The effect of sodium chloride, potassium nitrate and sodium nitrite on the recovery of heated bacterial spores *

Abstract

The ability of aerobic and anaerobic spores, after various degrees of heating, to produce macrocolonies in media containing different concentrations of sodium chloride, potassium nitrate and sodium nitrite has been examined. The effect of different heat treatments, roughly from Fo = 0.001 5 to Fo = 1 -5, on the inhibitory levels of these curing ingredients, showed that the more severe treatments were capable of rendering surviving spores considerably more sensitive to subsequent inhibition by concentrations of the order found in cured meats. To produce this effect, less heating was needed with two Bacillus strains than with three of Clostridium. Sodium chloride and potassium nitrate had quantitatively similar effects. The inhibitory effect of sodium nitrite increased roughly ten-fold from pH 7 to pH 6.

Protezione degli alimenti mediante sostanze chimiche e sistemi di biocontrollo

“…L'effetto dell'interazione di tutti gli ingredienti e fattori coinvolti nelle carni salate e trattate termicamente sull'attività antibotulinica è stato osservato circa quarant'anni fa e diversi studiosi hanno sottolineato che i sali impiegati per la cura delle carni semiconservate sono più efficaci nell'inibire le spore danneggiate dal calore che quelle non danneggiate 49,160 . Ricorrendo per l'inibizione solo alla salamoia e al pH, sono richieste concentrazioni più elevate della prima all'aumentare del secondo; secondo Chang e colleghi 32 nelle conserve di carne in scatola l'effetto inibitorio del sale sulle spore danneggiate termicamente potrebbe essere più importante del fattore Perigo.…”

Processing factors that influence the quality of Braunschweiger liver sausage

“…The mechanism by which nitrite inhibits Clostridia in cured meets If' was investigated by Roberts and Ingram (1966) and they concluded that as heating occurs during the processing of cured meat products, bacterial spores are rendered more sensitive to nitrite, and these heat-injured spores are less able to grow out in the presence of nitrite than are unheated spores. Duncan and Foster (1968a) confirmed the above finding and showed that commercially acceptable levels of nitrite inhibited division of cells newly emerged from germinated spores but did not interfere with germination of spores, labbe and Duncan (1970) made similar observation with C. perfringens.…”

Processing factors that influence the quality of Braunschweiger liver sausage

“…However, when the spores had been strongly heated as in canning, between 3.5% and 1.5% of salt actively inhibited the germination of spores (Gross et al,, 1946;Silliker et al, 1958;Abrohamsson et al, 1966). The spores of other bacteria are inhibited by comparatively low concentrations of salt if they have been heated (Roberts and Ingram, 1966), and it is believed that this is an important reason for the stability, under commercial conditions, of many canned products known to contain viable spores (Spencer, 1966).…”

“…The mechanism by which nitrite inhibits Clostridia in cured meets If' was investigated by Roberts and Ingram (1966) and they concluded that as heating occurs during the processing of cured meat products, bacterial spores are rendered more sensitive to nitrite, and these heat-injured spores are less able to grow out in the presence of nitrite than are unheated spores. Duncan and Foster (1968a) The Perigo factor, a powerful anticlostridal factor, was discovered by Perigo et al (1967) and Perigo and Roberts (1968) when they heated nitrite in a bacteriological culture medium.…”

“…The moderate heating applied to cured, precooked sausages does not kill bacterial spores (Tanner and Evans, 1933;Gough and AI ford, 1965;and So I berg and Elkind, 1970). In pasteurized, comminuted meat products counts of ctout 100 Bacillus and 10 Clostridium spores per gram are frequently encountered (Ingram, 1973), However, a heat treatment which does not necessarily result in complete inactivation of spores caused enough damage to prevent growth and multiplication under the conditions tested; this is generally thought to be the case in the canning of cured meats (Roberts and Ingram, 1966;Duncan and Foster, 1968a;Labbe and Duncan, 1970).…”