U.S. National Poultry Research Center

Consumption of poultry products continues to rise in the United States, highlighting the importance of mitigating foodborne pathogens during poultry processing. Developing new methodologies to improve the detection of pathogens within processing plants is essential to protect food safety. Growing demand for a more representative sample and desire to improve bacterial detection at low levels have led to the evaluation of new sample collection tools. Our objective was to evaluate one such tool, the MicroTally® Mitt, a polymer fabric that has shown improved microbial recovery in beef trim and turkey carcasses, by comparing it to the traditional carcass or parts rinse method for detecting total aerobic microorganisms (rapid aerobic count; RAC), Enterobacteriaceae (EB), Campylobacter, and Salmonella before and after antimicrobial interventions. Additionally, the mitt was tested for its utility in collecting a composite sample (multi-carcass mitt). Three commercial broiler processing establishments were visited twice. Whole carcass samples were collected at hot rehang (n=150) and post-chill (n=150). Wing samples were collected before and after antimicrobial application (n=136 and n=147, respectively). A total of 233 whole carcass rinses (WCRs), 233 single-carcass mitts (SC-mitts), and 117 multi-carcass mitts (MC-mitts) were collected. As expected, recovery was greatest at hot rehang for all microbial counts (RAC, EB, Campylobacter, and Salmonella) and lowest post-chill. Deep serotyping of Salmonella culture-positive samples (n=100) from hot rehang showed multiple serovars were detected in 53% (20/38) WCR, 58% (22/38) single-carcass mitt, and 50% (12/24) of multi-carcass mitt samples. For all microbial counts, the single-carcass mitt had comparable bacterial recovery to rinses in hot rehang samples. Low bacterial recovery following antimicrobial interventions prevented further sample type comparisons at other processing stages but showed processing intervention efficacy.

Eggs are an important trade commodity around the world. However, how eggs are handled/processed and stored differ by country. In the United States, under federal and state regulations, eggs are washed and stored at refrigerated temperatures. These practices can be an obstacle if the eggs are destined for export markets. The focus of this study was to assess the impact of egg handling practices and storage temperature on egg quality during a 27-week storage period. Conventional commercial white shell eggs were obtained and handled under four treatments: 1) unwashed (U) 2) washed (W; USDA-Agricultural Marketing Service (AMS) guidelines), 3) washed and oiled (O; food-grade mineral oil; AMS guidelines), and 4) 21 days refrigerated storage (AMS guidelines) then washed (21 W). All egg handling occurred at a commercial facility. The eggs were then transported to the US National Poultry Research Center in Athens, GA. Three cases of eggs from each egg handling treatment were stored in either refrigeration (R; 4 °C) or room temperature (A; 22 °C). To determine egg weight loss throughout the study, 30 eggs were randomly selected from each treatment/replicate combination and grouped according to storage temperature. These eggs were then weighed each week to determine egg weight loss throughout the 27 weeks of storage. At Weeks 0, 1, 2, 3, 4, 6, 8, 10, 12, 14, 18, 22, and 27, ten eggs were randomly selected from each replicate of egg handling treatment and storage temperature combinations and assessed for various physical egg quality parameters. The greatest decreases in egg weight were observed in eggs at 22 °C: A-U, A-W, and A-21 W (P < 0.0001). A-O eggs had comparable egg weight loss to eggs stored at 4 °C. Storage temperature had a profound impact on Haugh units. After one week of storage at 22 °C (P < 0.0001), A-W, A-21 W, and A-U eggs had dropped to USDA-AMS Grade B. A-O eggs were able to maintain Grade A through 4 weeks of storage (P < 0.0001). Haugh unit measurements for 22 °C stored eggs were only possible until 8 weeks of storage. R-O and R-U eggs were able to maintain Grade A Haugh unit scores (P < 0.05) through 27 weeks of 4 °C storage. R-W and R-21 W eggs retained Grade A Haugh unit scores through 18 weeks (P < 0.05). This study shows the importance of storage temperature on preserving egg quality over extended storage.

Drought increasingly challenges rainfed maize (Zea mays L.) production worldwide, with pressures expected to intensify under future climate scenarios. Recent studies have examined the genetic and physiological bases of yield and drought tolerance improvements in maize; however, comprehensive, field-based quantification of synchronous improvements of yield and drought resistance across diverse environmental conditions remain limited. By compiling a dataset of 92,096 hybrid-trial observations across the U.S. Corn Belt (2000–2020), our environmental index approach provides evidence of consistent yield increases across diverse environmental conditions. Using linear mixed-effects modeling, we reveal these gains are accompanied by enhanced drought resistance during the grain filling period. Projections suggest that by 2100, new hybrids could transform drought resistance, reducing yield losses by 17.8% compared to old hybrids, suggesting the potential of breeding innovations to buffer maize against drought stress. This study highlights recent breeding efforts, reinforcing adaptative capacity of maize and providing a promising pathway to sustain food security in a warming climate.

