摘要:

Nitrate and nitrite are used in meat and fish curing, and in the manufacture of certain cheeses. Nitrate itself has little antimicrobial effect and in most applications could be replaced by lower concentrations of nitrite. Further, improved hygiene diminishes the need for nitrite. The antimicrobial activity and technological needs for nitrate and nitrite are reviewed. It is concluded that the technological needs for nitrite in meat products stored at < 10°C could be met by added nitrite concentrations of 50 mg/kg. The overall effect of nitrate in salted fish appears to be marginal. In such products,Vibrio parahaemolyticusdoes not grow at salt concentrations of 10% and food poisoning by this organism is not related to the absence of nitrate or nitrite; growth ofClostridium botulinumType E (the predominant cause of botulism from fish products) is arrested by salt concentrations of 3–4%.Listeria monocytogenesin seafood cannot be controlled by nitrite. The use of nitrate in cheese production could be avoided, or at least reduced to a low level by avoiding silage with a high count of gas‐producing Clostridia and hygienic milk collection.

ISSN:0265-203X    

DOI:10.1080/02652039209374089

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This work analyses comprehensively the mechanism of action of sulphur dioxide in the process of wine‐making. The use of sulphur dioxide is still a necessity for the storage and preservation of white wines. Nevertheless, the study of its physico‐chemical and antimicrobial properties can make possible a large reduction of doses used even for white wines.

ISSN:0265-203X    

DOI:10.1080/02652039209374090

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The antimicrobial effects of sodium nitrite and sodium and potassium nitrate againstYersinia enterocoliticawere investigated in solution and in treated pork meat. Potassium nitrate and sodium nitrate showed only feeble antimicrobial activity in cultures; no antimicrobial activity was detected with sodium nitrite. Conversely, all three salts displayed apparent antimicrobial activity in pork meat, possibly due to selective effects on competitive flora.

ISSN:0265-203X    

DOI:10.1080/02652039209374091

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Generalizations about effects of irradiation may be misleading if the dose and commodities are not specified. Irradiationcouldbe used for inhibition of sprouting, disinfestation, destruction of parasites in meat, to delay maturation of fruit and for pasteurization and sterilization. In some applications it could replace chemical sprout inhibitors, fumigants and chemical preservatives; in other cases it may have unique advantages e.g. in eradication of non‐spore‐forming pathogens in dry or frozen foods. Toxicological and nutritional evaluation has repeatedly confirmed the safety of irradiated foods. Effects on nutritional quality are frequently comparable with heat treatment and sometimes more conservative, particularly if oxygen is excluded. While food irradiation could be an alternative to chemical preservatives, misinformation has led to uncertainties as to its future.

ISSN:0265-203X    

DOI:10.1080/02652039209374092

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effect of some food preservatives, such as sorbic (SA) and propionic (PA) acids, on aflatoxin production in synthetic media or in moistened (20%) wheat seeds, was investigated. The preservatives tested, added to synthetic media at sublethal concentrations both at the inoculum and after 5 days of incubation, stimulated aflatoxin production byAspergillus parasiticus.Sorbic and propionic acids are metabolized by the fungusin vivoandin vitro.Lower concentrations of PA and SA (0.05 to 0.1% w/w) in wheat seeds are ineffective against both fungal growth and aflatoxin production, whilst the combined use of butylated hydroxy toluene (BHT), and PA or SA was more effective in controlling aflatoxin production than their use as single components.

ISSN:0265-203X    

DOI:10.1080/02652039209374093

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effects of lysozyme on coagulation of milk and cheese making were studied by means of the gelograph, tristimulus colorimetry, ANS‐fluorescence (hydrophobicity) and SDS‐PAGE. Lysozyme binding to caseins caused structural differences during coagulation and it is proposed that, if the products have similar qualitative properties, lysozyme might be used as a technological aid giving shorter clotting times and higher yields.

ISSN:0265-203X    

DOI:10.1080/02652039209374094

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The organization of food surveillance in the UK is described, in particular as it has been applied to preservatives and their interaction products in foods. Applications of nitrates and nitrites as preservatives are discussed, together with the consequential exposure of consumers to these anions and their reaction products. Analytical methods for the determination of volatile and non‐volatile N‐nitroso compounds are referred to in relation to the results in food surveillance studies. Concentrations of Apparent TotalN‐nitroso Compounds (ATNC) averaged 2900 μg(N‐NO)/kg in fried smoked bacon compared with 2400 μg/kg in fried unsmoked bacon; of this, known volatile and non‐volatileN‐nitroso compounds accounted for only 10–20%. ATNC were not detected in cheeses except those manufactured with added nitrate when ATNC levels up to 210 μg(N‐NO)/kg were detected. Further studies are needed to determine the identity and toxicological properties of the non‐volatileN‐nitroso compounds.

ISSN:0265-203X    

DOI:10.1080/02652039209374095

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The stabilities of nitrate and nitrite in food systems and their reactions in such matrices are reviewed. Particular reference is made to reactions with haem proteins, smoke components and amines in foods, and the chemistry of formation ofN‐nitroso compounds from food components is discussed. Finally, the methodology available for determination of both volatile and non‐volatileN‐nitroso compounds is addressed.

ISSN:0265-203X    

DOI:10.1080/02652039209374096

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The main reason for the reactivity of sulphites in food is the nucleophilicity of the sulphite ion. The factors which determine the activity of this nucleophile are summarized and critically evaluated for concentrated systems, e.g. dehydrated foods. The distinction between free and bound sulphite is explained, and reversible binding of the additive in beverages and dehydrated foods is discussed with reference to simple theory of chemical equilibrium.

ISSN:0265-203X    

DOI:10.1080/02652039209374097

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The kinetics of the reaction of 3‐deoxyhexosulose, DH, with mercaptoethanol, ME, and glutathione, GSH, resemble those of the DH‐sulphite reaction, but the stoichiometry of the DH‐thiol reaction is 1:2 unlike that of the DH‐sulphite reaction which is 1:1. However, the rate determining step in all these reactions is the spontaneous conversion of DH to a reactive intermediate, followed by a rapid reaction of this intermediate with the nucleophile. This is also true of the reaction between DH andN‐acetylcysteine, NAC, but this thiol is less reactive than ME or GSH and less than one mole of NAC reacts with each mole of DH. Evidence for instability of NAC at pH 5.5 is presented.

ISSN:0265-203X    

DOI:10.1080/02652039209374098

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor