Effect of Scalding Temperature on Growth of Staphylococcus aureus and Formation of Staphylococcal Enterotoxin during the Production of Alpine Cheese in a Laboratory Cheesemaking Model

Abstract

To reduce the number of potential S. aureus contaminated cheese reaching consumers, European legislation stipulates that all cheese must be tested for coagulase-positive staphylococci (CPS) at the point in production when numbers are expected to be highest. If CPS counts exceed 105 CFU/mL, enterotoxin tests must be conducted. In the case the enterotoxin test shows positive results the cheese must be destroyed. Manufacturers of Swiss Alpine cheese are exempt from this legislation because enterotoxin formation in hard cheese is expected to be very unlikely, given the high scalding temperatures the cheese is exposed to during its production. Such temperatures result in inactivation of CPS in the curd. However, this assumption has not yet been scientifically demonstrated. Therefore, a laboratory-scale cheese production experiment was performed, in which the conditions corresponded with certain limitations to practical cheese-making conditions in terms of temperature and time exposure like in Gruyere or Tete de Moine Swiss type cheese. Raw milk aliquots (200 ml) were inoculated with five different strains of CPS, and scalding temperatures, ranging from 46–56° C, were applied during cheese production. The temperatures applied after pressing the curd aimed at reproducing the temperature curve in the peripheral zone of a real cheese wheel. Contrary to expectations, enterotoxin formation occurred and changed with the different scalding temperatures (52–56° C).The differences in enterotoxin formation were more associated with strain type rather than temperature. Based on these results, the mechanism of enterotoxin formation in cheese requires further study.

The Enterotoxin Gene Profiles and Enterotoxin Production of Staphylococcus aureus Strains Isolated from Artisanal Cheeses in Belgium

“…In 16.7% of the varieties of Belgian cheese made from raw milk, we found strains possessing an seg truncated gene (segT) (Table 2) with a predicted protein of 191 amino acids (SEGT), which exhibited an SEG that was truncated in the C terminal relative to a non-truncated SEG. Strains with similar gene profiles were previously classified by their vSaβ type and characterized as being low or high producers of SEI and SEG [44]. SEGT was not detected via ELISA, but LC-MS detected SEGT in 33.3% of strains possessing segT (Table 2).…”

“…Among the genes coding for non-classic enterotoxins, six genes (seg, sei, sem, sen, seo and selu) are located on the egc cluster, which is part of the S. aureus genomic island vSaβ [43]. The genomic analysis of the strain allowed the identification of the origin (food poisoning outbreak, human carrier, animal carrier) and the type of contamination and can be used to predict the production of SEs [44]. The occurrence of SE(l) genes, and specifically egc genes, in S. aureus isolated from food is highly variable, which may be mainly related to the geographical and/or food type origin of isolates and to the methods used for their detection [4,12,45].…”

Determinación de Staphylococcus aureus en quesos frescos del mercado 9 de octubre de la ciudad de Cuenca, Agosto 2023.

“…Se clasifica como un coco Gram positivo, en forma de racimos de uvas, no móvil, anaerobio facultativo, tiene una temperatura máxima de 37 °C, producen un pigmento amarillo dorado y son halotolerantes, las https://doi.org/10.55204/trc.v4i1.e295 toxinas que produce son: Hemolisina, Toxina Panton-Valentine (PVL), Toxinas exfoliativas o epidermolíticas, La toxina 1 del síndrome del choque tóxico (TSST-1). Está presente en el agua, aire y alimentos especialmente en los lácteos y embutidos (12,13,14,15).…”

Effects of Gouda cheese and Allium hookeri on thermogenesis in mice

“…The beneficial effects of this herb are attributed to the presence of various phenols (e.g., ferulic acid, gallic acid, and cinnamic acid), phytosterols, linoleic acid, and organosulfur compounds. Allium hookeri is known to have bioactive properties, such as antioxidant (Cho et al., 2015; Kim et al., 2016), antimicrobial (Lucchini et al., 2018; Poznanski et al., 2004), antidiabetic (Roh et al., 2016; Yang et al., 2016), anti‐obesity (Park et al., 2018), anti‐inflammatory (Schwendimann et al., 2020), and hepatoprotective effects (Kim et al., 2019; Park et al., 2018). Recently, A. hookeri extract was shown to decrease body weight and improve lipid profiles in rats fed a high‐fat diet (Jang et al., 2018; Kim et al., 2019).…”

“…antioxidant (Cho et al, 2015;Kim et al, 2016), antimicrobial (Lucchini et al, 2018;Poznanski et al, 2004), antidiabetic (Roh et al, 2016;Yang et al, 2016), anti-obesity (Park et al, 2018), anti-inflammatory (Schwendimann et al, 2020), and hepatoprotective effects (Kim et al, 2019;Park et al, 2018). Recently, A. hookeri extract was shown to decrease body weight and improve lipid profiles in rats fed a highfat diet (Jang et al, 2018;Kim et al, 2019).…”