“…AprX production reaches its maximum at 17.5 to 20 °C, which is lower than the optimal growth temperature of pseudomonads at around 30 °C (Figure ) (Buchon et al., ; Gügi et al., ). At the same time, a dramatic increase in AprX production or total enzymatic activity, due to booming AprX production, was observed in the late exponential or the early stationary phase, only if the cell density reached 10 7 to 10 8 cfu mL −1 in milk (Guinot‐Thomas, Al Ammoury, Le Roux, & Laurent, ; Matselis & Roussis, ; Pinto, Costa, Mantovani, & Vanetti, ; Stevenson, Rowe, Wisdom, & Kilpatrick, ). The close relation with high bacterial count indicates that induction of AprX may be a candidate for quorum sensing, a phenomenon by which bacteria can sense and respond to cell population size by means of chemical signals based on the N ‐acy homoserine lactones (AHLs) (Fuqua, Winans, & Greenberg, ).…”