Comparative proteomic analyses to investigate premature browning in high­oxygen modified atmosphere packaged beef patties.

This study compared the proteomics of beef patties under high­oxygen modified atmosphere packaging (HiOx-MAP) and vacuum packaging (VP) during heating. The color and oxidation stability of fresh patties, and myoglobin denaturation of cooked patties were also measured. The results suggested that HiOx-MAP patties contained more oxymyoglobin in fresh meat and had higher myoglobin denaturation during heating than VP patties, resulting in premature browning (PMB) during cooking. Proteomic analysis found that the overabundance of proteasome subunit beta type-2 (PSMB2) and peroxiredoxin-2 (PRDX2) in HiOx-55 °C, which can remove the damaged proteins and inhibit oxidation respectively, are of benefit to meat color stability during storage, however, this was still insufficient to inhibit the occurrence of PMB during cooking. The high abundance of lamin B1 (LMNB1) in VP-55 °C can maintain the stability of meat color. This research provides greater understanding, based on proteomic perspectives, of the molecular mechanism of PMB.

Impact of nitrite-embedded packaging film on quality and sensory attributes of alternatively-cured and nitrite-free bologna.

The objectives were to determine the effects of post-thermal processing nitrite-embedded film (NEF) packaging on the quality attributes of alternatively-cured (nitrite from celery juice powder (AC)) and nitrite-free bologna. Attributes evaluated included lipid oxidation, instrumental color, pigment concentration, and sensory properties such as cured meat flavor, aroma, and color. Three bologna formulations, each packaged with two packaging films were produced. A conventionally-cured control formulation (with nitrite from sodium nitrite; CON), a nitrite-free formulation (UCC), and an alternatively cured formulation (nitrite from cultured celery juice powder; AC) were packaged in conventional (CF) or nitrite-embedded (NEF) film. Instrumental a* values (measured during both light and dark storage at intervals of 7 or 14 days over 126 days of storage) and cured pigment concentration (measured at 14-day intervals over 84 days of storage) were significantly greater (P < 0.05) for the UCC-NEF treatment compared to its conventional film counterpart, UCC-CF. No significant differences (P > 0.05) for lipid oxidation (TBARS values) were observed with NEF. Trained sensory panelists, who evaluated samples at 14-day intervals over 70 days of storage, found significantly greater (P < 0.05) cured aroma, cured flavor, pink color and less off-flavor for uncured bologna packaged in NEF compared to conventional film. For the uncured bologna formulation, NEF packaging provided cured meat attributes comparable to the control formulation that included nitrite. This is the first time that cured aroma and flavor have been observed when nitrite from packaging film is added to a cooked meat product under anaerobic conditions.

Survival of Clostridium perfringens, Staphylococcus aureus and Salmonella enterica in alternatively cured bacon during cooking and process deviations.

Pork bellies were injected with four different alternative curing brines. The bellies were inoculated on the surface and at a depth of 1 cm with multiple strains of Clostridium perfringens, Staphylococcus aureus and Salmonella enterica. The bellies were processed using either a standard process cycle or an interrupted process cycle to simulate a process deviation. Additionally, laboratory simulation of the same cycles was conducted where surface inoculated pork belly samples (22 ± 1 g) were processed in a circulating water bath. Microbiological populations were determined at the beginning, mid-point and end of the cycles, and the change in population was calculated for each bacterium at each time point, by comparing the population to the initial inoculated population. Irrespective of the brine or process cycle, the populations of all of the inoculated bacteria on both the surface and interior samples had decreased by the end of the process. There was no difference in the reductions in bacterial populations for all of the inoculated bacteria by brine type or by sample location (P > 0.30). There were differences in the microbial population reductions for C. perfringens attributable to the processing cycle (P < 0.001), with less population reductions associated with the standard cycle when compared to the interrupted cycle. However, no differences (P > 0.10) were observed in the population reductions between the two processing cycles for either S. aureus or S. enterica.

Effects of Calcium Salts on the Physicochemical Quality of Cured Beef Sausages during Manufacturing and Storage: A Potential Calcium Application for Sausages with Alginate Casings.