Laboratory-confirmed infections with H5N1 and H7N9 As per World Health Organization (WHO) reporting of human infections with H5 and H7 avian influenza viruses [2-4], Luczo and Spackman [5] reported laboratory-confirmed H7N9 (and H5N1) infections and the associated (laboratory-confirmed) case fatality rate. The cumulative number of human cases for H5N1 reported to WHO 2003-2025 also includes (laboratory-confirmed) reported detections in asymptomatic individuals. We have not misinterpreted the (laboratory-confirmed) H7N9 or H5N1 case fatality rate and have clearly defined that the metric reported is related to laboratory-confirmed infections. Notably, both the WHO and experts in the field continue to report this metric based on laboratory-confirmed infections. Pathogenicity of non-H5/H7 avian influenza viruses We don't believe that the statement “Experimental studies have shown that other subtypes like H2, H4, H6, H8, H9, and H14 can support a highly pathogenic phenotype” is at disharmony with non-H5/H7 subtypes having low pathogenic phenotypes in nature. Furthermore, in Luczo and Spackman [5], we describe that low pathogenicity avian influenza viruses generally cause non-clinical or mild disease compared to highly pathogenic avian influenza. Regardless, the pathobiology of low pathogenic avian influenza was not a primary focus of this work and has been reviewed elsewhere [6, 7]. However, to try to address Ghaemi et al. [1] concerns, first it is unclear whether Ghaemi et al. are referring to the World Organization for Animal Health (WOAH) regulatory definition of highly pathogenic avian influenza and low pathogenic avian influenza [8] or a more general clinical description of disease. Regardless, the severity of low pathogenic avian influenza pathogenesis is subjective and for poultry production even “mild” clinical disease [9] can result in substantial economic losses in the field due to decreased production. Low pathogenic avian influenza virus isolates of almost all subtypes have been reported to cause notable disease in the field [10-14] which has warranted the cost to implement control measures. Therefore, a broader view of the disease impact of low pathogenic avian influenza is not inappropriate regardless of how it is presented in Luczo and Spackman [5]. In the context of the WOAH definition, Luczo and Spackman [5] describe that highly pathogenic viruses have evolved naturally in the H5 an H7 subtypes only. However, there are several studies of interest with recombinant and wild type viruses that provide insights as to the complexity of influenza pathogenicity. For example, there is clear evidence that in experimental settings some non-H5/H7 subtypes have the potential to support a highly pathogenic phenotype [15-18]. Ghaemi et al. [1] also conclude that experimental changes can transform non-H5/H7 into highly pathogenic phenotype, making their argument on this a moot point. Of interest is why only H5 and H7 avian influenza viruses naturally convert to highly pathogenic forms – knowledge of this could be harnessed to mitigate the genesis of these highly pathogenic viruses. Additionally, it has been reported that a wild type H10 virus that has a low pathogenicity cleavage site has an intravenous pathogenicity index of 1.76, which meets the WOAH definition for a highly pathogenic avian influenza virus [19]. Finally, despite being classified as of low pathogenicity, H9 avian influenza viruses pose a significant threat to the poultry industry and it has been noted that infection of chickens with some H9N2 virus lineages cause severe disease and even death in poultry [20-25]. We also wish to clarify that H9 avian influenza viruses are not present in poultry globally – it is not enzootic in the Americas, Europe, nor Australia, for example. Collectively, whilst non-H5/H7 viruses are classified as low pathogenicity, there is clear evidence that some non-H5/H7 viruses do not follow this trend. Writing – original draft: J.M.L. Writing – review and editing, J.M.L. and E.S. The authors declare no conflicts of interest.

Herpesviruses have evolved numerous immune evasion tactics, persisting within their hosts through self-perpetuating strategies. One such tactic involves acquiring functional copies of host genes encoding cytokines such as IL-6 (HHV-8), IL-10 (HHV-4, HHV-5), and IL-17 (SaHV-2). These viral mimics, or virokines, can bind to cellular receptors, modulating the natural cytokine signaling to manipulate the immune response in favor of the virus or stimulate target cell growth to enhance virus replication. In the course of full-length cDNA sequencing of infectious laryngotracheitis virus (ILTV) transcripts, a previously unknown highly spliced gene was discovered in the viral genome predicted to encode a 147 amino acid protein with similarity to vertebrate interleukin-4. The three-intron gene structure was precisely conserved with chicken and other vertebrate IL-4 homologs, and the amino acid sequence displayed structural conservation with vertebrate homologs at the primary, secondary, and tertiary levels based on computational modeling. The viral IL-4 gene was subsequently identified in all sequenced ILTV genomes. The mature transcript was highly expressed both in vitro and in vivo, and protein expression in infected cells was confirmed using LC-MS/MS. Phylogenetic analyses, along with the conserved gene structure, suggested direct capture from a Galliformes host. Functionally, an LPS-stimulation assay showed that the expressed viral IL-4 homolog stimulated nitric oxide production in a macrophage cell line at comparable levels to recombinant chicken IL-4. A recombinant virus lacking vIL-4 exhibited slightly higher titers in cell culture compared to the parental strain. In vivo bird studies demonstrated reduced pathogenicity of the vIL-4 knockout compared to wildtype. These results represent the first report of a previously unknown virokine encoded in the ILTV genome expressing a functional IL-4 homolog and virulence factor.

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