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The 2021 FSIS Appendix B guidelines restrict cooling of meat and poultry products to limit the growth of Clostridium perfringens to no greater than 1-log. This study compared the effect of pH and salt on the growth of 3 sporeforming pathogens, Clostridium perfringens, Bacillus cereus, and Clostridium botulinum during extended cooling in an uncured poultry product. Nine turkey treatments (75% moisture) were formulated using a full factorial design (pH 5.8, 6.2, 6.6; salt 1.2%, 1.5%, 1.8%). Treatments were inoculated with 3-log spores/g of C. perfringens, B. cereus, or C. botulinum and vacuum-packaged (25 g/package). Samples were cooked to 73°C, then cooled from 48.9 °C to 26.7 °C (phase 1) in 1, 1.5, 2, 2.5, or 3 h, from 26.7 °C to 12.8°C (phase 2) and from 12.8°C to 4.4°C (phase 3) in 5 h each. Samples were assayed by enumerating on selective agars at 0-time (post cook before incubation) and at internal temperatures 48.9, 26.7, and 4.4 C. C. botulinum grew < 1-log, and no botulinum toxin was detected regardless of cooling rate or formulation tested. B. cereus was inhibited in all formulations through the 12.5 h total cool (2.5-h phase 1 cooling), but > 1-log increase was observed in pH 6.6 formulations for 13-h total cool. Less than a 1-log C. perfringens growth was detected for all treatments when phase 1 cooling was limited to 1 h, with 1.5-h phase 1 cool for pH < 6.2 with > 1.2% salt, pH 6.6 with > 1.5% salt, and 2-h phase 1 cool for pH < 5.8 and 1.8% salt. All formulations supported a 1- to 3-log increase of C. perfringens when phase 1 cool was 3 h. This study confirms cooling conditions that inhibit C. perfringens will likewise inhibit C. botulinum and B. cereus for the duration of the cooling, and phase 1 cooling can be extended up to 2.5 h depending on salt/pH combinations.

The purpose of this study was to investigate changes in the microbial community structure consisting of spoilage lactic acid bacteria (LAB) when sodium lactate (SL) and SL + sodium diacetate (SD) are included in RTE meat product formulations at concentrations commonly used for controlling Listeria monocytogenes. Sliced cooked, vacuum-packaged turkey breast samples containing no SD or SL (control [C]), 0.125% SD, and the combination of 2.5% SL + 0.125%SD (SLSD) were inoculated with a target of 3 log colony-forming units (CFU)/g of 5 different LAB species (Lactobacillus sakei, Leuconostoc mesenteroides [bacon and deli-shaved ham isolates], Lactococcus lactis, and Enterococcus faecium) and stored at 4°C for 35 d. Microbial community changes were analyzed utilizing 16S ribosomal RNA (rRNA) gene sequencing for the V4 region from the samples collected at days 0, 7, 14, 21, and 35. No significant difference (P>0.05) was observed between the richness of microbial community for all treatments. According to Bray-Curtis dissimilarity matrix and permutational analysis of variance, a significant difference in β-diversity was observed only between C and SLSD (P0.05) was observed for the SD treatment compared with C in the microbiota. According to the results from this study, only SLSD affected the microbial community structure at the beginning of the storage. This study demonstrated that the incorporation of SL in the formulation slowed down the microbial spoilage and the changes in the microbiota of RTE meat products.

This study investigated the effectiveness of cooking processes that incorporated hydrated surface lethality (HSL) steps for ensuring the reduction of Salmonella on the surfaces of small-dimension meat and poultry products cooked using short-duration, high-temperature impingement oven processes. Whole-muscle chicken tenders (3% fat), beef patties (10% and 30% fat), pork patties (10% and 30% fat), and chicken patties (10% and 20% fat) were surface inoculated with a 5-strain mixture of Salmonella to yield 8 log colony-forming units/g, then cooked in a two-zone impingement oven using either dry heat or steam-humidified HSL processes. The HSL steps used steam injection to control the wet-bulb temperature at either 71.1°C or 82.2°C. Dry-heat cooking processes using a dry-bulb temperature of 204.4°C and no steam-injected HSL steps failed to consistently achieve a 6.5 log reduction of Salmonella on chicken tenders and the low-fat patty products (≤10% fat). In contrast, processes incorporating an HSL step using an 82.2°C wet-bulb temperature in one or both zones resulted in ≥6.5 log reductions of Salmonella for all products. Sufficient reductions were achieved regardless of whether this 82.2°C wet-bulb HSL step was incorporated before or after a dry-cook step. Processes that incorporated an HSL step using a 71.1°C wet-bulb temperature in both zones also resulted in reductions ≥6.5 log for all products. Processes using a 71.1°C wet-bulb HSL step in only one zone delivered ≥ 6.5 log reduction for all of the patty products. However, the one-zone 71.1°C HSL step achieved ≥6.5 log reduction in chicken tenders only if used in the first zone of the two-zone oven. When the 71.1°C HSL step was used in the second zone for chicken tenders after using dry heat in the first zone, the target reduction of 6.5 log was not achieved. This research successfully validated approaches to ensure ≥6.5 log reduction of Salmonella on product surfaces.

Salt is a critical ingredient in processed meat and poultry products because of its multiple functions that affect product quality and safety. Although salt is a functional ingredient in food products, sodium reduction continues to be an important topic within the food industry due to interests in reducing dietary sodium intake. Previous work has shown that soy sauce addition may potentiate saltiness perception in processed meats and thus allow for novel formulations with reduced sodium content. Two studies were conducted to further elucidate these effects. First, trained panel sensory char- acteristics, relevant quality parameters, and selected chemical profiles were determined comparing frankfurters containing flake salt and traditionally brewed soy sauce. Seven aqueous compounds were found to be more abundant (P < 0.001) in the soy sauce – containing treatment, and 56 volatile compounds were identified. Principal component analysis of the sensory and selected chemical profiles led to the consideration that ethyl hexanoate (EHEX) may be a causative agent of the saltiness-potentiating phenomenon. Thus, a second study further evaluated concentrations of EHEX, revealing that trained sensory panelists perceived frankfurters containing EHEX as saltier (P < 0.05) and these frankfurters had higher scores for fermented/sour aromatic score (P < 0.05) than the control (Control: 100% NaCl from flake salt). This research demon- strated the ability of EHEX to potentiate saltiness in frankfurters with minimal effects on quality.