The impacts of adding calcium chloride (CaCl2) and calcium lactate (CaLac) with different concentrations (0%, 0.2%, 0.4%, and 0.7%) on the physicochemical properties of cured beef sausages were investigated in this study. Meat color, pH, lipid oxidation, and cooking loss were measured at respective manufacturing stages (ground beef, raw chopped batter, and after cooking). Additionally, meat color, pH, lipid oxidation, nitrosylhemochrome, residual nitrite, and texture profiles of vacuum-packaged sausages were evaluated during seven days of storage. Compared with the control (no Ca added), both calcium salts resulted in deteriorative color and texture properties, and promoted pH decline, cooking loss, and lipid oxidation of sausages during manufacturing and storage. However, increased calcium salt addition led to the reduction of residual nitrite over time. Compared to CaCl2 addition, 0.2-0.4% CaLac resulted in greater redness and oxidative stability and softer texture. These results may be useful when considering calcium salt additions in sausages, for the purpose of co-extruded sausages coated with alginate where Ca salts are used to form the casing during the co-extrusion of the sausages.

Pork frankfurters prepared with hydrolyzed whey: Preliminary product quality aspects and inhibitory activity of the resulting peptides on angiotensin-converting enzyme.

The objective of this study was to assess the addition of whey protein hydrolysate (WH) on quality and antihypertensive potential of pork frankfurters, as the first step in development of a functional meat product. A hydrolyzed whey protein solution was incorporated in the frankfurter formula according to the following treatments: T0 (30% water), T1 (10% WH, 20% water), T2 (20% WH, 10% water) and T3 (30% WH). Addition of up to 30% WH increased lightness and yellowness, decreased hardness and chewiness by 15% and shear force by 43%, with no effect on pH (6.36) and cooking yield (93%). The WH addition resulted in an increase in the antihypertensive potential (IC50 258.78 µg/mL) relative to the T0 (IC50 1548.25 µg/mL). Cold storage of the product with 30% WH did not impact physicochemical quality, nor did it modify the antihypertensive potential. Incorporation of whey hydrolysate into pork frankfurters could be an option for providing antihypertensive peptides in food for health-oriented consumers.

Rheological characteristics of mechanically separated chicken and chicken breast trim myofibril solutions during thermal gelation.

Mechanically separated chicken (MSC) was obtained by two different separation methods (MSC1, Beehive separator, 3-5 d-old bones; MSC2, Poss separator, fresh bones) and compared to chicken breast trim (CBT). Rheological attributes of myofibrillar protein solutions during thermal gelation and cooling were evaluated. All sources exhibited gelation with increased temperature (decreased δ). In all three treatments, a peak, decline, and subsequent increase in both the G' and G″ was observed in the 50-55 °C range, with peak values being higher for CBT than for both MSCs. G' slopes on both sides of the peak (S2, S3) and following the decline (S4) were significantly different between CBT and both MSCs (P < 0.05) and indicated greater instability of the solid-like structure in the temperature range of 50-55 °C (myosin rod denaturation). Myofibrillar protein profiles confirmed fiber type differences among materials, as well as greater myosin fragmentation or modification in the MSC samples.

Evaluation of citrus fiber as a natural replacer of sodium phosphate in alternatively-cured all-pork Bologna sausage.

The effects of sodium tripolyphosphate replacement with citrus fiber on color, texture, lipid oxidation, and sensory characteristics of an alternatively-cured all-pork Bologna sausage during 98 d of storage at storage 0-1 °C were studied. Replacement of sodium phosphates in processed meat with citrus fiber could enable manufacturers to make their products more consistent with the current "clean label" trend. The Bologna sausage was assigned one of five treatments: sodium tripolyphosphate control (0.38%), no-sodium-tripolyphosphate control, or one of several citrus fiber levels (0.50%, 0.75%, 1.00%). Citrus fiber treatments resulted in Bologna sausage with acceptable technological parameters, as indicated by similar cook/chill yields and emulsion stability compared to the sodium tripolyphosphate control. The results showed the replacement of sodium tripolyphosphate with citrus fiber did not significantly alter most physical, chemical or sensory characteristics of the Bologna sausage during refrigerated storage.

Replacement of pork fat in frankfurter-type sausages by soybean oil oleogels structured with rice bran wax.

