Continuing problems with post-pasteurization contamination of milk and cream have stimulated dairy plants to undertake intensive programs to improve sanitation practices. Sources of contamination such as air, water, containers, fillers, pumps, joints, valves, cleaners and sanitizers have received more attention by the more progressive plants. Basic steps have been found to be necessary for improved keeping quality. These are a standardized reference test such as the Moseley 5 days at 45 F test, application of trouble shooting procedures, and application of additional sanitary measures. Comparisons using the Moseley keeping quality test and CVT test showed little correlation between them. A newly designed sampler has provided means of monitoring sanitary conditions and product keeping quality. It is a 3/8-inch drilled hole with a rubber insert clamped in by a stainless steel clamp. The sampler has withstood any pressure applied to it internally under normal dairy processing and can be permanently located in any pipe line system.

Product filling equipment is still the main contributor of contamination. It was found that manual cleaning instead of CIP cleaning was a necessity in equipment that had many product sealing joints. These areas particularly vulnerable due to heavy lubricants often used. Spraying filling areas with sanitizers during processing is essential. Plant conditions change every hour during production, therefore, adjustments in procedures to avoid contamination must be exercised. Cursory examination of plants to evaluate sanitation is insufficient. The best criterion still is the bacteriological and flavor condition of the product at the consumer level.

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Author notes

1Presented at the 53rd Annual Meeting of the International Association of Milk, Food and Environmental Sanitarians, Inc., August 15–18, 1996, at Minneapolis, Minnesota.