Food Safety in a Free Society.
A combination of factors would provide an expectation of a high degree of food safety in a free society.
Grow Your Own
For those who are competent enough agriculturally, growing your own food provides one method of ensuring a high level of food safety, as you can personally ensure that your standards are met. This method is the most basic of ensuring food safety (and availability), which can be utilized in conjunction with, or in the absence of, any of the others.
Another solution is doing business with local farmers (whose business practices you can personally inspect) for groceries. Farmers markets and the local butcher can provide a level of trust in the product, as long as you know the person to be ethical, given your knowledge of them. From this stand point, it would be valuable to get to know these people so that you can personally evaluate their business ethics.
Profit Motive and the Law of Constant Dealings
Negative experiences with a company decreases the likelihood of return business (it is cheaper to keep a customer than gain a new one from a marketing perspective, in addition to the lost revenue from lost sales) and referrals (word of mouth [experience/reputation based] advertising is the cheapest and most effective). Because of this companies would find it in their interest to provide their customers with valuable products, not selling diseased, rotted, contaminated, or otherwise undesirable food.
A person can ask trusted (trustworthy) friends and family and those whose opinions you value (IE you think they know what they are talking about through experience with them, personally) about good places to shop and eat.
Private Food Industry Associations
Private Food Industry Associations are organized to promote certain standards in food safety practices. Industry professionals set standards and enforce inspections (Either by inspectors hired directly by the association or by contracting with independent private inspectors.) to promote compliance with those standards as a condition of membership. Consumers will look for businesses affiliated with such associations as a guarantee of quality, which gives the company financial incentive to be a member of a respectable association, and therefore abide by its standards.
Standards Set by the Free Market
Consumers are able to vote for standards for food safety (whether promoted by an association or individual) with what they choose to purchase, and so food safety standards will be determined by the free market as associations seek to provide standards that will gain them the largest market share. Competition between these will also provide an expectation of a high degree of value from their service.
Consumer Reports Magazines
Professionals will review establishments and specific products, and sell those opinions to consumers as they do currently on sites such as consumerreports.org. Again, Competition between these will provide an expectation of a high level of value (within different price ranges, lifestyles, standards, etc) from their service.
Consumer Opinion Websites.
Aggregated consumer opinion sites like Yelp.com provide another avenue for evaluating and rating food merchants, where consumer experiences are cataloged and shared.
An organization such as the Better Business Bureau does a more general kind of rating that examines the basic business practices of a company, including the company’s response to customer complaints (resolved, unresolved, etc), the number of complaints received over a given period of time (as the quality of a venue can change over time, for better or worse). Membership in such an organization is dependent on maintaining an acceptable (according to the bylaws of the association) level of consumer complaints. Non-membership doesn’t mean that a business will not be evaluated by the organization.
If Something Goes Wrong
In the event that a customer is sold a poor product, they can expect to be compensated. This fact will further ensure that companies will seek to provide a high standard of service and offer to resolve disputes internally, as many companies do through return policies.
Since purchasing is essentially a transfer of title of ownership, if I buy a what I think is a disease free ham, I receive the title of ownership of that ham. However, if I, in fact, receive a diseased ham, I am still owed the ham I have the title to; a non-diseased ham. Therefore, I would have the right to the healthy ham, and if the grocer is not cooperative, I am likely to win in arbitration. (knowledge of which is likely to influence the grocers decision to cooperate.)
The offending company would also be liable for medical expenses. If I pay out of pocket for healthcare, I should be reimbursed by the company. Any dispute would be handled by a Dispute resolution organization and arbitration.
Another option is that any medical costs incurred by the diseased ham would be paid for by my health insurance provider, who could then seek compensation on my behalf.