Increase in temperature facilitates Campylobacter jejuni biofilm formation under both aerobic and microaerobic incubation.

The formation of Campylobacter jeuni biofilms on processing surfaces is a significant concern in poultry processing, contributing to food safety risks. This study focused on assessing the biofilm forming capabilities of 12 field isolates of C. jejuni of different aerotolerance categories on stainless steel surfaces, a prevalent material in poultry processing environments. Working cultures of each isolate were prepared to approximately 6 log CFU/mL and incubated on stainless steel coupons under microaerobic or aerobic conditions at room temperature or 42°C for 72 h. Biofilm attached cells were enumerated using direct plating and biofilm density was measured using a crystal violet assay by measuring the optical density (OD600) a. Data analysis was conducted using the PROC GLIMMIX procedure in SAS 9.4 with a significance level of 0.05. The study revealed a notable interaction between aerotolerance categories and temperature (P < 0.039) impacting the number of biofilms attached C. jejuni cells on stainless steel coupons. All isolates had significantly higher counts when incubated at 42°C compared to room temperature, regardless of oxygen level (P < 0.001). Furthermore, stronger biofilm density was observed at 42°C compared to room temperature, regardless of oxygen level. These findings underscore the influence of temperature on the biofilm forming ability of C. jejuni. The ability of these field isolates to form biofilms under various environmental conditions suggests a heightened potential for surface colonization and increased infection risk in poultry processing facilities.

Roles of Aerotolerance, Biofilm Formation, and Viable but Non-Culturable State in the Survival of Campylobacter jejuni in Poultry Processing Environments.

Campylobacter jejuni is one of the most common causes of foodborne human gastroenteritis in the developed world. This bacterium colonizes in the ceca of chickens, spreads throughout the poultry production chain, and contaminates poultry products. Despite numerous on farm intervention strategies and developments in post-harvest antimicrobial treatments, C. jejuni is frequently detected on broiler meat products. This indicates that C. jejuni is evolving over time to overcome the stresses/interventions that are present throughout poultry production and processing. The development of aerotolerance has been reported to be a major survival strategy used by C. jejuni in high oxygen environments. Recent studies have indicated that C. jejuni can enter a viable but non-culturable (VBNC) state or develop biofilm in response to environmental stressors such as refrigeration and freezing stress and aerobic stress. This review provides an overview of different stressors that C. jejuni are exposed to throughout the poultry production chain and the genotypic and phenotypic survival mechanisms, with special attention to aerotolerance, biofilm formation, and development of the VBNC state.

Microbial Indicators and Possible Focal Points of Contamination during Production and Processing of Catfish.

The catfish industry is important to the United States economy. The present study determined the levels of microbial indicators and the prevalence of Listeria spp. and Listeria monocytogenes at catfish farms and catfish processing plants. Live fish, water, and sediment samples were analyzed in farms. Fish skin, fillets, chiller water, and environmental surfaces were assessed at the processing plants both during operation and after sanitation. Live fish had 2% prevalence of Listeria monocytogenes, while sediment and water were negative for Listeria. Live fish skin counts averaged 4.2, 1.9, and 1.3 log CFU/cm2 aerobic (APC), total coliform (TCC) and generic Escherichia coli counts, respectively. Water and sediment samples averaged 4.8 and 5.8 log CFU/g APC, 1.9 and 2.3 log CFU/g TCC, and 1.0 and 1.6 log CFU/g generic E. coli counts, respectively. During operation, Listeria prevalence was higher in fillets before (57%) and after (97%) chilling than on fish skin (10%). Process chiller water had higher (p ≤ 0.05) APC, TCC, and Listeria prevalence than clean chiller water. After sanitation, most sampling points in which Listeria spp. were present had high levels of APC (>2.4 log CFU/100 cm2). APC combined with Listeria spp. could be a good approach to understand microbial contamination in catfish plants.