The objective of this study was to assess the impact of replacing pork backfat with rice bran wax oleogels on the organoleptic properties of frankfurter-type finely-comminuted sausages. Frankfurters were formulated using the following treatments as lipid replacement: 1) pork fat (PF); 2) soybean oil (SBO); 3) 2.5% rice bran wax oleogel (2.5 RBW); 4) 10% rice bran wax oleogel (10 RBW); and 5) 2.5% rice bran wax oleogel sheared less during frankfurter production (RBW/LS). In general, control PF was darker and redder than other treatments. TPA revealed oleogel treatments to be similar (P > .05) to pork fat treatment for firmness, chewiness, and springiness. Additionally, sensory evaluation revealed that replacing pork fat did not influence cured frankfurter aroma, but cured frankfurter flavor was significantly reduced (P < .05). Furthermore, lipid oxidation significantly (P < .05) differed between PF and 10 RBW. The results show that rice bran wax oleogels have the potential to successfully replace pork fat in comminuted products.

Quality evaluation of low fat bologna-type meat product with a nutritional profile designed for the elderly.

The objective of this work was to evaluate the quality of a bologna-type meat product designed for the elderly. Treatments were: control, without addition of cranberries (C), prunes (P), pecan nuts (N) or flaxseed (F); NP, with 5% N+5% P; FC, with 5% F+5% C; NC, with 5% N+5% C; FP, with 5% F+5% P. These formulations resulted in a product with high protein, low SFA and high antioxidant activity. Treatments with pecan nuts had higher MUFA while those with flaxseed had higher polyunsaturated fatty acids (PUFA). Treatments with pecan nuts and flaxseed had higher PUFA/SFA ratios, but only those with flaxseed had very low n6/n3 ratios when compared to the control. Although treatments showed acceptable scores (>5.4), they were lower than the control. A combination of these non-traditional ingredients could be used to develop a meat product for older adults to provide a better nutritional profile with acceptable sensory properties.

Inhibition of Listeria monocytogenes by Buffered Dry Vinegar in Reduced-Sodium Ready-to-Eat Uncured Turkey Stored at 4°C.

A reduced-sodium ready-to-eat (RTE) uncured turkey was manufactured with buffered dry vinegar treatments to validate the inhibition of Listeria monocytogenes and spoilage microflora and to determine the effects on sensory and quality attributes. Samples were stored at 4°C for 12 weeks, and the study was independently replicated three times. Two different five-strain inocula of L. monocytogenes obtained from different sources were used for evaluating the efficacy of the buffered dry vinegar treatments. The results showed that 0.6 and 0.8% buffered dry vinegar with a sodium base (BDV-SB) and buffered dry vinegar with a potassium base (BDV-PB) at 0.7 and 0.9% controlled L. monocytogenes for 12 weeks. The untreated control product containing no buffered dry vinegar showed >1 log increase in L. monocytogenes populations counts at the end of 2 weeks. Statistical analysis confirmed that the dry vinegar treatments inhibited (P > 0.05) the growth of L. monocytogenes compared with the untreated control. No significant differences (P > 0.05) were seen in the inhibition of L. monocytogenes between the two different five-strain inocula. Instrumental color results showed no significant differences between the treatments. Purge loss results showed no significant differences between the dry vinegar treatments, but significant differences were seen between the untreated control and dry vinegar treatments at a few testing intervals. The overall results indicated that the dry vinegar ingredients (6.66 to 8.83 mM acetic acid in the finished product) were effective in inhibiting L. monocytogenes obtained from multiple sources in reduced-sodium RTE uncured turkey stored at 4°C without adversely impacting the quality attributes.

Can supplemental nitrate in cured meats be used as a means of increasing residual and dietary nitrate and subsequent potential for physiological nitric oxide without affecting product properties?

The effects of formulated sodium nitrate plus supplemental nitrate (SN) from celery juice powder on residual nitrite, residual nitrate, rancidity, microbial growth, color, sensory properties, and proximate composition of frankfurters, cotto salami and boneless ham during storage (1°C) were studied. The products were assigned one of two treatments, which were each replicated twice: control (156ppm sodium nitrite) or SN (156ppm sodium nitrite and 1718ppm sodium nitrate in combination with 2% VegStable 502). Sensory parameters and proximate composition were measured once for each replication. All other analytical measurements were conducted at regular intervals for 97-98days. The SN showed no increase in residual nitrite compared to the control. No changes (P>0.05) were observed in residual nitrate during storage for any of the products. The results showed that addition of SN did not significantly alter most physical, chemical or microbial properties of cured meat products during refrigerated storage, but some product dependent sensory effects were observed.

Effects of adding red wine on the physicochemical properties and sensory characteristics of uncured frankfurter-type sausage.

The aim of this work was to evaluate the quality and sensory characteristics of RTE frankfurter-type sausage cured with celery juice powder and including red wine. Four frankfurter treatments including a conventionally cured treatment without red wine (control) and three treatments cured with pre-converted vegetable juice powder and 0%, 5% or 10% (v/w) red wine were prepared. Results showed that adding 5% red wine increased the a*-value, and the textural resilience, cohesiveness and springiness of the frankfurters, as well as decreased lipid/protein oxidation of the final products. Added wine also introduced new volatiles (alcohol and ester compounds) to the frankfurters. The principal component (PC) analysis showed that the pre-converted vegetable juice powder achieved the same effects as the conventional curing agents for typical frankfurter properties. However, the addition of excess amounts of red wine (10%) to the meat batter decreased the pH of meat batter and accelerated lipid oxidation.

Implications of Decreased Nitrite Concentrations on Clostridium perfringens Outgrowth during Cooling of Ready-to-Eat Meats.

Increased popularity of natural and organic processed meats can be attributed to the growing consumer demand for preservative-free foods, including processed meats. To meet this consumer demand, meat processors have begun using celery juice concentrate in place of sodium nitrite to create products labeled as no-nitrate or no-nitrite-added meat products while maintaining the characteristics unique to conventionally cured processed meats. Because of flavor limitations, natural cures with celery concentrate typically provide lower ingoing nitrite concentrations for ready-to-eat processed meats than do conventional cures, which could allow for increased growth of pathogens, such as Clostridium perfringens, during cooked product cooling such as that required by the U.S. Department of Agriculture. The objective of this study was to investigate the implications associated with reduced nitrite concentrations for preventing C. perfringens outgrowth during a typical cooling cycle used for cooked products. Nitrite treatments of 0, 50, and 100 ppm were tested in a broth system inoculated with a three-strain C. perfringens cocktail and heated with a simulated product thermal process followed by a typical cooling-stabilization process. The nitrite concentration of 50 ppm was more effective for preventing C. perfringens outgrowth than was 0 ppm but was not as effective as 100 ppm. The interaction between nitrite and temperature significantly affected (P < 0.05) C. perfringens outgrowth in both total population and number of vegetative cells. Both temperature and nitrite concentration significantly affected (P < 0.05) C. perfringens spore survival, but the interaction between nitrite and temperature did not have a significant effect (P > 0.05) on spore outgrowth. Results indicate that decreased nitrite concentrations (50 ppm) have increased potential for total C. perfringens population outgrowth during cooling and may require additional protective measures, such as faster chilling rates.

Investigating the control of Listeria monocytogenes on a ready-to-eat ham product using natural antimicrobial ingredients and postlethality interventions.

Ready-to-eat (RTE) meat and poultry products manufactured with natural or organic methods are at greater risk for Listeria monocytogenes growth, if contaminated, than their conventional counterparts due to the required absence of preservatives and antimicrobials. Thus, the objective of this study was to investigate the use of commercially available natural antimicrobials and postlethality interventions in the control of L. monocytogenes growth and recovery on a RTE ham product. Antimicrobials evaluated were cranberry powder (90MX), vinegar (DV), and vinegar/lemon juice concentrate (LV1X). Postlethality interventions studied were high hydrostatic pressure at 400 (HHP400) or 600 (HHP600) MPa, lauric arginate (LAE), octanoic acid (OA), and postpackaging thermal treatment (PPTT). Parameters evaluated through 98 days of storage at 4±1°C were residual nitrite concentrations, pH, a(w), and viable L. monocytogenes on modified Oxford (MOX) media. On day 1, OA, 90MX, DV, and LV1X yielded lower residual nitrite concentrations than the control, whereas HHP400, HHP600, and LAE did not. LAE, HHP400, and OA reduced L. monocytogenes population compared to the control after 1 day of storage by 2.38, 2.21, and 1.73 log10 colony-forming units per gram, respectively. PPTT did not achieve a significant reduction in L. monocytogenes populations. L. monocytogenes recovered and grew in all postlethality intervention treatments except HHP600. 90MX did not inhibit the growth of L. monocytogenes, while DV and LV1X did. Results of this study demonstrate the bactericidal properties of HHP, OA, and LAE and the bacteriostatic potential of natural antimicrobial ingredients such as DV and LV1X against L. monocytogenes.

