect on sensory quality and technological properties

Four different levels (25–100%) of culled goat meat were used in frankfurter formulation (frankfurters G25, G50, G75 and G100) instead of beef (CON). Technological properties, fatty acid profile and sensory properties were examined during the 6-week cold storage. The formulation had significant impact of fatty acids profile – n-6/n-3 ratios progressively decrease from 14.63 in CON to 6.63 in G100. Higher goat meat content led to progressively higher lightness and lower redness in frankfurters. This was also observed by consumers but not negatively perceived. Check-all-that-apply (CATA) analysis shows that more than 80% of consumers marked pleasant colour as present in goat frankfurters and CON. The similar was observed for pleasant appearance, pleasant odour, tasty, soft and juicy. Moreover, atypical taste and odour were mostly not marked as present (73.8% and 62.5%, respectively). The panellists pointed at G50 as the most preferred, while consumers most frequently marked G75.     

Effect of Salts of Organic Acids on Listeria monocytogenes,Shelf Life,Meat Quality,and Consumer Acceptability of Beef Frankfurters

The objective of this study was to evaluate anti‐listerial efficacy of salts of organic acids, and their impact on the quality of frankfurters. Beef frankfurters were manufactured by incorporating organic acids in 5 different combinations: (1) control (no marinade addition; C); (2) sodium lactate (2% wt/wt; SL); (3) potassium lactate (2% wt/wt; PL); (4) sodium citrate (0.75% wt/wt; SC); and (5) sodium lactate (2% wt/wt)/sodium diacetate (0.25% wt/wt; SL/SD). Cooked frankfurters were inoculated with streptomycin‐resistant (1500 μg/mL) L. monocytogenes (7 log₁₀ CFU/frank). Inoculated and noninoculated frankfurters were vacuum packaged and stored at 4 °C. Samples were taken weekly up to 10 wk for estimation of L. monocytogenes as well as aerobic plate count (APC) and psychrotrophs (PSY), respectively. Total of 2 independent trials of the entire experiment were conducted. Noninoculated beef frankfurters were evaluated weekly by untrained sensory panelists for 7 wk. SL, PL, and SC treatments did not (P > 0.05) adversely affect consumer acceptability through 8 wk although, SL/SD treatment was significantly (P ≤ 0.05) less preferred across all sensory attributes. SL/SD treatment negatively affected product quality, but was able to control APC, PSY, and L. monocytogenes levels. SC performed similar to the control throughout the 8, 9, and 10 wk storage periods, providing no benefit for inhibiting L. monocytogenes (increasing from 7 logs CFU/frank to 10 logs CFU/frank throughout storage) or extending shelf life of the beef frankfurters. In conclusion, 2% SL and PL, and 2% SL/0.25% SD may be effective L. monocytogenes inhibitors (maintaining inoculation levels of 7 logs CFU/frank during storage), but changes in SL/SD treatment formulation should be studied to improve product quality.     

Thermal Inactivation of Escherichia coli O157:H7 in Cooked Turkey Products

Survival of Escherichia coli O157:H7 when heated in commercial-type turkey products was determined. Thermal death times (TDT) were determined at 52–60°C in ground turkey with no additives, 3% fat; ground turkey with no additives, 11% fat; turkey ham batter, 11% fat; turkey frank batter, 17% fat; and turkey sausage batter, 31% fat. Mean D₅₂-values ranged from 44.9 to 116 min; D₅₅-values from 6.63 to 39.4 min; D₅₇-values from 2.20 to 11.7 min; D₆₀-values from 0.68 to 5.86 min. At all temperatures, survival of E. coli O157:H7 was greater in formulated products than in turkey meat with no additives. Greatest survival occurred in the turkey frank batter. Using our z-value data, times to provide a 5 D kill of E. coli O157:H7 in turkey franks cooked at 60°C, 65.6°C, or 71°C would be 26, 3.1, or 0.37 min, respectively.