Luis Manuel Medina

Transport cages used for live poultry constitute a major source of cross-contamination in slaughterhouses, particularly regarding Salmonella spp. The aim of this study was to evaluate the improvement of washing parameters—specifically temperature and detergent conductivity—in reducing Salmonella contamination as well other microbial parameters in turkey transport cages under industrial conditions. Six washing conditions were tested by combining three temperatures (40, 45, and 60 °C) and different detergent conductivities (0–4 mS/cm), using an alkaline chlorinated detergent. Microbiological analyses included Salmonella spp. and indicators such as mesophilic aerobic bacteria and Enterobacteriaceae, assessed before and after washing at three time points during the processing day. High initial contamination levels were observed in all cases. Results demonstrated a clear synergistic effect between temperature and detergent conductivity. The treatment at 60 °C and 2 mS/cm provided the most effective balance, achieving total elimination of Salmonella and significant reductions in indicator microorganisms without the need for maximum detergent concentration. Increasing conductivity beyond this level did not lead to substantial improvements. These findings support the optimization of washing parameters as a key prerequisite program within HACCP systems in poultry slaughterhouses.

This study explores tomato agri-food residues as sources of bacteria with bioprotective potential to enhance product shelf-life and safety. A total of 245 bacterial strains were isolated, comprising predominantly Pseudomonas (52%) and Bacillus (44%) spp., with lactic acid bacteria (LAB) present at lower levels (4%). The antimicrobial activity of these isolates was assessed against pathogenic and spoilage bacteria and phytopathogenic molds. Notably, the Bacillus isolate TRB1-7 exhibited moderate activity against L. monocytogenes (inhibition halo diameter: 10.64 mm), while Pseudomonas and LAB isolates showed limited or no inhibition. Antifungal assays highlighted significant antifungal potential for Bacillus isolates. Results showed that 16% and 15% of the 245 isolates inhibited F. oxysporum and C. acutatum growth, respectively. Nine of these isolates underwent acid-adaptation and were evaluated against the selected molds using Potato Dextrose Agar (PDA) at pH 4.0 to simulate tomato conditions. Only isolate BRZ3-2, identified as B. aerius, was adapted to acidic conditions and inhibited F. oxysporum by 25%. Experiments on tomato-based agar at the same pH showed no inhibition by Bacillus isolates. These results suggest that tomato microbiota harbors acid-tolerant Bacillus strains with potential for post-harvest bio-preservation. Further studies on strains TRB1-7 and BRZ3-2 are required to develop effective bioprotective applications.

For thousands of years, lactic acid bacteria (LAB) have been involved in food processes that have given rise to a wide range of traditional foods, mainly fermented foods

Milk supplied to neonates in neonatal units is kept at room temperature for some time, which could influence microbial growth. This study aims to evaluate the growth of Escherichia coli in HM and PIF under various treatments and conditions, as well as to determine the influence of different thawing methods on microbial growth in HM. The number of E. coli generations appearing over a 4 h period at 22 °C in HM (frozen; frozen and pasteurized; and frozen, pasteurized, and fortified) and in PIF (four brands) was determined. E. coli counts in HM inoculated and thawed using different methods were also compared. In frozen HM and in pasteurized and frozen HM, significant differences were found after 2.5 h and 1.5 h, respectively. In PIF, differences were found between 1.5 and 3 h. With regard to the thawing process, the lowest microorganism counts were obtained at 4 °C overnight; thus, it seems advisable to store milk at room temperature for a maximum of 1 h during administration in neonatal units. Thawing HM at 4 °C overnight should be the method of choice.

The objective of this work was to molecularly and genotypically characterize and test the inhibitory activity of six colicinogenic Escherichia coli strains (ColEc) and their partially purified colicins against STEC O157:H7 isolated from clinical human cases. Inhibition tests demonstrated the activity of these strains and their colicins against STEC O157:H7. By PCR it was possible to detect colicins Ia, E7, and B and microcins M, H47, C7, and J25. By genome sequencing of two selected ColEc strains, it was possible to identify additional colicins such as E1 and Ib. No genes coding for stx1 and stx2 were detected after analyzing the genome sequence. The inhibitory activity of ColEc against STEC O157:H7 used as an indicator showed that colicins are potent growth inhibitors of E. coli O157:H7, being a potential alternative to reduce the presence of pathogens of public health relevance.

The objective of this work was to test different treatments based on the temperature and acidification of scalding tank water throughout the day in a turkey slaughterhouse under industrial conditions in order to decrease the occurrence of Salmonella. After controlling the scalding tank water under usual conditions, the following measures were taken: (a) the temperature was increased to 60 °C and 70 °C for 15 min at the halfway point of the day; (b) the scalding water was acidified and six different initial pH levels were tested. Both measures which were tested (heating and acidification of scalding water) showed efficiency in reducing the occurrence of Salmonella during the scalding step. In order to prevent the disadvantages associated with the hardest measures in each case, we propose that scalding water be heated to 70 °C for 15 min without carcasses, which can be repeated if the disadvantages of the exposed costs and resources of processing are acceptable. Regarding acidification, a suitable measure would be an initial pH of 4.0 or any treatment that keeps the pH of the scalding water below 4.5, using acid that does not affect the final quality of the products and/or the elements involved.