Bacitracin, Bacillus subtilis, and Eimeria spp. challenge exacerbates woody breast incidence and severity in broilers.

Woody breast (WB) is a myopathy that is related to the increasing growth rate. Understanding the influence of management factors on WB formation and development is important to minimize WB. This study was conducted to define how management factors affect broiler growth performance, processing yield, and WB incidence. Ross × Ross 708 chicks were randomly assigned to a 3 (diet) × 2 (cocci challenge) × 2 (sex) factorial arrangement of treatments. The 3 dietary treatments were: control diet (corn-soybean meal basal diet), antibiotic diet (basal diet + 6.075 mg bacitracin /kg feed), and probiotic diet (basal diet + 2.2 × 108 CFU Bacillus subtilis PB6/kg feed). Birds in cocci challenge treatments received 20 × live cocci vaccine on d 14. The hardness of breast muscle in live birds was determined by palpation and grouped into Normal, Slight, Moderate, and Severe categories. Across diet and sex treatments, the cocci challenge resulted in decreases in body weight (BW) on d 29 and 35 (P < 0.0001 and = 0.032) in body weight gain (BWG) from d 14 to 29 (P < 0.0001). However, an increase of BW occurred on d 35 (P = 0.032) and an increase of BWG occurred from d 29 to 35 and d 35 to 43 (P = 0.0001 and 0.002), and the cocci challenge increased WB incidence on d 29 (P = 0.043) and d 43 (P = 0.013). Across challenge and sex treatments, birds fed the antibiotic diet exhibited a higher growth rate (GR) than those fed the control or probiotic diet from d 0 to 14 (P = 0.016), but not after d 14 (P > 0.05). Across sex, the antibiotic and probiotic diets increased WB incidence for those birds that did not receive a cocci challenge on d 43 (P = 0.040). Across challenge and diet treatments, males exhibited a higher BW, BWG, and GR throughout all growth phases, and males showed a higher WB incidence on d 29, 35, and 43 (P = 0.002, P < 0.0001, and P = 0.0002, respectively). In conclusion, bacitracin and Eimeria spp. increased WB incidence, BW, and GR. However, Bacillus subtilis increased WB incidence in male broilers without affecting BW and GR.

Prevalence of Salmonella enterica on poultry processing equipment after completion of sanitization procedures.

Salmonella is a poultry-borne pathogen that causes illness throughout the world. Consequently, it is critical to control Salmonella during the process of converting broilers to poultry meat. Sanitization of a poultry processing facility, including processing equipment, is a crucial control measure that is utilized by poultry integrators. However, prevalence of Salmonella on equipment after sanitization and its potential risk to food safety has not been evaluated thoroughly. Therefore, the objective of this study was to evaluate the persistence of Salmonella on poultry processing equipment before and following cleaning and sanitization procedure. A total of 15 locations within 6 commercial processing plants were sampled at 3 time points: (A) after processing; (B) after cleaning; and (C) after sanitization, on 3 separate visits for a total of 135 samples per plant. Salmonella-positive isolates were recovered from samples using the United States Department of Agriculture MLG 4.09 conventional method. Presumptive Salmonella colonies were subjected to biochemical tests for confirmation. Salmonella isolates recovered after sanitization were serotyped and tested for the presence of specific virulence genes. A completely randomized design with a 6 × 3 × 15 factorial arrangement was utilized to analyze the results for Salmonella prevalence between processing plants. Means were separated using Fishers protected least significant difference when P ≤ 0.05. For Salmonella prevalence between processing plants, differences (P < 0.0001) were observed in the 6 plants tested where the maximum and minimum prevalence was 29.6 and 7.4%, respectively. As expected, there was a difference (P < 0.0001) in the recovery of Salmonella because of sampling time. Salmonella prevalence at time A (36%) was significantly higher, whereas there was no difference between time B (12%) and C (9%). There was a location effect (P < 0.0001) for the prevalence of Salmonella with the head puller, picker, cropper, and scalder having a significantly higher prevalence when compared with several other locations. At sampling time C, a trend toward a difference (P = 0.0899) was observed for Salmonella prevalence between the 6 plants, whereas significant differences were observed because of location (P = 0.0031). Five prominent Salmonella enterica serovars were identified, including Kentucky, Schwarzengrund, Enteritidis, Liverpool, and Typhimurium with S. Kentucky being the most prevalent. PCR analysis of 8 Salmonella virulence genes showed that the invA, sipB, spiA, sseC, and fimA were detected in all isolates, whereas genes carried on plasmids and/or fimbriae varied remarkably among all isolates. This study established Salmonella prevalence and persistence in poultry processing facilities after antimicrobial application through sanitization procedures which could result in contamination of poultry carcasses and food safety risks because of poultry meat.

