Spoilage temperature control

Mannitol. Whereas mannitic fermentations are seldom a problem where sulfur dioxide, pure yeasts, and temperature control are employed, Martucci (1941) has reported them in Argentina. He recommended control of the must acidity, since a high pH also favored such spoilage. A complicated polaiimetric procedure for mannitol (a sugar alcohol) in wines was presented by Salani (1937). Formation of mannite during dialysis of musts at low temperatures (8° to 10° C. (46.4° to 50° F.)) in the presence of chloroform was reported by Barbera (1933b) (possibly owing to enzyme action). 

Today, other means can be used to produce standard types of wines in these climatic conditions. Grapes are harvested at sugar concentrations compatible with complete fermentations, even in relatively hot climates. Fermentations are better controlled through sulfiting, aeration and temperature control. They are also complete. Malolac-tic fermentation can now occur without bacterial spoilage. 

Effect of Sample Dilution. To determine the effect of sample dilution on impedance measurements, shrimp samples were stored at >2(y C or for 21 d. Frozen samples were used to mimic fr h shrimp while refrigerated samples were used to represent spoilage over time. Duplicate SO-g samples were removed from storage every 7 d and used for impedance analysis. Each sample was removed from the bags, boiled for 5 min, cooled to room temperature, then transferred to a tared blender jar and diluted either 1 1 or 1 10 with sterile deionized, demineralized water. Samples were homogenized for 2 min on high. Controls consisted of water alone. 

The purpose of pasteurization, as it is practiced in the domestic industry today, is to destroy spoilage organisms, inactivate enzymes, or both. Heating to temperatures of only 150°F (65.6°C) will destroy most spoilage organisms but some heat resistant molds may require pasteurization temperatures as high as 210°F (98.9°C) for control. 

Various mildly cooked chilled product are also marketed under MAP, packaged with elevated concentrations of CO2 over the product. CO2 suppresses the growth of aerobic spoilage bacteria. Special versions of cook-chill foods are the sous-vides. Sous-vide is a process where the food is cooked under controlled conditions of temperature and time under 100°C inside heat stable, vacuumed plastic pouches [73]. 

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