Effect of residues of five disinfectants in milk on acid production by strains of lactic starters used for Cheddar cheesemaking and on organoleptic properties of the cheese

Abstract

SUMMARY: The inhibitory effect of five disinfectants on acid production byStreptococcus lactisandStr. cremorisCheddar cheese starters was compared using two techniques, a laboratory scale fermentation tube test, and pilot scale cheese manufacture. Threshold inhibition concentrations (partial, total) of disinfectants (mg/1) on acid production observed in the fermentation tube were: peracetic acid/H₂O₂(0–5, > 600) iodophor (75–220, > 400), quaternary ammonium compound (QAC), (20–30, > 200), acidic anionic (60–120, 600–1200), and Na hypochlorite (400–1000, > 1000). Threshold inhibition concentrations (partial, total) observed in the cheese vat were (mg/I); peracetic acid/H₂O₂(0–5, 5–35), iodophor (15–30, 75–200), QAC (10–20, > 200), acidicanionic(30–120, > 600), and Na hypochlorite (35–400, > 400). Flavour threshold concentrations in the cheese at 4 weeks were (mg/l): peracetic acid/H₂O₂5, iodophor 8, QAC 20, acidic anionic 12, and hypochlorite 50. It is concluded that problems in cheese manufacture are unlikely to occur with hypochlorites, iodophors, and acidic anionics, but that care should be taken when using QAC and peracetic acid as sanitizers. A correlation coefficient of 0918 was computed between the two methods of determining partial acid inhibition (P< 0·005).