Efficacy of Controlled Atmosphere Treatments to Manage Arthropod Pests of Dry-Cured Hams.

Research here explored the use of controlled atmospheres (CA) for managing arthropod pests that infest dry-cured hams. Experiments were conducted with low oxygen (O2) achieved with low pressure under a vacuum, high carbon dioxide (CO2), and ozone (O3). Results showed that both low O2 and high CO2 levels required exposures up to 144 h to kill 100% of all stages of red-legged ham beetle, Necrobia rufipes (De Geer) (Coleoptera: Cleridae) and ham mite Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) at 23 °C. In addition, both low O2 and high CO2 had no significant mortality against the ham beetle and ham mites at short exposures ranging from 12 to 48 h. Ham beetles were more tolerant than ham mites to an atmosphere of 75.1% CO2 and low pressure of 25 mm Hg, which imposed an atmosphere estimated at 0.9% O2. Both low O2 and high CO2 trials indicated that the egg stages of both species were more tolerant than other stages tested, but N. rufipes eggs and pupae were more susceptible than larvae and adults to high concentration ozone treatments. The results indicate that O3 has potential to control ham beetles and ham mites, particularly at ≈166 ppm in just a 24 h exposure period, but O3 is known from other work to have poor penetration ability, thus it may be more difficult to apply effectively than low O2 or high CO2. would be. CA treatment for arthropod pests of dry-cured hams show promise as components of integrated pest management programs after methyl bromide is no longer available for use.

The combined efficacy of carvacrol and modified atmosphere packaging on the survival of Salmonella, Campylobacter jejuni and lactic acid bacteria on turkey breast cutlets.

The primary objective of this study was to determine the efficacy of carvacrol in combination with modified atmosphere packaging (MAP) in reducing Salmonella on turkey breast cutlets stored at 4 °C. In experiment I, carvacrol (0.5, 1, and 2% v/v) was applied as surface treatment and samples were stored under aerobic condition or as surface and dip treatments followed by storage in an environment of 100% carbon dioxide. The findings of the experiment I revealed the synergistic activity of carvacrol with carbon dioxide in reducing Salmonella when used as dip treatment compared to the surface treatment. In experiment II, turkey breast cutlets were dip treated with carvacrol (0.25, 0.5, and 1% v/v) for 30 s and stored under MAP (95% carbon dioxide and 5% oxygen) to evaluate the efficacy against Salmonella, Campylobacter jejuni and lactic acid bacteria on turkey breast cutlets. In experiment II, the combined application of carvacrol and MAP resulted in 1.0-2.0 log CFU/g reduction (P ≤ 0.05) of both Salmonella and Campylobacter on turkey breast cutlets for 7 d storage at 4 °C. MAP alone and in combination with carvacrol reduced lactic acid bacteria (P ≤ 0.05) on cutlets stored at 4 °C for 21 d period. There was no difference (P ≤ 0.05) in meat color among treatments and controls except for an increased paleness of meat (P ≤ 0.05) observed for the 1% carvacrol treated cutlets stored under MAP after 21 d of storage. The high concentration of carbon dioxide and carvacrol treatments did not cause any alteration in meat pH (P ≤ 0.05). In conclusion, carvacrol was effective at a low concentration of 0.25% (v/v) in reducing Salmonella and C. jejuni by ∼1.0 log CFU/g when stored under MAP.