Effects of different nitrite concentrations from a vegetable source with and without high hydrostatic pressure on the recovery of Listeria monocytogenes on ready-to-eat restructured ham.

Sodium nitrite exerts an inhibitory effect on the growth of Listeria monocytogenes. The objective of this study was to investigate the effects of various nitrite concentrations from a vegetable source with and without high hydrostatic pressure (HHP) on the recovery and growth of L. monocytogenes on ready-to-eat restructured ham. A preconverted celery powder was used as the vegetable source of nitrite. Targeted concentrations of natural nitrite investigated were 0, 50, and 100 mg/kg. HHP treatments evaluated were 400 MPa for 4 min and 600 MPa for 1 or 4 min at 12 ± 2 °C (initial temperature of the pressurization fluid). Viable L. monocytogenes populations were monitored on modified Oxford medium and thin agar layer medium through 98 days of storage at 4 ± 1 °C. Populations on both media did not differ. The HHP treatment at 600 MPa for 4 min resulted in L. monocytogenes populations below the detection limit of our sampling protocols throughout the storage period regardless of the natural nitrite concentration. The combination of HHP at 400 MPa for 4 min or 600 MPa for 1 min with natural nitrite resulted in initial inhibition of viable L. monocytogenes. Ham formulations that did not contain natural nitrite allowed faster growth of L. monocytogenes than did those with nitrite, regardless of whether they were treated with HHP. The results indicate that nitrite from a vegetable source at the concentrations used in this study resulted in slower growth of this microorganism. HHP treatments enhanced the inhibitory effects of natural nitrite on L. monocytogenes growth. Thus, the combination of natural nitrite plus HHP appears to have a synergistic inhibitory effect on L. monocytogenes growth.

Evaluation of the thin agar layer method for the recovery of pressure-injured and heat-injured Listeria monocytogenes.

A sublethally injured bacterial cell has been defined as a cell that survives a stress such as heating, freezing, acid treatment, or other antimicrobial intervention but can repair the cellular damage exerted by the stressor and later regain its original ability to grow. Consequently, sublethally injured cells are not likely to be included in conventional enumeration procedures, which could result in unrealistically low counts unless efforts are made to encourage recovery of the injured cells before enumeration. The objective of this study was to evaluate the use of the thin agar layer (TAL) method for the recovery of pressure-injured and heat-injured Listeria monocytogenes in a tryptic soy broth with 0.6% yeast extract system. Pressure injury consisted of treatment of a culture of mixed L. monocytogenes strains with high hydrostatic pressure at 400 or 600 MPa for 1 s, 2 min, 4 min, or 6 min at a process temperature of 12±2 °C. Heat injury consisted of treatment of a culture of mixed L. monocytogenes strains at 60±1 °C for 3, 6, or 9 min. Growth media were tryptic soy agar (TSA) with 0.6% yeast extract, modified Oxford medium (MOX), and TAL, which consisted of a 7-ml layer of TSA overlaid onto solidified MOX. Counts of viable L. monocytogenes on TAL were higher than those on MOX in the heat-injury experiment but not in the pressure-injury experiment. Therefore, the effectiveness of the TAL method may be specific to the type of injury applied to the microorganism and should be investigated in a variety of cellular injury scenarios.

Investigating the control of Listeria monocytogenes on alternatively-cured frankfurters using natural antimicrobial ingredients or post-lethality interventions.