Recently, the interest of consumers regarding artisan cheeses worldwide has increased. The ability of different autochthonous and characterized lactic acid bacteria (LAB) to produce aromas and the identification of the volatile organic compounds (VOCs) responsible for flavor in cheeses are important aspects to consider when selecting strains with optimal aromatic properties, resulting in the diversification of cheese products. The objective of this work is to determine the relationship between VOCs and microorganisms isolated (Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, Leuconostoc mesenteroides and Lactococcus lactis subsp. hordniae) from raw sheep milk cheeses (matured and creamy natural) using accuracy and alternative methods. On combining Sanger sequencing for LAB identification with Gas Chromatography coupled to Ion Mobility Spectrometry (GC–IMS) to determinate VOCs, we describe cheeses and differentiate the potential role of each microorganism in their volatilome. The contribution of each LAB can be described according to their different VOC profile. Differences between LAB behavior in each cheese are shown, especially between LAB involved in creamy cheeses. Only L. lactis subsp. hordniae and L. mesenteroides show the same VOC profile in de Man Rogosa and Sharpe (MRS) cultures, but for different cheeses, and show two differences in VOC production in skim milk cultures. The occurrence of Lactococcus lactis subsp. hordniae from cheese is reported for first time.

In this study, the possible influence of the food matrix and the interfering population of microorganisms on the detection and count of Listeria monocytogenes in three common foods of the Spanish diet (Spanish omelette, fresh cheese and vegetable salad) was determined. Four groups were assayed: one control, two groups with interfering microorganisms (Salmonella Enteritidis, Staphylococcus aureus and Proteus mirabilis) with different levels of L. monocytogenes and a final group only contaminated with L. monocytogenes. The samples were analyzed with the normalized method (UNE-EN ISO 11290:2018) and with an alternative technique (VIDAS). The results show that the presence of interfering microorganisms did not seem to interfere with the determination of L. monocytogenes. Furthermore, the type of food did not seem to influence the determination of L. monocytogenes, but the culture media used showed differences. In fact, regardless of the type of food, the ALOA medium showed higher sensitivity than the other media, with higher recovery in 100% of samples (only for the Spanish omelette in Group B was the result the same as that for PALCAM, −8.11 log cfu/g). The results obtained using the VIDAS were not influenced by any of the factors or conditions used and show 100% efficiency.

The objective of this study was to evaluate a series of measures aimed at reducing the occurrence of Salmonella in turkeys bred in Spain, during all the stages prior to the slaughterhouse stage.The following measures were evaluated: (a) control in feed production; B) cleaning and disinfection of farms (by thermo-fogging or spraying, using three disinfectants); c) treatment of litter using Ca(OH)2; d) treatment of drinking water with an acidifying mixture based on formic acid, orthophosphoric acid and propionic acid; and (e) cleaning and disinfection of boxes, cages and vehicles.All the measures tested proved to be effective, especially the control of feed production and the treatments for cleaning and disinfecting farms, boxes, cages and vehicles, which resulted in the absence of Salmonella in all the samples tested. In the case of disinfectants 3 and 4, the results were not statistically significant. Treatment of the litter reduced the percentage presence of Salmonella by almost 50% on untreated rearing farms, and on fattening farms by 17.5%. In terms of the treatment of drinking water, the treatment carried out in both rearing and fattening farms decreased the occurrence of Salmonella (34.5% and 36.2%, respectively) with respect to the percentages obtained on farms prior to treatment.

La producción intensiva y extensiva de cerdo en Argentina y España respectivamente presenta factores productivos diferentes. Sin embargo, cuando se trata de amenazas ante patógenos, específicamente Salmonella, ambos se ven afectados. Salmonella es un patógeno común en los alimentos relacionado con las toxiinfecciones alimentarias que provoca graves problemas en la salud pública. Las bacterias acidolácticas, específicamente los géneros Lactobacillus y Pediococcus se han caracterizado en los últimos años por tener gran importancia como antagonistas de diferentes bacterias patógenas. Una alternativa de control es la aplicación de Lactobacillus a lo largo de la cadena productiva de cerdo, evitando así la llegada de este patógeno a los consumidores. Se realizó una evaluación preliminar de la capacidad antagónica de bacterias acidolácticas identificadas tras secuenciación como Lactobacillus plantarum y Pediococcus acidilactici ante Salmonella Tiphymurium aislada de producción intensiva de cerdo de Argentina y Salmonella Tiphymurium aislada de producción extensiva de cerdo en España. Los resultados obtenidos reflejaron una alta capacidad antimicrobiana de las BAL seleccionadas ante ambas cepas patógenas (93.75%). De esta manera, se proponen como potenciales bacterias biopreservadoras en la producción de carne de cerdo y subproductos.