Reduction of Salmonella on turkey breast cutlets by plant-derived compounds.

The foodborne illnesses associated with poultry meat due to Salmonella are a major concern in the United States. In this study, the antimicrobial efficacy of carvacrol, eugenol, thyme essential oil, and trans-cinnamaldehyde was determined against different Salmonella serotypes in vitro and on turkey breast cutlets. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of antimicrobial agents were determined using a microdilution colorimetric assay. Carvacrol was the most effective antimicrobial agent since it exhibited the lowest MIC and MBC (0.313 µL/mL, respectively) in culture media against Salmonella. Turkey breast cutlets inoculated with Salmonella Enteritidis, Salmonella Heidelberg, and Salmonella Typhimurium were dip treated with different concentrations (0.5, 1, 2, and 5% vol/vol) of carvacrol, eugenol, thyme essential oil, and trans-cinnamaldehyde for 2 min. Samples were analyzed after 24-h storage at 4°C for recovery of Salmonella. Significant reductions of Salmonella (p≤0.05) on turkey breast cutlets were obtained with 1, 2, and 5% treatments. These compounds exhibited a concentration-dependent response on turkey breast cutlets against Salmonella. For example, 1% carvacrol resulted in 1.0 log colony-forming units (CFU)/g reduction of Salmonella whereas 5% carvacrol caused 2.6 log CFU/g reduction. Based on its efficacy in the 2-min dip study, carvacrol was selected for 30-s and 60-s dip treatments of Salmonella-inoculated turkey breast cutlets. Dipping turkey breast cutlets in 5% carvacrol for 30 s and 60 s resulted in 1.0 and 1.8 log reductions of Salmonella (p≤0.05), respectively. None of the antimicrobial agents caused any changes in the meat pH (p>0.05). In conclusion, this study revealed that plant-derived compounds such as carvacrol can reduce Salmonella on turkey breast cutlets without changing the pH of meat.

Low, medium, and high heat tolerant strains of Listeria monocytogenes and increased heat stress resistance after exposure to sublethal heat.

A group of 37 strains representing all 13 serotypes of Listeria monocytogenes with an initial cell density of 10(7) CFU/ml were analyzed for their heat tolerance at 60°C for 10 min. These L. monocytogenes strains were categorized into three heat tolerance groups: low (<2 log CFU/ml survival), medium (2 to 4 log CFU/ml survival), and high (4 to 6 log CFU/ml survival). Serotype 1/2a strains had relatively low heat tolerance; seven of the eight tested strains were classified as low heat tolerant. Of the two serotype 1/2b strains tested, one was very heat sensitive (not detectable) and the other was very heat resistant (5.4 log CFU/ml survival). Among the 16 serotype 4b strains, survival ranged from not detectable to 4 log CFU/ml. When one L. monocytogenes strain from each heat tolerance group was subjected to sublethal heat stress at 48°C for 30 or 60 min, the survival of heat-stressed cells at 60°C for 10 min increased by 5 log CFU/ml (D60°C-values nearly doubled) compared with the nonstressed control cells. Sublethal heat stress at 48°C for 60 or 90 min increased the lag phase of L. monocytogenes in tryptic soy broth supplemented with 0.6% yeast extract at room temperature by 3 to 5 h compared with nonstressed control cells. The heat stress adaptation in L. monocytogenes was reversed after 2 h at room temperature but was maintained for up to 24 h at 4°C. Our results indicate a high diversity in heat tolerance among strains of L. monocytogenes, and once acquired this heat stress adaptation persists after cooling, which should be taken into account while conducting risk analyses for this pathogen.