The objective of this study was to investigate natural antimicrobials including cranberry powder, dried vinegar and lemon juice/vinegar concentrate, and post-lethality interventions (lauric arginate, octanoic acid, thermal treatment and high hydrostatic pressure) for the control of Listeria monocytogenes on alternatively-cured frankfurters. Lauric arginate, octanoic acid, and high hydrostatic pressure (400 MPa) reduced L. monocytogenes populations by 2.28, 2.03, and 1.88 log 10 CFU per g compared to the control. L. monocytogenes grew in all post-lethality intervention treatments, except after a 600 MPa high hydrostatic pressure treatment for 4 min. Cranberry powder did not inhibit the growth of L. monocytogenes, while a dried vinegar and a vinegar/lemon juice concentrate did. This study demonstrated the bactericidal properties of high hydrostatic pressure, octanoic acid and lauric arginate, and the bacteriostatic potential of natural antimicrobial ingredients such as dried vinegar and vinegar/lemon juice concentrate against L. monocytogenes.

Fresh meat packaging: consumer acceptance of modified atmosphere packaging including carbon monoxide.

Consumers' perceptions and evaluations of meat quality attributes such as color and shelf life influence purchasing decisions, and these product attributes can be affected by the type of fresh meat packaging system. Modified atmosphere packaging (MAP) extends the shelf life of fresh meat and, with the inclusion of carbon monoxide (CO-MAP), achieves significant color stabilization. The objective of this study was to assess whether consumers would accept specific packaging technologies and what value consumers place on ground beef packaged under various atmospheres when their choices involved the attributes of color and shelf life. The study used nonhypothetical consumer choice experiments to determine the premiums that consumers are willing to pay for extended shelf life resulting from MAP and for the "cherry red" color in meat resulting from CO-MAP. The experimental design allowed determination of whether consumers would discount foods with MAP or CO-MAP when (i) they are given more detailed information about the technologies and (ii) they have different levels of individual knowledge and media exposure. The empirical analysis was conducted using multinomial logit models. Results indicate that consumers prefer an extension of shelf life as long as the applied technology is known and understood. Consumers had clear preferences for brighter (aerobic and CO) red color and were willing to pay $0.16/lb ($0.35/kg) for each level of change to the preferred color. More information on MAP for extending the shelf life and on CO-MAP for stabilizing color decreased consumers' willingness to pay. An increase in personal knowledge and media exposure influenced acceptance of CO-MAP negatively. The results provide quantitative measures of how packaging affects consumers' acceptance and willingness to pay for products. Such information can benefit food producers and retailers who make decisions about investing in new packaging methods.

Control of Campylobacter jejuni in chicken breast meat by irradiation combined with modified atmosphere packaging including carbon monoxide.

Campylobacter is one of the leading causes of human foodborne illnesses originating from meat and poultry products. Cross-contamination of this organism occurs in many poultry processing plants, and can occur in the kitchens and refrigerators of consumers. Therefore, new intervention strategies are needed for meat and poultry products to better protect consumers from this pathogen. Vacuum or modified atmosphere packaging is a common packaging technique used by the meat and poultry industry to extend the shelf life of meat products. In addition, irradiation has been well established as an antibacterial treatment to reduce pathogens on meat and poultry products. Irradiation in combination with high-CO(2) + CO modified atmosphere packaging (MAP) was investigated in this study for the control of Campylobacter jejuni in chicken breast meat. The radiation sensitivity (D(10)-value) of this foodborne pathogen in chicken breast meat was similar in vacuum or high-O(2) MAP (0.31 ± 0.01 kGy in vacuum packaging and 0.29 ± 0.03 kGy in MAP). C. jejuni survived in both vacuum and high-CO(2) MAP through 6 weeks of refrigerated storage. Irradiation was effective for eliminating C. jejuni from meat or poultry packaged in vacuum or MAP, and should reduce the chance of cross-contamination in retail stores or home kitchens. However, irradiated off-odor and sour aroma were observed for raw, irradiated chicken breast packaged with either vacuum or MAP. Therefore, additional means to mitigate quality changes appear necessary for these products.

Survey of naturally and conventionally cured commercial frankfurters, ham, and bacon for physio-chemical characteristics that affect bacterial growth.

Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products.